NLoS Mitigation in ToA Localization Based on Spatial Correlation Filter and Iterative Minimum Residual

To mitigate the Non-Line-of-Sight (NLoS) error which seriously affects the localization accuracy and robustness in complex indoor environment,a novel Iterative Minimum Residual (IMR) based on the consistency hypothesis of the residual and the error is proposed in this paper.It chooses the best subset of measurements to calculate the coordinates of the unknown node by comparing the residuals obtained with different subsets of beacons.To reduce the time complexity of the IMR algorithm,Spatial Correlation Filter (SCF) is also proposed,which can remove the most serious NLoS distance with low calculation cost.Combined with the proposed SCF and IMR algorithm,nodes can be localized with high accuracy and low time complexity.Experimental results with real dataset demonstrate that the proposed algorithm can identify the NLoS range effectively with about 50% time cost of employing SCF only.

Microphone Array-Based Sound Source Localization Using Convolutional Residual Network

Microphone array-based sound source localization(SSL)is widely used in a variety of occasions such as video conferencing,robotic hearing,speech enhancement,speech recognition and so on.The traditional SSL methods cannot achieve satisfactory performance in adverse noisy and reverberant environments.In order to improve localization performance,a novel SSL algorithm using convolutional residual network(CRN)is proposed in this paper.The spatial features including time difference of arrivals(TDOAs)between microphone pairs and steered response power-phase transform(SRPPHAT)spatial spectrum are extracted in each Gammatone sub-band.The spatial features of different sub-bands with a frame are combine into a feature matrix as the input of CRN.The proposed algorithm employ CRN to fuse the spatial features.Since the CRN introduces the residual structure on the basis of the convolutional network,it reduce the difficulty of training procedure and accelerate the convergence of the model.A CRN model is learned from the training data in various reverberation and noise environments to establish the mapping regularity between the input feature and the sound azimuth.Through simulation verification,compared with the methods using traditional deep neural network,the proposed algorithm can achieve a better localization performance in SSL task,and provide better generalization capacity to untrained noise and reverberation.

NUMERICAL ANALYSIS OF RESIDUAL STRESSES IN TITANIUM ALLOY DURING ELECTRON BEAM LOCAL POST-WELD HEAT TREATMENT

The distributions of temperature and residual stresses in thin plates of BT20titanium alloy are numerically analyzed by three-dimensional finite element software duringelectron beam welding and electron beam local post-weld heat treatment (EBLPWHT). Combined withnumerical calculating results, the effects of different EBLPWHT mode and parameters, including heattreating position, heating width and heating time, on the distribution of welding residual stressesare analyzed. The results show that, the residual tensile stresses in weld center can be largelydecreased when the weld is heat treated at back preface of the plate. The numerical results alsoindicated that the magnitude of the residual longitudinal stresses of the weld and the zone vicinityof the weld is decreased, and the range of the residual longitudinal stresses is increased alongwith the increase of heating width and heating time.

LFM Radar Source Passive Localization Algorithm Based on Range Migration

Traditional single-satellite passive localization algorithms are influenced by frequency and angle measurement accuracies,resulting in error estimation of emitter position on the order of kilometers.Subsequently,a single-satellite localization algorithm based on passive synthetic aper-ture(PSA)was introduced,enabling high-precision positioning.However,its estimation of azimuth and range distance is considerably affected by the residual frequency offset(RFO)of uncoopera-tive system transceivers.Furthermore,it requires data containing a satellite flying over the radia-tion source for RFO search.After estimating the RFO,an accurate estimation of azimuth and range distance can be carried out,which is difficult to achieve in practical situations.An LFM radar source passive localization algorithm based on range migration is proposed to address the dif-ficulty in estimating frequency offset.The algorithm first provides a rough estimate of the pulse repetition time(PRT).It processes intercepted signals through range compression,range interpola-tion,and polynomial fitting to obtain range migration observations.Subsequently,it uses the changing information of range migration and an accurate PRT to formulate a system of nonlinear equations,obtaining the emitter position and a more accurate PRT through a two-step localization algorithm.Frequency offset only induces a fixed offset in range migration,which does not affect the changing information.This algorithm can also achieve high-precision localization in squint scenar-ios.Finally,the effectiveness of this algorithm is verified through simulations.

Survival prognostic analysis of laparoscopic D2 radical resection for locally advanced gastric cancer: A multicenter cohort study

BACKGROUND With the development of minimally invasive surgical techniques,the use of laparoscopic D2 radical surgery for the treatment of locally advanced gastric cancer(GC)has gradually increased.However,the effect of this procedure on survival and prognosis remains controversial.This study evaluated the survival and prognosis of patients receiving laparoscopic D2 radical resection for the treatment of locally advanced GC to provide more reliable clinical evidence,guide clinical decision-making,optimize treatment strategies,and improve the survival rate and quality of life of patients.METHODS A retrospective cohort study was performed.Clinicopathological data from 652 patients with locally advanced GC in our hospitals from December 2013 to December 2023 were collected.There were 442 males and 210 females.The mean age was 57±12 years.All patients underwent a laparoscopic D2 radical operation for distal GC.The patients were followed up in the outpatient department and by telephone to determine their tumor recurrence,metastasis,and survival.The follow-up period ended in December 2023.Normally distributed data are expressed as the mean±SD,and normally distributed data are expressed as M(Q1,Q3)or M(range).Statistical data are expressed as absolute numbers or percentages;theχ^(2) test was used for comparisons between groups,and the Mann-Whitney U nonparametric test was used for comparisons of rank data.The life table method was used to calculate the survival rate,the Kaplan-Meier method was used to construct survival curves,the log rank test was used for survival analysis,and the Cox risk regression model was used for univariate and multifactor analysis.RESULTS The median overall survival(OS)time for the 652 patients was 81 months,with a 10-year OS rate of 46.1%.Patients with TNM stages II and III had 10-year OS rates of 59.6%and 37.5%,respectively,which were significantly different(P<0.05).Univariate analysis indicated that factors such as age,maximum tumor diameter,tumor diffe-rentiation grade(low to undifferentiated),pathological TNM stage,pathological T stage,pathological N stage(N2,N3),and postoperative chemotherapy significantly influenced the 10-year OS rate for patients with locally advanced GC following laparoscopic D2 radical resection for distal stomach cancer[hazard ratio(HR):1.45,1.64,1.45,1.64,1.37,2.05,1.30,1.68,3.08,and 0.56 with confidence intervals(CIs)of 1.15-1.84,1.32-2.03,1.05-1.77,1.62-2.59,1.05-1.61,1.17-2.42,2.15-4.41,and 0.44-0.70,respectively;P<0.05].Multifactor analysis revealed that a tumor diameter greater than 4 cm,low tumor differentiation,and pathological TNM stage III were independent risk factors for the 10-year OS rate in these patients(HR:1.48,1.44,1.81 with a 95%CI:1.19-1.84).Additionally,postoperative chemotherapy emerged as an independent protective factor for the 10-year OS rate(HR:0.57,95%CI:0.45-0.73;P<0.05).CONCLUSION A maximum tumor diameter exceeding 4 cm,low tumor differentiation,and pathological TNM stage III were identified as independent risk factors for the 10-year OS rate in patients with locally advanced GC following laparoscopic D2 radical resection for distal GC.Conversely,postoperative chemotherapy was found to be an independent protective factor for the 10-year OS rate in these patients.

Secondary endoscopic submucosal dissection for locally recurrent or incompletely resected gastric neoplasms

AIM To investigate the feasibility and safety of secondary endoscopic submucosal dissection(ESD) for residual or locally recurrent gastric tumors. METHODS Between 2010 and 2017, 1623 consecutive patients underwent ESD for gastric neoplasms at a single tertiary referral center. Among these, 28 patients underwent secondary ESD for a residual or locally recurrent tumor. Our analysis compared clinicopathologic factors between primary ESD and secondary ESD groups. RESULTS The en bloc resection and curative rate of resection of secondary ESD were 92.9% and 89.3%, respectively. The average procedure time of secondary ESD was significantly longer than primary ESD(78.2 min vs 55.1 min, P = 0.004), and the adverse events rate was not significantly different but trended slightly higher in the secondary ESD group compared to the primary ESD group(10.7% vs 3.8%, P = 0.095). Patients who received secondary ESD had favorable outcomes without severe adverse events. During a mean follow-up period, no local recurrence occurred in patients who received secondary ESD. CONCLUSION Secondary ESD of residual or locally recurrent gastric tumors appears to be a feasible and curative treatment though it requires greater technical efficiency and longer procedure time.

Application of the local approach to the fatigue assessment for welded joints

The fatigue behavior of welded structures is currently determined by means of recommendations defined in terms of S-N curve corresponding to the detail classes of welded joints without taking account of the actual geometry of the weld. A new fatigue strength assessment method based on Dang Van multiaxial fatigue limit criterion was introduced, which is named the local approach and presented by Institut de Soudure recently. The local approach has advantages in taking welding residual stresses and the geometry of the weld toe and weld root into consideration. The application of the local approach to the fatigue strength assessment of low carbon steel Q235B welded joints was studied. The fatigue tests and finite element analysis results show that the local approach parameters recommended by Institut de Soudure were incorrectly for low carbon steel Q235B welded joints. With aluminum alloy welded joints being used widely, the parameters of the local approach used for aluminum alloy welded joints were obtained and verified on bases of the fatigue tests and finite element analysis.

Study on the causes of local recurrence of rectal cancer after curative resection: analysis of 213 cases

AIM To study the local recurrent rate and the causes of rectal cancer after surgery. METHODS The clinicopathological data of 213 rectal cancer patients and the follow up information were analyzed. The overall recurrent rate and the recurrent rates from different surgical appreaches were calculated. The main causes of recurrence were investigated. RESULTS Among the 213 cases, 73 (34 27%) had local recurrence. The recurrent time ranged from 3 months to 62 months after the first operation. Most of the recurrence ( 65/73 , 89 04%) occurred within 3 years after operation. CONCLUSION Local recurrence had no significant correlation with surgical methods or pathological types, but closely related to Dukes′ stages, location of primary tumors and the length of the distal rectum resected. Early resection and a wide tumor free resection margin are key factors to prevent local recurrence.

Decrease in the Ki67 index during neoadjuvant chemotherapy predicts favorable relapse-free survival in patients with locally advanced breast cancer

Objective: The purpose of this study was to explore the optimal cutoffs of the three parameters of Ki67 during NAC for predicting patient prognosis and investigate whether the optimal cutoffs of the Ki67 values were associated with relapse-free survival(RFS) or breast cancer-specific survival(BCSS).Methods: A total of 92 patients with locally advanced breast cancer(LABC), who had residual disease after NAC were retrospectively investigated.The optimal cutoff values of the Ki67 parameters were assessed by the online algorithm Cutoff Finder.Kaplan-Meier analysis, the log-rank test and Cox regression analysis were carried out to analyze survival.Results: The optimal cutoff values for the postsurgical Ki67 level and the decrease in the Ki67 level during NAC were defined as 25% and 12.5%, respectively.According to the univariate survival analysis, a higher Ki67 level in residual disease was associated with poor RFS(P = 0.004) and BCSS(P = 0.014).In addition, a Ki67 expression decrease > 12.5% during NAC was related to favorable RFS(P = 0.007), but was not related to BCSS(P = 0.452).Cox regression analysis showed that the Ki67 expression decrease(> 12.5% vs.≤ 12.5%) and histological grade(grade 3 vs.grade 1-2) were the independent factors associated with RFS(P =0.020 and P = 0.023, respectively), with HR values of 0.353(95% CI: 0.147-0.850) and 3.422(95% CI: 1.188-9.858), respectively.Conclusions: The Ki67 decrease was one of the independent factors associated with RFS in LABC patients with residual disease after receiving NAC.

Patterns of local recurrence in rectal cancer after a multidisciplinary approach

Improvements in surgery and the application of combined approaches to fight rectal cancer have succeeded in reducing the local recurrence (LR) rate and when there is LR it tends to appear later and less often in isolation. Moreover, a subtle change in the distribution of LRs with respect to the pelvis has been observed. In general terms, prior to total mesorectal excision the most common LRs were central types (perianastomotic and anterior) while lateral and posterior forms (presa-cral) have become more common since the growth in the use of combined treatments. No differences have been reported in the current pattern of LRs as a function of the type of approach used, that is, neo-adjuvant therapies (short-term or long-course radiotherapy, orchemoradiotherapy versus extended lymphadenectomy, though there is a trend towards posterior or presacral LR in patients in the Western world and lateral LR in Asia. Nevertheless, both may arise from the same mechanism. Moreover, as well as the mode of treatment, the type of LR is related to the height of the initial tumor. Nowadays most LRs are related to the advanced nature of the disease. Involvement of the circumferential radial margin and spillage of residual tumor cells from lymphatic leakage in the pelvic side wall are two plausible mechanisms for the genesis of LR. The patterns of pelvic recurrence itself (pelvic subsites) also have important implications for prognosis and are related to the potential success of salvage curative approach. The re-operability for cure and prognosis are generally better for anastomotic and anterior types than for presacral and lateral recurrences. Overall survival after LR diagnosis is lower with radio or chemoradiotherapy plus optimal surgery approaches, compared to optimal surgery alone.

Neoadjuvant vs adjuvant pelvic radiotherapy for locally advanced rectal cancer: Which is superior?

The treatment of locally advanced rectal cancer including timing and dosage of radiotherapy, degree of sphincter preservation with neoadjuvant radiotherapy, and short and long term effects of radiotherapy are controversial topics. The MEDLINE, Cochrane Library databases, and meeting proceedings from the American Society of Clinical Oncology, were searched for reports of randomized controlled trials and meta-analyses comparing neoadjuvant and adjuvant radiotherapy with surgery to surgery alone for rectal cancer. Neoadjuvant radiotherapy shows superior results in terms of local control compared to adjuvant radiotherapy. Neither adjuvant or neoadjuvant radiotherapy impacts overall survival. Short course versus long course neoadjuvant radiotherapy remains controversial. There is insufficient data to conclude that neoadjuvant therapy improves rates of sphincter preserving surgery. Radiation significantly impacts anorectal and sexual function and includes both acute and long term toxicity. Data demonstrate that neoadjuvant radiation causes less toxicity compared to adjuvant radiotherapy, and specifically short course neoadjuvant radiation results in less toxicity than long course neoadjuvant radiation. Neoadjuvant radiotherapy is the preferred modality for administering radiation in locally advanced rectal cancer. There are significant side effects from radiation, including anorectal and sexual dysfunction, which may be less with short course neoadjuvant radiation.

THREE-DIMENSIONAL CONFORMAL RADIATION THERAPY FOR LOCALLY RECURRENT NASOPHARYNGEAL CARCINOMA

Objective: To investigate the safety and effectiveness of three-dimensional conformal radiation therapy (3-D CRT) for locally recurrent nasopharyngeal carcinoma (NPC). Methods: From April 1998 to March 2000, 34 patients who had undergone previous external beam radiation therapy were retreated with 3-D CRT for locally recurrent NPC (33 poorly differentiated squamous cell carcinomas, 1 adenoma). The patients were re-staged according to Huaqing staging system with the following distribution: T1N0M0 in 5 cases, T2N0M0 in 11 cases, T3N0M0 in 12 cases, T4N0M0 in 6 cases. The maximal dimension of the gross tumor volume (GTV) ranged from 1.0 cm to 5.0 cm (median: 2.9 cm). CT simulation and 3-D planning were used to ensure full and conformal coverage of the planning target volume (PTV) by treated volume, while minimizing the absorbed dose of the adjacent normal tissue. 5–7 static conformal coplanar or noncoplanar portals were delivered for each fraction irradiation. The total dose delivered ranged from 65–70 Gy, with 2.5 Gy per fractionation, one fractionation per day, 5 days a week. Median follow-up time from 3-D CRT was 25 months (range: 12–36 months). Results: Over the follow-up period, local recurrence was observed in 3 patients, regional failure in 3, distant metastasis in 3, and six patients died; 88.2% (30/34) of the patient maintained local control, 82.4% (28/34) survived, and 76.5% (26/34) survived with no evidence of tumor. Acute complications were minor and few. The overall incidence of late complication was 20.6% (7/34), and severe complication was 14.7% (5/34), after re-irradiation with 3-D CRT. Conclusion: 3-D CRT is safety and effectiveness for most of the patients with locally recurrent NPC. Our preliminary results indicate a high local control rate and a low complication rate. The long-term curative effect and sequelae await further study.

The Theory of Vector-Valued Function in Locally Convex Space

In this paper, the vector-valued regular functions are extended to the locally convex space. The residues theory of the functions in the locally convex space is achieved. Thereby the Cauchy theory and Cauchy integral formula are extended to the locally convex space.

Unveiling the Residual Stresses,Local Micromechanical Properties and Crystallographic Texture in a Ti-6Al-4V Weld Joint

In this work,the micromechanical properties,crystallographic texture,welding residual stresses and their evolution after plastic strain were investigated in a Ti-6Al-4V alloy tungsten inert gas weld joint.It was found that the welding process affected the Young modulus and microhardness values in bothαandβphases in the different regions of the weld joint.The highest microhardness and Young modulus values of a phase were recorded in the heat-affected zone,whereas the highest values of these characteristics for theβphase were found in the fusion zone(FZ).The change in the micro mechanical properties was accompanied by a change in the crystallographic texture components of the dominant a phase from(0001)<10-10>and(11-20)<10-10>components in the base material to(10-10)<11-20>and(11-20)<3-302>components in the FZ.The introduction of tensile testing resulted in a continuous stress relaxation and improved the weld joint performances.

Improvements for matrix-type implicit temporal scheme regarding entropy fix and local time step

The matrix version of Symmetric Successive Over Relaxation(matrix-SSOR)scheme has been proved to be more efficient than the standard Lower-Upper Symmetric Gauss-Seidel(LUSGS),but less robust for high-speed flows.In order to ulteriorly improve the convergence rate as well as numerical stability of matrix-SSOR,two improvements regarding entropy fix and local time step have been proposed and validated.Firstly,an augmented entropy fix method is imposed on the inviscid Jacobian matrix and proved to be effective in two high-speed flows,in which the key parameter in entropy fix is discussed and found to be insensitive within appropriate range of values.Since the time step also has great effects on the numerical stability and convergence rate,a modified cell residual adapted local time step method with consideration of the residual history is developed,which is found to be effective for increasing the convergence rate when the matrix-SSOR is applied,but invalid when the LU-SGS is used.The proposed modified local time step method is also insensitive to the key parameter within appropriate range of values.The two modifications can be conveniently implanted into analogous matrix-type implicit schemes to improve the numerical performance.

A Residual Frequency Offset Estimation Method Based on Range Migration Fitting

Recently,researchers have proposed an emitter localization method based on passive synthetic aperture.However,the unknown residual frequency offset(RFO)between the transmit-ter and the receiver causes the received Doppler signal to shift,which affects the localization accu-racy.To solve this issue,this paper proposes a RFO estimation method based on range migration fitting.Due to the high frequency modulation slope of the linear frequency modulation(LFM)-mod-ulation radar signal,it is not affected by RFO in range compression.Therefore,the azimuth time can be estimated by fitting the peak value position of the pulse compression in range direction.Then,the matched filters are designed under different RFOs.When the zero-Doppler time obtained by the matched filters is consistent with the estimated azimuth time,the given RFO is the real RFO between the transceivers.The simulation results show that the estimation error of azimuth distance does not exceed 20 m when the received signal duration is not less than 3 s,the pulse repe-tition frequency(PRF)of the transmitter radar signal is not less than 1 kHz,the range detection is not larger than 1000 km,and the signal noise ratio(SNR)is not less than-5 dB.

3D Finite Element Numerical Simulation of Residual Stresses on Electron Beam Welded BT20 Plates

A three-dimensional finite-element model (FEM) used for calculating electron beam (EB) welding temperature and stresses fields of thin plates of BT20 titanium has been developed in which the nonlinear thermophysical and thermo-mechanical properties of the material has been considered. The welding temperature field, the distributions of residual stresses in as-welded (AW) and electron beam local post-weld heat treatment (EBLPWHT) conditions have been successfully simulated. The results show that: (1) In the weld center, the maximum magnitude of residual tensile stresses of BT20 thin plates of Ti alloy is equal to 60%- 70% of its yield strength σs. (2) The residual tensile stresses in weld center can be even decreased after EBLPWHT and the longitudinal tensile stresses are decreased about 50% compared to joints in AW conditions. (3) The numerical calculating results of residual stresses by using FEM are basically in agreement with the experimental results. Combined with numerical calculating results, the effects of electron beam welding and EBLPWHT on the distribution of welding residual stresses in thin plates of BT20 have been analyzed in detail.

Spatial autocorrelation analysis of 13 leading malignant neoplasms in Taiwan: a comparison between the 1995-1998 and 2005-2008 periods

Spatial autocorrelation methodologies, including Global Moran’s I and Local Indicators of Spatial Association statistic (LISA), were used to describe and map spatial clusters of 13 leading malignant neoplasms in Taiwan. A logistic regression fit model was also used to identify similar characteristics over time. Two time periods (1995-1998 and 2005-2008) were compared in an attempt to formulate common spatio-temporal risks. Spatial cluster patterns were identified using local spatial autocorrelation analysis. We found a significant spatio-temporal variation between the leading malignant neoplasms and well-documented spatial risk factors. For instance, in Taiwan, cancer of the oral cavity in males was found to be clustered in locations in central Taiwan, with distinct differences between the two time periods. Stomach cancer morbidity clustered in aboriginal townships, where the prevalence of Helicobacter pylori is high and even quite marked differences between the two time periods were found. A method which combines LISA statistics and logistic regression is an effective tool for the detection of space-time patterns with discontinuous data. Spatio-temporal mapping comparison helps to clarify issues such as the spatial aspects of both two time periods for leading malignant neoplasms. This helps planners to assess spatio-temporal risk factors, and to ascertain what would be the most advantageous types of health care policies for the planning and implementation of health care services. These issues can greatly affect the performance and effectiveness of health care services and also provide a clear outline for helping us to better understand the results in depth.

Explicit solutions from residual symmetry of the Boussinesq equation

The Bcklund transformation related symmetry is nonlocal, which is hard to be applied in constructing solutions for nonlinear equations. In this paper, the residual symmetry of the Boussinesq equation is localized to Lie point symmetry by introducing multiple new variables. By applying the general Lie point method, two main results are obtained： a new type of Backlund transformation is derived, from which new solutions can be generated from old ones; the similarity reduction solutions as well as corresponding reduction equations are found. The localization procedure provides an effective way to investigate interaction solutions between nonlinear waves and solitons.

AUTOMORPHISMS OF THE 2-DIMENSIONAL LINEAR GROUPS OVER LOCAL RINGS WITH 2 NOT BEING A UNIT

In this letter we shall describe the automorphisms of SL1（R） and GL1（R）, R local rings with 2 not being a unit of R and the residue field of R not being F2. In this way we obtain that the automorphisms are the standard.