多天线频谱共享CR-NOMA系统安全中断性能分析

认知无线电(CR)非正交多址接入(NOMA)网络(记为CR-NOMA)已是无线通信领域的研究热点之一。由于无线信道的开放性,使得无线网络的安全通信成为当前急需解决的问题。该文研究了频谱共享多天线CR-NOMA网络安全中断性能,首先分析了最优天线选择(OAS)方案的安全中断概率(SOP),并推导了其精确的闭合表达式。其次,分析了空时传输(STT)方案的SOP,并推导了其精确的闭合表达式。最后,对次用户两种方案的SOP渐近性能进行了分析,揭示了系统参数对SOP的影响。最后,采用Monte Carlo仿真验证了理论分析的正确性。研究发现,两种方案基站分别存在一个最优峰值发射功率,使得远距离次用户的安全中断性能最佳。仿真结果表明增大基站峰值发射功率,OAS方案的近距离次用户的SOP会始终优于STT方案,远距离次用户的SOP会劣于STT方案。

安全带来的动感

雷诺,这个世界十大汽车公司之一,法国第二大汽车公司,创立于 1898年,(?)路易·雷诺。雷诺拉古那,就是这家公司从2001

Influence of pier height on the safety of trains running on high-speed railway bridges during earthquakes

Sudden earthquakes pose a threat to the running safety of trains on high-speed railway bridges,and the stiffness of piers is one of the factors affecting the dynamic response of train-track-bridge system.In this paper,a experiment of a train running on a high-speed railway bridge is performed based on a dynamic experiment system,and the corresponding numerical model is established.The reliability of the numerical model is verified by experiments.Then,the experiment and numerical data are analyzed to reveal the pier height effects on the running safety of trains on bridges.The results show that when the pier height changes,the frequency of the bridge below the 30 m pier height changes greater;the increase of pier height causes the transverse fundamental frequency of the bridge close to that of the train,and the shaking angle and lateral displacement of the train are the largest for bridge with 50 m pier,which increases the risk of derailment;with the pier height increases from 8 m to 50 m,the derailment coefficient obtained by numerical simulations increases by 75% on average,and the spectral intensity obtained by experiments increases by 120% on average,two indicators exhibit logarithmic variation.

Some Remarks on Cocks'Identity-Based Encryption Scheme

The theory of quadratic residues plays an important role in cryptography.In 2001,Cocks developed an identity-based encryption(IBE)scheme based on quadratic residues,resolving Shamir’s 17-year-old open problem.However,a notable drawback of Cocks’scheme is the significant expansion of the ciphertext,and some of its limitations have been addressed in subsequent research.Recently,Cotan and Teşeleanu highlighted that previous studies on Cocks’scheme relied on a trial-and-error method based on Jacobi symbols to generate the necessary parameters for the encryption process.They enhanced the encryption speed of Cocks’scheme by eliminating this trialand-error method.Based on security analysis,this study concludes that the security of Cotan-Teşeleanu’s proposal cannot be directly derived from the security of the original Cocks’scheme.Furthermore,by adopting the Cotan-Teşeleanu method and introducing an additional variable as a public element,this study develops a similar enhancement scheme that not only accelerates the encryption speed but also provides security equivalent to the original Cocks’scheme.

CL-20基炸药油墨的直写成型及性能研究

以六硝基六氮杂异伍兹烷(CL-20)作为主体炸药,乙基纤维素(EC)及聚叠氮类粘结剂为粘结剂,乙酸乙酯为溶剂,配制出一种全溶性炸药油墨。采用微控直写工艺将该炸药油墨在基板上进行了书写,并对成型后所得复合物的性能进行了测试和表征。结果表明:成型样品中CL-20颗粒形貌为球形,颗粒尺寸小于1μm,均匀分布在粘结体系基体中;成型样品的密度为1.66 g/cm^3,达到理论密度的85.5%;和原料CL-20相比,复合物的撞击感度得到明显降低,特性落高比原料CL-20高出21.5cm。该配方具有良好的传爆性能,1.2mm装药宽度下,爆轰临界尺寸为0.357mm。

Study on Safe Dosage of Imazethapyr for an Imazethapyr Resistant Millet Variety and Its Effect on Weed Control

[Objective] This study aimed to investigate the safe dosage of imazethapyr for an imazethapyr resistant millet variety and its effect on weed control. [Method] The Imazethapyr resistant millet ＂M1508＂ was used as the experimental material and the experiment was arranged in a split plot design with two factors： herbicide application time and herbicide dosage. Application time was taken as the main plot with six treatments： A1 （preemergence treatment）, A2 （postemergence treatment on the 3rd d）, A3 （postemergence treatment on the 6th d）, A4 （postemergence treatment on the 9th d）, A5 （postemergence treatment on the 12th d）, A6 （postemergence treatment on the 15th d）; spraying dosage（B） with nine treatments： B1 （0 ml/hm2 , taking water as control）, B2 （750 ml/hm2 ）, B3 （1 125 ml/hm2 ）, B4 （1 500 ml/hm2 ）, B5 （2 250 ml/hm2 ）, B6 （3 000 ml/hm2 ）, B7 （4 500 ml/hm2 ）, B8 （6 000 ml/hm2）, B9 （7 500 ml/hm2 ）; water was added at 675 kg/hm2 . [Result] Imazethapyr showed a good herbicidal effect, and the imazethapyr resistant new variety M1508 also had a high drug resistance; the dosage range of 750 -7 500 ml/hm2 was safe for millet; considering the weed control efficacy, the yield and weeding cost comprehensively, postemergence treatment on the 6th day at 1 500 -2 250 ml/hm2 was the best for herbicide application. [Conclusion] Matched chemical weeding techniques to imazethapyr resistant millet varieties were preliminarily identified, and the efficacy of imazethapyr on weed control and its security on millet were investigated, providing references for the application and promotion of imazethapyr resistant millet varieties.

CAUSALITY DIAGRAM BASED SAFETY ANALYSIS OF MICRO TURBOJET ENGINE

An improved safety analysis based on the causality diagram for the complex system of micro aero-engines is presented.The study is examined by using the causality diagram in analytical failure cases due to rupture or pentration in the receiver of micro turbojet engine casing,and the comparisons are also made with the results from the traditional fault tree analysis.Experimental results show two main advantages：（1）Quantitative analysis which is more reliable for the failure analysis in jet engines can be produced by the causality diagram analysis;（2）Graphical representation of causality diagram is easier to apply in real test cases and more effective for the safety assessment.

Security of Application System

A safe and reliable application system frame based on Internet and Intranet for Stock Supervision and Administration Council of China is built up. An all sided, multi tier and multi technical security method has been adopted, which includes identity recognition, data encryption, digital signature, Domino and WWW servers, access control list, directory service, certificate authorization server, IC card and so on. The recognition system based on CA server is a high efficient, convenient and reliable system. The encryption technology and security method are proved to be reliable. The recognition system is of high security and is worthy of being popularized in some places where some special security requirements need meeting. Multi tier technology can improve the security of database. Double keys method is a useful data encryption method.

New signature scheme based on two cryptographic assumptions

In order to improve the security of the signature scheme, a digital signature based on two hard-solved problems is proposed. The discrete logarithm problem and the factoring problem are two well known hard- solved mathematical problems. Combining the E1Gamal scheme based on the discrete logarithm problem and the OSS scheme based on the factoring problem, a digital signature scheme based on these two cryptographic assumptions is proposed. The security of the proposed scheme is based on the difficulties of simultaneously solving the factoring problem and the discrete logarithm problem. So the signature scheme will be still secure under the situation that any one of the two hard-problems is solved. Compared with previous schemes, the proposed scheme is more efficient in terms of space storage, signature length and computation complexities.

SECURITY ANALYSIS BASED ON OVERSAMPLED CHAOTIC BINARY SEQUENCES

Some chaotic sequences generated from maps conjugated with tent map can be reconstructed precisely by short sequence prediction,since the problem of finite precision degrades the statistical properties of chaotic maps.This paper discusses the topological conjugation properties of the chaotic maps;analyzes in detail the reconstruction process of the chaotic sequences and the security of the oversampled chaotic map (OSCM) binary sequences.The result demonstrates that OSCM binary sequences can sustain the attack of the short sequence prediction,that is,they cant be reconstructed.Furthermore,all attack strategies aiming at the chaotic systems based on synchronization will fail,meaning that they are secure.

Percutaneous Microwave Coagulation Therapy for Patients with Primary and Metastatic Hepatic Tumors

Objective: To evaluate the efficacy and safety of percutaneous microwave coagulation therapy (PMCT) for patients with primary and metastatic hepatic tumors.Methods: The enrolled 100 patients with 186 tumor nodules who underwent PMCT included 79 cases of primary or recurrent liver cancers and 21 cases of metastatic liver cancer. The tumors were divided into two groups according to the tumor size in diameter: group A, 0.5 cm?<3 cm; group B, ≥3 cm?<5 cm. Under local and/or epidural anesthesia, a single percutaneous microwave antenna (or two antennas array applicator) was inserted directly into the tumor in the liver for thermo-coagulation with the aid of ultrasound guidance.Results: Among the 186 lesions in 100 patients with primary and metastatic liver cancers, in group A, 123 (66%) were coagulated once. A Follow-up of 6–12 months demonstrated that 112 lesions (91%) showed no local recurrence by CT or MRI; In group B, of the 63 lesions (33.87%) coagulated twice, 31 (49%) showed no local recurrence by CT or MRI during a follow-up of 6 months. There were no serious clinical side effects or complications in all the PMCT patients.Conclusion: PMCT gives satisfactory curative effect on tumors with <3 cm in size. It is partly effective on lesions ≥3 cm?<5 cm in size. It is a minimally invasive and effective therapy, can be used safely in the field of percutaneous hepatis surgery, and carried out even in patients with poor liver function. Key words hepatocellular carcinoma - microwave - coagulation - therapy

Driving Behavior Shaping Model in Road Traffic System

In order to give a new way for modeling driving behavior, identifying road traffic accident causation and solving a variety of road traffic safety problems such as driving errors prevention and driving behavior analysis, a new driving behavior shaping model is proposed, which could be used to assess the degree of effect of driving error upon road traffic safety. Driver behavior shaping model based on driving reliability and safety analysis could be used to identify the road traffic accident causation, to supply data for driver's behavior training, to evaluate driving procedures, to human factor design of road traffic system.

Safety and Tolerance of Adefovir Dipivoxil in Chinese Healthy Volunteers: A PhaseⅠRandomized and Open-Label Trial

Aim To assess the safety and tolerance of adefovir dipivoxil （ADV） in Chinese healthy volunteers. Methods A total of 52 healthy volunteers, 26 males and 26 females, aged from 19 to 26 were enrolled in the study. Forty-two subjects were randomized into 5, 10, 20, 40, and 60 mg dose groups （6 - 10 subjects in each） matched by sex and weight for single-dose trial. Ten subjects were orally given 10 mg of ADV tablets once daily for 7 d for multiple-dose trial. Physical examination, vital signs examination, electrocardiography, type-B ultrasonography, chest fluoroscopy, routine blood test, routine urine test, coagulation tests, and blood biochemical test were conducted on schedule and statistically evaluated. Results Asthenia frequently occurred in multiple-dose trial, nausea, abdominal pain, and diarrhea occurred in both single- and multiple-dose trials. ALT, bilirubin, CK, and LDH were slightly elevated. All adverse reactions and laboratory abnormalities were mild, and the frequency and severity were not related to doses. Conclusion ADV is safe and well tolerated in Chinese healthy volunteers at dose of 5 - 60 mg oncedaily or 10 nag once daily for 7 d. The recommended oral dosage regimen is 10 mg once daily. Attention should be paid to renal and liver functions, CK, AMY and LDH, if we take ADV for a long period of time.

Research on Safety of Manhuning Oral Liquid to Chicken

This study aimed to evaluate the safety of Manhuning oral liquid and to provide safety basis for clinical treatment. A total of 120 chickens of 14 days old were selected. After one week of adaptive feeding, they were evenly and randomly divided into four groups： one time the therapeutic dose （T1）, three times the therapeutic dose （T2）, five times the therapeutic dose （T3） and control （CK）. In different groups, the chickens were fed with Manhuning oral liquid according to the set doses for one week. At the beginning and at the end of the experiment, total 10 chickens were selected randomly from each group, respectively. They were weighed, and their blood was sampled for determination of routine blood indexes and examination of liver and kidney function. Organ indexes were determined, and pathological examination was conducted for the head, liver, spleen, lung and kidney of the chickens. The results showed that the body mass gain and organ indexes differed insignificantly among different groups （P〉0.05）. No significant differences were found in the routine blood indexes, serum ALT activity, albumin content, creatinine content and urea content among different groups before and after the experiment （P〉0.05）. After the administration, the head, liver, spleen, lung and kidney of the chickens showed no obvious abnormalities. In shod, Manhuning oral liquid had little impact on the physiological and biochemical indexes and had no toxic effects on the head, liver, spleen, lung and kidney of chickens, and it is a low-toxicity safe veterinary drug preparation.

Efficacy and Safety of a Continuous Wound Catheter in Open Abdominal Partial Hepatectomy

Objective To investigate the efficacy and safety of continuous local anesthetic wound infiltration following open abdominal partial hepatectomy. Methods We performed a prospective, non-randomized, concurrent and controlled study. Patients undergoing open abdominal partial hepatectomy, according to their willingness, accepted one of the following managements for the postoperative pain： continuous wound catheter （CWC） infiltration, patient-controlled epidural analgesia （PCEA）, patient-controlled intravenous analgesia of morphine （PCIAM）, and patient-controlled intravenous analgesia of sufentanil （PCIAS）. The primary outcome was postoperative visual analogue scale （VAS） scores at rest and on movement. Secondary outcomes included consumption of rescue medication, side effects, and complications associated with postoperative pain management. Results From August 2013 to December 2013, 80 patients were allocated to receive CWC （n=10）, PCEA （n=22）, PCIAM （n=29）, or PCIAS （n=19）. After adjusting for age, sex, body mass index, percentage of resected liver, operation time, and Amsterdam Preoperative Anxiety and Information Scale, there was no significant difference in the VAS scores at rest or on movement between Group CWC and the other groups, namely PCEA, PCIAM, and PCIAS, at 4, 12, 48, and 72 hours postoperatively （all P〉0.05）. The need for rescue medication was not significantly different between Group CWC and the other three groups at 48 and 72 hours postoperatively （all P〉0.05）. There was no significant difference in the incidence of postoperative nausea and vomiting or anal exsufflation time between group CWC and the other three groups （all P〉0.05）. No severe adverse effects associated with continuous wound infiltration were observed during the study period. Conclusions CWC has a comparable analgesic effect compared with traditional analgesia methods at most time points postoperatively. CWC is a safe alternative for the postoperative analgesic management of open liver surgery.

Design and Study of a High Security ATM System

Based on the characteristics of ATM system and the special requirement of financial transaction, an overall design of hardware and software structure of ATM was made. For software structure, the pattern of modules and table? drive is adopted to realize the security of financial transaction and the diagnosis of communication fault. A new method, which is based on the application layer, transport layer and network layer, is used for diagnosing communication fault. Supporting both magnetic card and IC card, the system has been put into use in real financial systems, and has brought about both economic and social effects.

Simulation of Restraint System Performance upon the Occupant's Response During Impact

Aim To study the influence of restraint system performance upon the occupant's response during impact, and provide a scientific base for occupant restraint system design. Methods \ In the light of basic theory of multibody system dynamics and impact dynamics on the basis of classical theory of impact, R W method is adopted to construct the vehicle occupant system model consisting of fourteen rigid bodies, thirty seven DOFs and slip joints for the simulation. A software named SVC3D(3 dimensional simulation of vehicle crash) is developed in the FORTRAN language. Results\ The results of simulation have a good coincidence with those of tests and the restraint system with low elongation webbing and equipped with pretensioner provides better restraint effect for the occupant. Conclusion\ The model of vehicle occupant multibody system and SVC3D are suitable for use. Occupant should be belted with low elongation webbing to a certain degree and occupant restraint system should be equipped with pretensioner.

Analyzing the safety of removal sequences for piles of an offshore jacket platform

An inevitable consequence of the development of the offshore petroleum industry is the eventual obsolescence of large offshore structures. Proper methods for removal of decommissioned offshore platforms are becoming an important topic that the oil and gas industry must pay increasing attention to. While removing sections from a decommissioned jacket platform, the stability of the remaining parts is critical The jacket danger indices D ~ and Ds defined in this paper are very useful for analyzing the safety of any procedure planned for disassembling a jacket platform. The safest piles cutting sequence can be determined easily by comparing every column of Do and Ds or simply analyzing the figures of every row ofD o and D,.

Transcatheter to Close the Patent Duetus Arteriosus and Atrial Septal Defects in Children

Objective: To evaluate the therapeutic effect, safety and complications oftranscathetering Amplatzer device in the closure of patent ductus arteriosus (PDA) and atrial septaldefects (ASD) in children. Methods: Patients with PDA (n = 25) and ASD ( n = 16), confirmed byechocardiography, were treated by transcatheterization. Amplatzer occluder device was placed by thetranscatheterization with the image support of X-ray and transthoracic echocardiography ( TTE) . TheTTE, ECG and X-ray examination were engaged to evaluate the therapeutic results on the time pointsof 24 h , 1, 3 , 6, 12 months after the operation, and all these cases were engaged to the follow-upexamination. Results: The cardioangiographic diameter was 13.0-28.0 mm ([19.3+-4.9] mm) in ASD and2.0-7.7 mm ([3.9+-1.5] mm) in PDA . The diameter of the Amplatzer occluder selected were 13.0-30.0mm ( [20.6+-5.1] mm) in ASD and 4.0-12.0 mm ([6.6+-1.9] mm) in PDA , respectively. All the Amplatzeroccluders were placed successfully. There were no complications during and after the operation.Very small residual shunt was still found soon after the operation in 10 cases , and there were noresidual or recanalization after three months of the operation. The pulmonary artery pressure andheart size were significantly decreased in follow-up examination . Conclusion: Transcatheteringclosure with Amplatzer device is an effective, simple and safe technique in the treatment of ASD andPDA in children.

Establishment of the Basic Theory of Fuze Safety Systems

Presents a series of new concepts and design ideas about the fuze safety system, establishing thereby a proposed theory and relevant mathematical descriptions. The basic the- ory indicates that any fuze safety system is a physical system comprising finite safety ele- ments each of which can independently affect the system's states, and the arming process is a dynamic one in which the extent of safety of the system changes only gradually. The theory and method can be used to analyse the arming process and to guide the development of fuze safety systems.