With the development and progress of science and technology,road and bridge design has experienced rapid development,from the initial manual drawing design to the popularity of Computer-Aided Design(CAD),and then to t...With the development and progress of science and technology,road and bridge design has experienced rapid development,from the initial manual drawing design to the popularity of Computer-Aided Design(CAD),and then to today’s digital software design era.Early designers relied on hand-drawn paper design forms which was time-consuming and error-prone.Digital support for road and bridge design not only saves the design time but the design quality has also achieved a qualitative leap.This paper engages in the application of digital technology in road and bridge design,to provide technical reference for China’s road and bridge engineering design units,to promote the popularity of Civil3D and other advanced design software in the field of engineering design and development,ultimately contributing to the sustainable development of China’s road and bridge engineering.展开更多
To improve the human-physical-virtual coordination and integration of the digital twin workshop,3D visual monitoring and human-computer interaction of the digital twin workshop was studied.First,a novel 6D model of th...To improve the human-physical-virtual coordination and integration of the digital twin workshop,3D visual monitoring and human-computer interaction of the digital twin workshop was studied.First,a novel 6D model of the 3D visualization interactive system for digital twin workshops is proposed.As the traditional 5D digital twin model ignores the importance of human-computer interaction,a new dimension of the user terminal was added.A hierarchical real-time data-driven mapping model for the workshop production process is then proposed.Moreover,a real-time data acquisition method for the industrial Internet of things is proposed based on OPC UA(object linking and embedding for process control unified architecture).Based on the 6D model of the system,the process of creating a 3D visualization virtual environment based on virtual reality is introduced,in addition to a data-driven process based on the data management cloud platform.Finally,the 6D model of the system was confirmed using the blade rotor test workshop as the object,and a 3D visualization interactive system is developed.The results show that the system is more transparent,real-time,data-driven and more efficient,as well as promotes the coordination and integration of human-physical-virtual,which has practical significance for developing digital twin workshops.展开更多
We present an optical encryption method of multiple three-dimensional objects based on multiple interferences and single-pixel digital holography. By modifying the Mach-Zehnder interferometer, the interference of the ...We present an optical encryption method of multiple three-dimensional objects based on multiple interferences and single-pixel digital holography. By modifying the Mach-Zehnder interferometer, the interference of the multiple objects beams and the one reference beam is used to simultaneously encrypt multiple objects into a ciphertext. During decryption, each three-dimensional object can be decrypted independently without having to decrypt other objects. Since the single- pixel digital holography based on compressive sensing theory is introduced, the encrypted data of this method is effectively reduced. In addition, recording fewer encrypted data can greatly reduce the bandwidth of network transmission. Moreover, the compressive sensing essentially serves as a secret key that makes an intruder attack invalid, which means that the system is more secure than the conventional encryption method. Simulation results demonstrate the feasibility of the proposed method and show that the system has good security performance.展开更多
Objective:To evaluate the clinical efficacy of the preoperative digita1 design combined with three dimensional(3D)printing models to assist percutaneous kyphoplasty(PKP)treatment for thoracolumbar compression frac tur...Objective:To evaluate the clinical efficacy of the preoperative digita1 design combined with three dimensional(3D)printing models to assist percutaneous kyphoplasty(PKP)treatment for thoracolumbar compression frac tures.Methods:From January 2018 to August 2020,we obtained data of 99 patients diagnosed thoracolumbar compression fractures.These patients were divided into control group(n=50)underwent traditional PKP surgery,and observation group(n=49)underwent preoperative digital design combined with 3D printing model assisted PKP treatment.The clinical efficacy was evaluated with five parameters,including operation time,number of intraoperative radiographs,visual analogue scale(VAS)score,Cobb Angle change,and high compression rate of injured vertebrae.Results:There were statistically significant differences of operation time and number of intraoperative radio graphs between the two groups(P<0.05).For VAS score,Cobb Angle change and vertebral height compression rate,all of these three parameters were significantly improved when the patients accepted surgery teatment in two groups(P<0.05).However,there were no significant differences between control group and observation group for these three parameters either before or after surgery(P>0.05).Conclusions:Through the design of preoperative surgical guide plate and the application of 3D printing model to guide the operation,the precise design of preoperative surgical puncture site and puncture Angle of the injured vertebra was realized,the number of intraoperative radiographs was reduced,the operation time was shortened and the operation efficiency was improved.展开更多
Aim: Maxillary dental arch widths were evaluated in individuals having unilateral (UCLP) and bilateral (BCLP) cleft lip and palate (CLP) using three-dimensional (3D) digital models. Material and Method: The study had ...Aim: Maxillary dental arch widths were evaluated in individuals having unilateral (UCLP) and bilateral (BCLP) cleft lip and palate (CLP) using three-dimensional (3D) digital models. Material and Method: The study had been conducted on 80 individuals aged between 14 - 17 years having UCLP and BCLP. 40 of the individuals had UCLP, whereas 40 had BCLP. The maxillary dental models taken from patients before the treatment were scanned using Orthomodel Programme (v.1.01, Orthomodel Inc., Istanbul, Turkey) to obtain 3D imagery. Student’s t-test was used in order to assess the data obtained by using SPSS software version 22.0. Results: In BCLP, the average inter-canine distance was 17.44 ± 1.31 mm, the average inter-molar distance was 36.57 ± 1.12 mm, while inter-canine/inter-molar ratio was 0.47. Whereas in UCLP, it was 25.10 ± 0.63 mm, 42.20 ± 0.53 mm and 0.59. The inter-canine distance in UCLP was found to be large enough to be statistically significant (p 0.05), even though there were differences in inter-molar widths. Conclusion: For the stable orthodontic treatment results, one of the most important points is arch form and widths to be coherent with each other. In our study, the increase of inter-canine distance seen in UCLP indicates that in the cleft region, the maxillary arch is inclined over to the back, while the same situation in BCLP suggests that the maxillary segments are collapsed inside. The difference in the arch is highly affected by the primary surgical treatment.展开更多
Objective To discuss the measurement of bone tumor volume on the basis of three dimensional images segmentation technology. Methods Twenty patients with lacunar bone tumor from Tianjin Hospital and Tongji Hospital wer...Objective To discuss the measurement of bone tumor volume on the basis of three dimensional images segmentation technology. Methods Twenty patients with lacunar bone tumor from Tianjin Hospital and Tongji Hospital were included in the展开更多
Archaeological excavation involves disintegration, removal, and reassembly of the archaeological record;as such it is considered by many to be an unrepeatable, destructive activity. This perception has contributed to ...Archaeological excavation involves disintegration, removal, and reassembly of the archaeological record;as such it is considered by many to be an unrepeatable, destructive activity. This perception has contributed to an advancement in archaeological practice, namely, the development of computerized recording systems that digitally record archaeological excavations spatially and volumetrically during fieldwork. This paper is concerned with those archaeological sites where digital field recording has not been done. These sites, recorded by traditional methods, should not be excluded from attempts to restructure the spatial, volumetric, and stratigraphic archaeological data. A thorough methodology for the conversion of traditional records into digitized data is presented, including the detailed procedures required for three-dimensional plotting of recorded data—both the excavated material and the drawn site maps and cross-sections. Finally, the use of these methods is demonstrated on a complex Early to Middle Pleistocene site, illustrating the benefits of digitization and three-dimensional reconstruction in resolving stratigraphic and spatial questions.展开更多
Based on the experience and achievement of the"China Digital Ocean", the classification plan for Marine data elements is made, which can be classified into five, including marine point elements, marine line elements...Based on the experience and achievement of the"China Digital Ocean", the classification plan for Marine data elements is made, which can be classified into five, including marine point elements, marine line elements, marine polygon elements, marine grid elements and marine dynamic elements. In this paper, the technology of features and object-oriented method, a spatial-temporal data model is proposed, which can be applied in the large information system engineering like the "Digital Ocean", and this paper discusses the application of spatial data model, marine three-dimensional raster data model and relation data model in the building of Data Warehouse in "China Digital Ocean", and concludes the merits of these models.展开更多
The characters of marine data, such as multi-source, polymorphism, diversity and large amount, determine their differences from other data. How to store and manage marine data rationally and effectively to provide pow...The characters of marine data, such as multi-source, polymorphism, diversity and large amount, determine their differences from other data. How to store and manage marine data rationally and effectively to provide powerful data support for marine management information system and "Digital Ocean" prototype system construction is an urgent problem to solve. Different types of system planning data, such as marine resource, marine environment, marine econotny and marine management, and establishing marine data architecture frame with uniform standard are to realize the effective management of all level marine data, such as national marine data, the provincial (municipal) marine data, and meet the need of fundamental information-platform construction.展开更多
The feasibility of three-dimensional (3D) printing technology cgmbined with minimally invasive surgery in the treatment of pubic rami fractures was explored.From August 2015 to October 2017,a series of 30 patients who...The feasibility of three-dimensional (3D) printing technology cgmbined with minimally invasive surgery in the treatment of pubic rami fractures was explored.From August 2015 to October 2017,a series of 30 patients who underwent surgical stabilization of their anterior pelvic ring (all utilizing the 3D printing technology)by one surgeon at a single hospital were studied.The minimally invasive incisions were made through anterior inferior cilia spine and pubic nodule.Data collected included the operative duration,the blood loss,the damage of the important tissue,the biographic union and therecovery of the function after the operation.Measurements on inlet and outlet pelvic cardiograph were made immediately post-operation and at all follow-up clinic visits.The scores of reduction and function were measured during follow-up.Results showed that the wounds of 30 patients were healed in the first stage,and there was no injury of important structures such as blood vessels and nerves.According to the Matta criteria,excellent effectiveness was obtained in 22 cases and good in 8 cases.According to the functional evaluation criteria of Majeed,excellent effectiveness was obtained in 21 cases and good in 9 cases.It was suggested that the 3D printing technology assisted by minimally invasive surgery can better evaluate the pelvic fracture before operation,which was helpful in plate modeling, and can shorten surgery duration and reduce intraoperative blood loss and complications. The positioning accuracy was improved,and better surgical result was finally achieved.展开更多
A three-layer model for digital communication in a mine is proposed. Two basic platforms are discussed: A uniform transmission network and a uniform data warehouse. An actual,ControlNet based,transmission network plat...A three-layer model for digital communication in a mine is proposed. Two basic platforms are discussed: A uniform transmission network and a uniform data warehouse. An actual,ControlNet based,transmission network plat-form suitable for the Jining No.3 coal mine is presented. This network is an information superhighway intended to inte-grate all existing and new automation subsystems. Its standard interface can be used with future subsystems. The net-work,data structure and management decision-making all employ this uniform hardware and software. This effectively avoids the problems of system and information islands seen in traditional mine-automation systems. The construction of the network provides a stable foundation for digital communication in the Jining No.3 coal mine.展开更多
Characterizing material 3D deformation and damage is a key challenge in mechanical research. Digital volume correlation (DVC), as a tool for quantifying the internal mechanical response, can comprehensively study th...Characterizing material 3D deformation and damage is a key challenge in mechanical research. Digital volume correlation (DVC), as a tool for quantifying the internal mechanical response, can comprehensively study the extraction of key failure parameters. This review summarizes the recent progresses in the study of the internal movement of granular materials, inhomogeneous deformation of composite materials, and stress intensity factor around a crack front in static and fatigue states using DVC. To elaborate on the technique's potential, we discussed the accuracy and efficiency of the algorithm and the acquisition of real microstructure data within the material under a complex environment.展开更多
Objective: We constructed 3D-model of ONFH in computer according to three-dimensional computerized tomography (3D-CT) data. We determined the location and volume of necrosis to investigate its clinical efficacy. Metho...Objective: We constructed 3D-model of ONFH in computer according to three-dimensional computerized tomography (3D-CT) data. We determined the location and volume of necrosis to investigate its clinical efficacy. Method: Totally 92 hips (59 cases) with ONFH (44 males, 15 females) were included, with mean age of 37.5 years (range from 26 to 58). Totally 20 cases (35 hips) were induced by corticosteroid (CTSs), 31 (49 hips) induced by alcohol, 4 (4 hips) induced by trauma and 4 (4 hips) idiopathic. All the hips were categorized into stage ARCO II. Finally diagnosed by MRI, all hips were scanned by CT to acquire data in DICOM format. The images were imported into software to extract 3D-shape of femoral heads, necrotic foci, their volumes and distribution in each quadrant. Deviation of volumes between digital image and biopsy specimen was analyzed by SAS9.1 package. Correlativity between collapse and volume of necrosis under specific pathogeneses was also analyzed. Among the cases necessitating total hip arthroplasty (THA) due to advancing to ARCO III, we randomly selected 8 of them to perform 3D-CT scanning thrice prior to surgical operation. Total femoral heads harvested were torn asunder. Cubic capacity of femoral heads and necrotic foci were hereby measured and compared with those acquired from digital models. Result: Through the digital model, necrotic foci were found mainly locating within the super lateral portion of femoral head, coinciding with those observed in biopsy specimen. Average volumetric ratio of digitally acquired necrosis focus/femoral head in 58 collapsed hips was 36.8%. The ratio of the 34 hips without collapse was 17.3%. In collapsed femoral heads, the distribution of necrosis focus was 23.4% in quadrant 1 (q1), 23.6% in q2, 12.1% in q3, 14.4% in q4, 9.0% in q5, 11.8% in q6, 1.6% in q7 and 3.9% in q8. In femoral heads without collapse, the distribution was 34.2% in q1, 29.6% in q2, 11.8% in q3, 11.3% in q4, 6.0% in q5, 6.0% in q6, 0.5% in q7 and 0.4% in q8. As for the average cubic capacities of femoral heads and necrotic foci, those acquired from the digital model and biopsy specimen had no significant difference in matched-pairs test (t = -1.49, P = 0.179 for femoral heads and t = -1.52, P = 0.172 for necrotic foci). There was significant difference (F = 2.720, P = 0.035 P was respectively 0.0001 and 0.0005). Decision tree model showed that 94.6% (53/56) hips would progress into collapse if the volumetric ratio of necrotic tissue was over 23.48%. Otherwise, if distribution in q2 was over 45.13%, 83.3% (5/6) hips would progress into collapse. No collapse (0/30) would occur if the distribution of necrotic tissue in q2 was under 45.13%. Conclusion: Digital 3D-model reconstructed from CT scanning can precisely incarnate spatial orientation of necrotic foci in femoral head. Multinomial logistic regression and decision-making tree shows that volumetric ratio of necrotic tissues plays an important role in anticipating collapse of femoral head.展开更多
We compared reconstruction algorithms [filtered back projection (FBP), maximum likelihood expectation maximization (MLEM), and the simultaneous iterative reconstruction technique (SIRT)] in terms of the radiation dose...We compared reconstruction algorithms [filtered back projection (FBP), maximum likelihood expectation maximization (MLEM), and the simultaneous iterative reconstruction technique (SIRT)] in terms of the radiation dose and image quality, for exploring the possibility of decreasing the radiation dose during digital breast tomosynthesis (DBT). The three algorithms were implemented using a DBT system and experimentally evaluated using measurements, such as signal difference-to-noise ratio (SDNR) and intensity profile, on a BR3D phantom (infocus plane image). The possible radiation dose reduction, contrast improvement, and artifact reduction in DBT were evaluated using different exposure levels and the three reconstruction techniques. We performed statistical analysis (one-way analysis of variance) of the SDNR data. The effectiveness of each technique for enhancing the visibility of the BR3D phantom was quantified with regard to SDNR (FBP versus MLEM, P < 0.05;FBP vs. SIRT, P < 0.05;MLEM vs. SIRT, P = 0.945);the artifact reduction was quantified with regard to the intensity profile. MLEM and SIRT produced reconstructed images with SDNR values indicative of low-contrast visibility. The SDNR value for the half-radiation dose MLEM and SIRT images was close to that of the FBP reference radiation dose image. Artifacts were decreased in the MLEM and SIRT images (in the infocus plane) according to the intensity profiles that we obtained. With MLEM and SIRT, the radiation dose may be decreased to half comparison with FBP.展开更多
The soft robotics display huge advantages over their rigid counterparts when interacting with living organisms and fragile objects.As one of the most efficient actuators toward soft robotics,the soft pneumatic actuato...The soft robotics display huge advantages over their rigid counterparts when interacting with living organisms and fragile objects.As one of the most efficient actuators toward soft robotics,the soft pneumatic actuator(SPA)can produce large,complex responses with utilizing pressure as the only input source.In this work,a new approach that combines digital light processing(DLP)and injection-assisted post-curing is proposed to create SPAs that can realize different functionalities.To enable this,we develop a new class of photo-cross linked elastomers with tunable mechanical properties,good stretchability,and rapid curing speed.By carefully designing the geometry of the cavities embedded in the actuators,the resulting actuators can realize contracting,expanding,flapping,and twisting motions.In addition,we successfully fabricate a soft self-sensing bending actuator by injecting conductive liquids into the three-dimensional(3D)printed actuator,demonstrating that the present method has the potential to be used to manufacture intelligent soft robotic systems.展开更多
An optical encryption of three-dimensional (3D) object with digital holography was implemented. In the process of encryption, two holograms involved recording key information and 3D object were obtained. In the proces...An optical encryption of three-dimensional (3D) object with digital holography was implemented. In the process of encryption, two holograms involved recording key information and 3D object were obtained. In the process of decryption, the 3D object was reconstructed from the two holograms by extracting the object and key information, followed by multiplication of the two holograms and inverse Fresnel transform numerically. The robustness of the method was also tested for different occlusions attacks and Gaussian noises. The results showed that the method was able to encrypt and decrypt the 3D object while being robust under different occlusions attacks and Gaussian noises.展开更多
Nasal defects are facial defects caused by trauma,tumors,or congenital diseases that seriously damage a patient’s physical and mental health.Nasal defects,from skin defects to total nasal defects,require surgical rep...Nasal defects are facial defects caused by trauma,tumors,or congenital diseases that seriously damage a patient’s physical and mental health.Nasal defects,from skin defects to total nasal defects,require surgical repair and reconstruction to restore the appearance and function of the nose,which have always been challenges for rhinoplasty.The development of digital technology has increased the possibility of nasal reconstruction.Digital technology is involved in the preoperative,intraoperative,and postoperative stages of nasal construction and is of great significance in improving the effect of this surgery.This article reviews the application of major digital technologies,including three-dimensional(3D)imaging technology,computer-assisted surgical navigation,and 3D printing,in nasal reconstruction and discusses the shortcomings of the current application of digital technology.展开更多
BACKGROUND Percutaneous sclerotherapy can be used to successfully treat venous malformations(VMs)of the head,neck,and limbs.However,the standard curative effect of sclerotherapy has rarely been analyzed,and there is c...BACKGROUND Percutaneous sclerotherapy can be used to successfully treat venous malformations(VMs)of the head,neck,and limbs.However,the standard curative effect of sclerotherapy has rarely been analyzed,and there is currently no accurate statistical method to measure the volume of VMs after sclerotherapy.Here,we propose a novel threedimensional(3D)reconstruction method to evaluate this effect.OBJECTIVE To test the feasibility of 3D software(MIMICS 19.0)to evaluate the treatment effect of sclerotherapy.METHODS This retrospective study included patients with VMs on the head,neck,and limbs who were treated with ethanol sclerotherapy or foam sclerotherapy every 8 weeks.MIMICS 19.0 was used to calculate the performance of the lesion after treatment and measure the VM volumes before and after the treatment.The effect of the clinical treatment dose on the lesion was evaluated,and the treatment effect of each patient was recorded.The relationship between the number of treatments and the reduced volume of VMs was analyzed.RESULTS Based on the MIMICS-calculated regions of interest(ROI),we found that 1 mL of ethanol reduced the lesion by 473 mm3 and that one dosage of foam(1 mL of polidocanol and 4 mL air content)reduced the lesion by 2138 mm3,demonstrating that the foam sclerosing agent exhibited greater efficacy in this study.CONCLUSIONS The MIMICS 3D volume reconstruction method can effectively and safely evaluate the efficacy of sclerotherapy and provide a preoperative evaluation.This method is simple,accurate,and feasible.展开更多
Background The trochanter of the femur is a common site for bone tumors.However,locating the specificboundary of bone tumor infiltration and determining the surgical method can be challenging.The objective of thisstud...Background The trochanter of the femur is a common site for bone tumors.However,locating the specificboundary of bone tumor infiltration and determining the surgical method can be challenging.The objective of thisstudy was to review the diagnosis,treatment,and surgical outcomes of patients with tumors or tumor-like changesin the femoral trochanter after computer-assisted precise tumor resection and hip-preserving reconstruction ofthe trochanter.Methods From January 2005 to September 2020,11 patients with trochanteric tumors(aged:18–53 years;sixmales and five females)were treated in Guangzhou First People’s Hospital.The cases included aneurysmal bonecyst(n=1),giant cell tumor of bone(n=2),fibrous histiocytoma of bone(n=1),endochondroma(n=1),andfibrous dysplasia of bone(n=6).For patients with trochanteric tumors,computed tomography and magnetic resonance imaging scanning were performed before operation to obtain two-dimensional image data of the lesion.Athree-dimensional digital model of bilateral lower limbs was reconstructed by computer technology,the boundary of tumor growth was determined by computer simulation,the process of tumor resection and reconstructionwas simulated,and the personalized guide template was designed.During the operation,the personalized guideplate guided the precise resection of the tumor,and the allogeneic bone was trimmed to match the shape of thebone defect.Results All 11 patients underwent accurate resection of the tumor or tumor-like lesion and reconstruction ofthe hip.In eight cases,the lesion was confined to the trochanter,which was fixed with large segment allogeneicbone,autologous iliac bone,and proximal femoral anatomic plate.In three cases,allogeneic bone,autologousiliac bone,and femoral reconstruction nail were used to fix the tumor under the trochanter.Postoperative Xray examination showed that the repair and reconstruction of the bone defect was effective,and callus bridgingbetween the allogenic bone and autogenous bone was observed 6 months after operation.All patients recoveredtheir walking function 3–6 months after operation.The duration of the follow-up period ranged from 6 monthsto 6 years.A patient experienced recurrence of endochondroma;pathological examination revealed chondrocyticsarcoma.The remaining 10 patients were treated with segmental resection and reconstruction.The operationtime ranged 2.5–4.5 h(average:3.2 h).Intraoperative blood loss ranged from 300 to 500 ml(average:368 ml).The local recurrence rate was 9.1%,and the overall survival rate was 100%.The average Musculoskeletal TumorSociety score was 27(excellent and good for eight and three patients,respectively).Conclusions Three-dimensional computer skeleton modeling and simulation-assisted resection and reconstruction of femoral trochanteric tumor is a new surgical technique,which might markedly improve the surgical effect,shorten the surgical time,increase the overall survival rate of patients with tumors,reduce the local recurrencerate,assist in the digitization and programming of femoral trochanteric tumor surgery,and improve surgicalaccuracy.展开更多
文摘With the development and progress of science and technology,road and bridge design has experienced rapid development,from the initial manual drawing design to the popularity of Computer-Aided Design(CAD),and then to today’s digital software design era.Early designers relied on hand-drawn paper design forms which was time-consuming and error-prone.Digital support for road and bridge design not only saves the design time but the design quality has also achieved a qualitative leap.This paper engages in the application of digital technology in road and bridge design,to provide technical reference for China’s road and bridge engineering design units,to promote the popularity of Civil3D and other advanced design software in the field of engineering design and development,ultimately contributing to the sustainable development of China’s road and bridge engineering.
基金The National Natural Science Foundation of China(No.51875332)the Capacity Building Projects of Some Local Universities of Shanghai Science and Technology Commission(No.18040501600).
文摘To improve the human-physical-virtual coordination and integration of the digital twin workshop,3D visual monitoring and human-computer interaction of the digital twin workshop was studied.First,a novel 6D model of the 3D visualization interactive system for digital twin workshops is proposed.As the traditional 5D digital twin model ignores the importance of human-computer interaction,a new dimension of the user terminal was added.A hierarchical real-time data-driven mapping model for the workshop production process is then proposed.Moreover,a real-time data acquisition method for the industrial Internet of things is proposed based on OPC UA(object linking and embedding for process control unified architecture).Based on the 6D model of the system,the process of creating a 3D visualization virtual environment based on virtual reality is introduced,in addition to a data-driven process based on the data management cloud platform.Finally,the 6D model of the system was confirmed using the blade rotor test workshop as the object,and a 3D visualization interactive system is developed.The results show that the system is more transparent,real-time,data-driven and more efficient,as well as promotes the coordination and integration of human-physical-virtual,which has practical significance for developing digital twin workshops.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61405130 and 61320106015)
文摘We present an optical encryption method of multiple three-dimensional objects based on multiple interferences and single-pixel digital holography. By modifying the Mach-Zehnder interferometer, the interference of the multiple objects beams and the one reference beam is used to simultaneously encrypt multiple objects into a ciphertext. During decryption, each three-dimensional object can be decrypted independently without having to decrypt other objects. Since the single- pixel digital holography based on compressive sensing theory is introduced, the encrypted data of this method is effectively reduced. In addition, recording fewer encrypted data can greatly reduce the bandwidth of network transmission. Moreover, the compressive sensing essentially serves as a secret key that makes an intruder attack invalid, which means that the system is more secure than the conventional encryption method. Simulation results demonstrate the feasibility of the proposed method and show that the system has good security performance.
基金supported in part by the General Program of Natural Science Foundation of Hubei Province,China(Grant No.2020CFB548)a Project in 2021 of Science and Technology Support Plan of Guizhou Province,China(Grant No.202158413293820389).
文摘Objective:To evaluate the clinical efficacy of the preoperative digita1 design combined with three dimensional(3D)printing models to assist percutaneous kyphoplasty(PKP)treatment for thoracolumbar compression frac tures.Methods:From January 2018 to August 2020,we obtained data of 99 patients diagnosed thoracolumbar compression fractures.These patients were divided into control group(n=50)underwent traditional PKP surgery,and observation group(n=49)underwent preoperative digital design combined with 3D printing model assisted PKP treatment.The clinical efficacy was evaluated with five parameters,including operation time,number of intraoperative radiographs,visual analogue scale(VAS)score,Cobb Angle change,and high compression rate of injured vertebrae.Results:There were statistically significant differences of operation time and number of intraoperative radio graphs between the two groups(P<0.05).For VAS score,Cobb Angle change and vertebral height compression rate,all of these three parameters were significantly improved when the patients accepted surgery teatment in two groups(P<0.05).However,there were no significant differences between control group and observation group for these three parameters either before or after surgery(P>0.05).Conclusions:Through the design of preoperative surgical guide plate and the application of 3D printing model to guide the operation,the precise design of preoperative surgical puncture site and puncture Angle of the injured vertebra was realized,the number of intraoperative radiographs was reduced,the operation time was shortened and the operation efficiency was improved.
文摘Aim: Maxillary dental arch widths were evaluated in individuals having unilateral (UCLP) and bilateral (BCLP) cleft lip and palate (CLP) using three-dimensional (3D) digital models. Material and Method: The study had been conducted on 80 individuals aged between 14 - 17 years having UCLP and BCLP. 40 of the individuals had UCLP, whereas 40 had BCLP. The maxillary dental models taken from patients before the treatment were scanned using Orthomodel Programme (v.1.01, Orthomodel Inc., Istanbul, Turkey) to obtain 3D imagery. Student’s t-test was used in order to assess the data obtained by using SPSS software version 22.0. Results: In BCLP, the average inter-canine distance was 17.44 ± 1.31 mm, the average inter-molar distance was 36.57 ± 1.12 mm, while inter-canine/inter-molar ratio was 0.47. Whereas in UCLP, it was 25.10 ± 0.63 mm, 42.20 ± 0.53 mm and 0.59. The inter-canine distance in UCLP was found to be large enough to be statistically significant (p 0.05), even though there were differences in inter-molar widths. Conclusion: For the stable orthodontic treatment results, one of the most important points is arch form and widths to be coherent with each other. In our study, the increase of inter-canine distance seen in UCLP indicates that in the cleft region, the maxillary arch is inclined over to the back, while the same situation in BCLP suggests that the maxillary segments are collapsed inside. The difference in the arch is highly affected by the primary surgical treatment.
文摘Objective To discuss the measurement of bone tumor volume on the basis of three dimensional images segmentation technology. Methods Twenty patients with lacunar bone tumor from Tianjin Hospital and Tongji Hospital were included in the
文摘Archaeological excavation involves disintegration, removal, and reassembly of the archaeological record;as such it is considered by many to be an unrepeatable, destructive activity. This perception has contributed to an advancement in archaeological practice, namely, the development of computerized recording systems that digitally record archaeological excavations spatially and volumetrically during fieldwork. This paper is concerned with those archaeological sites where digital field recording has not been done. These sites, recorded by traditional methods, should not be excluded from attempts to restructure the spatial, volumetric, and stratigraphic archaeological data. A thorough methodology for the conversion of traditional records into digitized data is presented, including the detailed procedures required for three-dimensional plotting of recorded data—both the excavated material and the drawn site maps and cross-sections. Finally, the use of these methods is demonstrated on a complex Early to Middle Pleistocene site, illustrating the benefits of digitization and three-dimensional reconstruction in resolving stratigraphic and spatial questions.
文摘Based on the experience and achievement of the"China Digital Ocean", the classification plan for Marine data elements is made, which can be classified into five, including marine point elements, marine line elements, marine polygon elements, marine grid elements and marine dynamic elements. In this paper, the technology of features and object-oriented method, a spatial-temporal data model is proposed, which can be applied in the large information system engineering like the "Digital Ocean", and this paper discusses the application of spatial data model, marine three-dimensional raster data model and relation data model in the building of Data Warehouse in "China Digital Ocean", and concludes the merits of these models.
文摘The characters of marine data, such as multi-source, polymorphism, diversity and large amount, determine their differences from other data. How to store and manage marine data rationally and effectively to provide powerful data support for marine management information system and "Digital Ocean" prototype system construction is an urgent problem to solve. Different types of system planning data, such as marine resource, marine environment, marine econotny and marine management, and establishing marine data architecture frame with uniform standard are to realize the effective management of all level marine data, such as national marine data, the provincial (municipal) marine data, and meet the need of fundamental information-platform construction.
文摘The feasibility of three-dimensional (3D) printing technology cgmbined with minimally invasive surgery in the treatment of pubic rami fractures was explored.From August 2015 to October 2017,a series of 30 patients who underwent surgical stabilization of their anterior pelvic ring (all utilizing the 3D printing technology)by one surgeon at a single hospital were studied.The minimally invasive incisions were made through anterior inferior cilia spine and pubic nodule.Data collected included the operative duration,the blood loss,the damage of the important tissue,the biographic union and therecovery of the function after the operation.Measurements on inlet and outlet pelvic cardiograph were made immediately post-operation and at all follow-up clinic visits.The scores of reduction and function were measured during follow-up.Results showed that the wounds of 30 patients were healed in the first stage,and there was no injury of important structures such as blood vessels and nerves.According to the Matta criteria,excellent effectiveness was obtained in 22 cases and good in 8 cases.According to the functional evaluation criteria of Majeed,excellent effectiveness was obtained in 21 cases and good in 9 cases.It was suggested that the 3D printing technology assisted by minimally invasive surgery can better evaluate the pelvic fracture before operation,which was helpful in plate modeling, and can shorten surgery duration and reduce intraoperative blood loss and complications. The positioning accuracy was improved,and better surgical result was finally achieved.
基金Project 50574094 supported by the National Natural Science Foundation of China
文摘A three-layer model for digital communication in a mine is proposed. Two basic platforms are discussed: A uniform transmission network and a uniform data warehouse. An actual,ControlNet based,transmission network plat-form suitable for the Jining No.3 coal mine is presented. This network is an information superhighway intended to inte-grate all existing and new automation subsystems. Its standard interface can be used with future subsystems. The net-work,data structure and management decision-making all employ this uniform hardware and software. This effectively avoids the problems of system and information islands seen in traditional mine-automation systems. The construction of the network provides a stable foundation for digital communication in the Jining No.3 coal mine.
基金supported by the National Natural Science Foundation of China (11722221, 11272305, and 11472265)the National Key Research and Development Program of China (2017YFA0403800 and 2017YFB0702000)the Anhui Provincial Natural Science Foundation (1508085MA17)
文摘Characterizing material 3D deformation and damage is a key challenge in mechanical research. Digital volume correlation (DVC), as a tool for quantifying the internal mechanical response, can comprehensively study the extraction of key failure parameters. This review summarizes the recent progresses in the study of the internal movement of granular materials, inhomogeneous deformation of composite materials, and stress intensity factor around a crack front in static and fatigue states using DVC. To elaborate on the technique's potential, we discussed the accuracy and efficiency of the algorithm and the acquisition of real microstructure data within the material under a complex environment.
文摘Objective: We constructed 3D-model of ONFH in computer according to three-dimensional computerized tomography (3D-CT) data. We determined the location and volume of necrosis to investigate its clinical efficacy. Method: Totally 92 hips (59 cases) with ONFH (44 males, 15 females) were included, with mean age of 37.5 years (range from 26 to 58). Totally 20 cases (35 hips) were induced by corticosteroid (CTSs), 31 (49 hips) induced by alcohol, 4 (4 hips) induced by trauma and 4 (4 hips) idiopathic. All the hips were categorized into stage ARCO II. Finally diagnosed by MRI, all hips were scanned by CT to acquire data in DICOM format. The images were imported into software to extract 3D-shape of femoral heads, necrotic foci, their volumes and distribution in each quadrant. Deviation of volumes between digital image and biopsy specimen was analyzed by SAS9.1 package. Correlativity between collapse and volume of necrosis under specific pathogeneses was also analyzed. Among the cases necessitating total hip arthroplasty (THA) due to advancing to ARCO III, we randomly selected 8 of them to perform 3D-CT scanning thrice prior to surgical operation. Total femoral heads harvested were torn asunder. Cubic capacity of femoral heads and necrotic foci were hereby measured and compared with those acquired from digital models. Result: Through the digital model, necrotic foci were found mainly locating within the super lateral portion of femoral head, coinciding with those observed in biopsy specimen. Average volumetric ratio of digitally acquired necrosis focus/femoral head in 58 collapsed hips was 36.8%. The ratio of the 34 hips without collapse was 17.3%. In collapsed femoral heads, the distribution of necrosis focus was 23.4% in quadrant 1 (q1), 23.6% in q2, 12.1% in q3, 14.4% in q4, 9.0% in q5, 11.8% in q6, 1.6% in q7 and 3.9% in q8. In femoral heads without collapse, the distribution was 34.2% in q1, 29.6% in q2, 11.8% in q3, 11.3% in q4, 6.0% in q5, 6.0% in q6, 0.5% in q7 and 0.4% in q8. As for the average cubic capacities of femoral heads and necrotic foci, those acquired from the digital model and biopsy specimen had no significant difference in matched-pairs test (t = -1.49, P = 0.179 for femoral heads and t = -1.52, P = 0.172 for necrotic foci). There was significant difference (F = 2.720, P = 0.035 P was respectively 0.0001 and 0.0005). Decision tree model showed that 94.6% (53/56) hips would progress into collapse if the volumetric ratio of necrotic tissue was over 23.48%. Otherwise, if distribution in q2 was over 45.13%, 83.3% (5/6) hips would progress into collapse. No collapse (0/30) would occur if the distribution of necrotic tissue in q2 was under 45.13%. Conclusion: Digital 3D-model reconstructed from CT scanning can precisely incarnate spatial orientation of necrotic foci in femoral head. Multinomial logistic regression and decision-making tree shows that volumetric ratio of necrotic tissues plays an important role in anticipating collapse of femoral head.
文摘We compared reconstruction algorithms [filtered back projection (FBP), maximum likelihood expectation maximization (MLEM), and the simultaneous iterative reconstruction technique (SIRT)] in terms of the radiation dose and image quality, for exploring the possibility of decreasing the radiation dose during digital breast tomosynthesis (DBT). The three algorithms were implemented using a DBT system and experimentally evaluated using measurements, such as signal difference-to-noise ratio (SDNR) and intensity profile, on a BR3D phantom (infocus plane image). The possible radiation dose reduction, contrast improvement, and artifact reduction in DBT were evaluated using different exposure levels and the three reconstruction techniques. We performed statistical analysis (one-way analysis of variance) of the SDNR data. The effectiveness of each technique for enhancing the visibility of the BR3D phantom was quantified with regard to SDNR (FBP versus MLEM, P < 0.05;FBP vs. SIRT, P < 0.05;MLEM vs. SIRT, P = 0.945);the artifact reduction was quantified with regard to the intensity profile. MLEM and SIRT produced reconstructed images with SDNR values indicative of low-contrast visibility. The SDNR value for the half-radiation dose MLEM and SIRT images was close to that of the FBP reference radiation dose image. Artifacts were decreased in the MLEM and SIRT images (in the infocus plane) according to the intensity profiles that we obtained. With MLEM and SIRT, the radiation dose may be decreased to half comparison with FBP.
基金the National Natural Science Foundation of China(Nos.11572002 and 12002032)the China Postdoctoral Science Foundation(Nos.BX20200056 and 2020M670149)。
文摘The soft robotics display huge advantages over their rigid counterparts when interacting with living organisms and fragile objects.As one of the most efficient actuators toward soft robotics,the soft pneumatic actuator(SPA)can produce large,complex responses with utilizing pressure as the only input source.In this work,a new approach that combines digital light processing(DLP)and injection-assisted post-curing is proposed to create SPAs that can realize different functionalities.To enable this,we develop a new class of photo-cross linked elastomers with tunable mechanical properties,good stretchability,and rapid curing speed.By carefully designing the geometry of the cavities embedded in the actuators,the resulting actuators can realize contracting,expanding,flapping,and twisting motions.In addition,we successfully fabricate a soft self-sensing bending actuator by injecting conductive liquids into the three-dimensional(3D)printed actuator,demonstrating that the present method has the potential to be used to manufacture intelligent soft robotic systems.
文摘An optical encryption of three-dimensional (3D) object with digital holography was implemented. In the process of encryption, two holograms involved recording key information and 3D object were obtained. In the process of decryption, the 3D object was reconstructed from the two holograms by extracting the object and key information, followed by multiplication of the two holograms and inverse Fresnel transform numerically. The robustness of the method was also tested for different occlusions attacks and Gaussian noises. The results showed that the method was able to encrypt and decrypt the 3D object while being robust under different occlusions attacks and Gaussian noises.
基金supported by the Clinical Key Project of the Peking University Third Hospital(grant no.BYSYFY2021005).
文摘Nasal defects are facial defects caused by trauma,tumors,or congenital diseases that seriously damage a patient’s physical and mental health.Nasal defects,from skin defects to total nasal defects,require surgical repair and reconstruction to restore the appearance and function of the nose,which have always been challenges for rhinoplasty.The development of digital technology has increased the possibility of nasal reconstruction.Digital technology is involved in the preoperative,intraoperative,and postoperative stages of nasal construction and is of great significance in improving the effect of this surgery.This article reviews the application of major digital technologies,including three-dimensional(3D)imaging technology,computer-assisted surgical navigation,and 3D printing,in nasal reconstruction and discusses the shortcomings of the current application of digital technology.
文摘BACKGROUND Percutaneous sclerotherapy can be used to successfully treat venous malformations(VMs)of the head,neck,and limbs.However,the standard curative effect of sclerotherapy has rarely been analyzed,and there is currently no accurate statistical method to measure the volume of VMs after sclerotherapy.Here,we propose a novel threedimensional(3D)reconstruction method to evaluate this effect.OBJECTIVE To test the feasibility of 3D software(MIMICS 19.0)to evaluate the treatment effect of sclerotherapy.METHODS This retrospective study included patients with VMs on the head,neck,and limbs who were treated with ethanol sclerotherapy or foam sclerotherapy every 8 weeks.MIMICS 19.0 was used to calculate the performance of the lesion after treatment and measure the VM volumes before and after the treatment.The effect of the clinical treatment dose on the lesion was evaluated,and the treatment effect of each patient was recorded.The relationship between the number of treatments and the reduced volume of VMs was analyzed.RESULTS Based on the MIMICS-calculated regions of interest(ROI),we found that 1 mL of ethanol reduced the lesion by 473 mm3 and that one dosage of foam(1 mL of polidocanol and 4 mL air content)reduced the lesion by 2138 mm3,demonstrating that the foam sclerosing agent exhibited greater efficacy in this study.CONCLUSIONS The MIMICS 3D volume reconstruction method can effectively and safely evaluate the efficacy of sclerotherapy and provide a preoperative evaluation.This method is simple,accurate,and feasible.
文摘Background The trochanter of the femur is a common site for bone tumors.However,locating the specificboundary of bone tumor infiltration and determining the surgical method can be challenging.The objective of thisstudy was to review the diagnosis,treatment,and surgical outcomes of patients with tumors or tumor-like changesin the femoral trochanter after computer-assisted precise tumor resection and hip-preserving reconstruction ofthe trochanter.Methods From January 2005 to September 2020,11 patients with trochanteric tumors(aged:18–53 years;sixmales and five females)were treated in Guangzhou First People’s Hospital.The cases included aneurysmal bonecyst(n=1),giant cell tumor of bone(n=2),fibrous histiocytoma of bone(n=1),endochondroma(n=1),andfibrous dysplasia of bone(n=6).For patients with trochanteric tumors,computed tomography and magnetic resonance imaging scanning were performed before operation to obtain two-dimensional image data of the lesion.Athree-dimensional digital model of bilateral lower limbs was reconstructed by computer technology,the boundary of tumor growth was determined by computer simulation,the process of tumor resection and reconstructionwas simulated,and the personalized guide template was designed.During the operation,the personalized guideplate guided the precise resection of the tumor,and the allogeneic bone was trimmed to match the shape of thebone defect.Results All 11 patients underwent accurate resection of the tumor or tumor-like lesion and reconstruction ofthe hip.In eight cases,the lesion was confined to the trochanter,which was fixed with large segment allogeneicbone,autologous iliac bone,and proximal femoral anatomic plate.In three cases,allogeneic bone,autologousiliac bone,and femoral reconstruction nail were used to fix the tumor under the trochanter.Postoperative Xray examination showed that the repair and reconstruction of the bone defect was effective,and callus bridgingbetween the allogenic bone and autogenous bone was observed 6 months after operation.All patients recoveredtheir walking function 3–6 months after operation.The duration of the follow-up period ranged from 6 monthsto 6 years.A patient experienced recurrence of endochondroma;pathological examination revealed chondrocyticsarcoma.The remaining 10 patients were treated with segmental resection and reconstruction.The operationtime ranged 2.5–4.5 h(average:3.2 h).Intraoperative blood loss ranged from 300 to 500 ml(average:368 ml).The local recurrence rate was 9.1%,and the overall survival rate was 100%.The average Musculoskeletal TumorSociety score was 27(excellent and good for eight and three patients,respectively).Conclusions Three-dimensional computer skeleton modeling and simulation-assisted resection and reconstruction of femoral trochanteric tumor is a new surgical technique,which might markedly improve the surgical effect,shorten the surgical time,increase the overall survival rate of patients with tumors,reduce the local recurrencerate,assist in the digitization and programming of femoral trochanteric tumor surgery,and improve surgicalaccuracy.