基于智能床垫的心率检测系统

针对现有智能设备对睡眠过程中的心率检测效果不够理想,以及常用的检测方案有很多条件限制、无法普遍适用于大部分情况的问题,文章设计一款基于智能床垫的心率检测系统,介绍了该系统的硬件设计与信号处理过程。该系统包括数据采集、数据传输及上位机数据处理等功能,其中数据处理模块采用基于奇异值分解的算法,针对心跳信号特征进行有效成分提取和幅值修正。测试实验结果表明检测结果真实可靠。

便携式家用胎儿心率检测系统的研发与应用

从超声多普勒检测终端与智能手机两大模块分析便携式家用胎儿心率检测系统的构成,其中,超声多普勒检测终端进行超声波与反射回波的发射与接收,基于多普勒效应的支持将胎儿心率蕴藏于超声多普勒频移信号中,在终端放大与滤波频移信号之后,经音频线通过模拟信号的方式传递给智能手机,由智能手机对音频接口的麦克风模拟信号进行采集,通过胎儿心率检测算法获得胎儿实时心率值。实验表明,该便携式家用胎儿心率检测系统有较高的准确性与可靠性,功耗低且软件兼容性好,应用价值可以保证.

基于嵌入式技术的心率检测系统设计

对嵌入式技术进行了研究,报告了传统心率检测仪器便携性差、抗干扰能力不强的现状,设计了一种基于STM32 NUCLEO嵌入式芯片的心率检测系统。集STM32F411 NUCLEO开发板、心率信号预处理、数据采集、OLED激光显示、串行通讯及电源转换功能为一体,利用人体心血管活动的血管容积周期性规律,基于芯片模数转换器捕捉体表反射光变化活动时序,实现高低通滤波与人机交互。测试表明,系统抗干扰能力强,可用于家庭或社区人体医学监护。

低温深冷设备静态蒸发率自动检测系统研发探索

文中分析了国内焊接绝热气瓶静态蒸发率检测仪器存在的问题,开发能在工况条件下无需介质置换、排放,能高效、精准地进行蒸发率自动检测的系统。根据检测条件、环境和判定标准实时输出被检低温深冷设备的静态蒸发率测试值,并实现可追溯功能。

The Application of Weighted Association Rules in Host-Based Intrusion Detection System

Association rules are useful for determining correlations between items. Applying association rules to intrusion detection system (IDS) can improve the detection rate, but false positive rate is also increased. Weighted association rules are used in this paper to mine intrustion models, which can increase the detection rate and decrease the false positive rate by some extent. Based on this, the structure of host-based IDS using weighted association rules is proposed.

Privacy-preserving Distributed Location Proof Generating System

The rapid development of location-based service(LBS) drives one special kind of LBS, in which the service provider verifies user location before providing services. In distributed location proof generating schemes, preventing users from colluding with each other to create fake location proofs and protecting user's location privacy at the same time, are the main technical challenges to bring this kind of LBS into practical. Existing solutions tackle these challenges with low collusion-detecting efficiency and defected collusion-detecting method. We proposed two novel location proof generating schemes, which inversely utilized a secure secret-sharing scheme and a pseudonym scheme to settle these shortcomings. Our proposed solution resists and detects user collusion attacks in a more efficient and correct way. Meanwhile, we achieve a higher level of location privacy than that of previous work. The correctness and efficiency of our proposed solution is testified by intensive security analysis, performance analysis, as well as experiments and simulation results.

Rough Outlier Detection Based Security Risk Analysis Methodology

Security is a nonfunctional information system attribute that plays a crucial role in wide sensor network application domains. Security risk can be quantified as the combination of the probability that a sensor network system may fail and the evaluation of the severity of the damage caused by the failure. In this paper, we devise a methodology of Rough Outlier Detection (ROD) for the detection of security-based risk factor, which originates from violations of attack requirements (namely, attack risks). The methodology elaborates dimension reduction method to analyze the attack risk probability from high dimensional and nonlinear data set, and combines it with rough redundancy reduction and the distance measurement of kernel function which is obtained using the ROD. In this way, it is possible to determine the risky scenarios, and the analysis feedback can be used to improve the sensor network system design. We illustrate the methodology in the DARPA case set study using step-by-step approach and then prove that the method is effective in lowering the rate of false alarm.

Detection Performance Analysis of Spectrum Sensing in Cognitive Radio Networks with Mobile Secondary Users

The majority of existing papers about spectrum sensing have the assumption that secondary users(SUs) are stationary. However,mobility is an essential feature of mobile communications networks. In this paper,the detection performance of spectrum sensing by mobile SUs was analyzed. Three performance metrics,i.e.,detection probability,miss detection probability and false alarm probability,were thoroughly investigated. In our analysis,a critical variable was the real-time received primary user signal power by a mobile SU. Its probability distribution and mathematical expectation were analytically derived. Moreover,the three performance metrics in single-node spectrum sensing and multi-node collaborative spectrum sensing systems were also derived. Extensive simulations were performed. The results are consistent with the theoretical analysis. And it is concluded that SU mobility has a significant impact on the detection probability and the miss detection probability,but not on the false alarm probability.

Performance Analysis of Uplink Distributed Massive MIMO System with Cross-Layer Design over Rayleigh Fading Channel

The performance of uplink distributed massive multiple-input multiple-output(MIMO)systems with crosslayer design(CLD) is investigated over Rayleigh fading channel, which combines the discrete rate adaptive modulation with truncated automatic repeat request. By means of the performance analysis, the closed-form expressions of average packet error rate(APER)and overall average spectral efficiency(ASE)of distributed massive MIMO systems with CLD are derived based on the conditional probability density function of each user’s approximate effective signal-to-noise ratio(SNR)and the switching thresholds under the target packet loss rate(PLR)constraint.With these results,using the approximation of complementary error functions,the approximate APER and overall ASE are also deduced. Simulation results illustrate that the obtained theoretical ASE and APER can match the corresponding simulations well. Besides,the target PLR requirement is satisfied,and the distributed massive MIMO systems offer an obvious performance gain over the co-located massive MIMO systems.

Leak Detection in Water Distribution Systems Using Bayesian Theory and Fisher’s Law

A leak detection method based on Bayesian theory and Fisher’s law was developed for water distribution systems. A hydraulic model was associated with the parameters of leaks (location, extent). The randomness of parameter values was quantified by probability density function and updated by Bayesian theory. Values of the parameters were estimated based on Fisher’s law. The amount of leaks was estimated by back propagation neural network. Based on flow characteristics in water distribution systems, the location of leaks can be estimated. The effectiveness of the proposed method was illustrated by simulated leak data of node pressure head and flow rate of pipelines in a test pipe network, and the leaks were spotted accurately and renovated on time.

Stochastic differential equation software reliability growth model with change-point

This paper presents software reliability growth models(SRGMs) with change-point based on the stochastic differential equation(SDE).Although SRGMs based on SDE have been developed in a large scale software system,considering the variation of failure distribution in the existing models during testing time is limited.These SDE SRGMs assume that failures have the same distribution.However,in practice,the fault detection rate can be affected by some factors and may be changed at certain point as time proceeds.With respect to this issue,in this paper,SDE SRGMs with changepoint are proposed to precisely reflect the variations of the failure distribution.A real data set is used to evaluate the new models.The experimental results show that the proposed models have a fairly accurate prediction capability.

The design and calculation of the delayed neutron detection system for PWR and CEFR

This paper discussed the importance of the delayed neutron detection system.We improved the delayed neutron detection station and delayed neutron detector,so the noise was greatly decreased and the detection efficiency was greatly increased.After the improvement the stability of the detector was enhanced and the false alarm was eliminated.We introduced the principle of the gas lift pump designed for the sodium cooled fast reactor.A calculation model of the failed fuel detection system of CEFR was proposed,and from the model a code using LabWindows/CVI was developed.The minimum broken area that could be detected by the delayed neutron detection system of CEFR was calculated and the delayed neutron detection signal in a few representative transient conditions during fuel failure happened was stimulated.

Detection Probability Analysis of Space-Based AIS Signal by Using Geometrical Model

To analyze the detection probability of shipbome AIS （automatic identification system） signal from space, a mathematical model dependent upon three factors of message collision avoidance, power of signal received by satellite and interference ratio of signal received is presented in the paper. The altitude and footprint area of the AIS satellite are discussed to overcome the collision of messages transmitted in the different time slots fxom different SOTDMA （self organizing time division multiple access） cell areas, but arrive at the same time slot due to the different signal path lengths. The simulated result shows that compared to the normal LEO （low ear~ orbit） satellite system, on average the maximum signal coverage area and the maximum FOV （field of view） of the AIS satellite system are reduced by 74% and 38%. The majority of power of signal transmitted fi＇om shipborne 12W-power AIS transmitters located within the maximum signal coverage area may be received with the sufficient margin of power of signal by the LEO satellite, but the space-based AIS system generally suffers from the insufficient CIR （carrier to co-channel interference ratio） of signal received since around 95% pairs of message simultaneously received by satellites may not be correctly decoded. The insufficient CIR of signal received is the bottleneck for the high message detection probability. Therefore, the measure of separating the collision messages should be further taken by the space-based AIS system to increase the detection probability.

Utilization of Data Communication according to the IEC61850 Standard for Nuclear Power Plant Electrical Equipment Testing

This paper deals with an integration of directly measured electrical parameters with data acquired by data communication from protections and terminals into an advanced monitoring system. Based on the periodic test, the authors of this paper present the possibility of an extended evaluation and more accurate analysis of transient and failure events. For periodical testing, as implemented during the commissioning of power plants in the Czech Republic, a monitoring system of electrical equipment has been used, to record the courses of important electrical parameters and thus, proving the proper functioning of complex technological systems in various operation modes. Data from monitoring system were used to prove the successful results of the test or as a base data for further analysis of failures. The monitoring system has proved itself as a very useful device also when recording unexpected failure events, the cause of which was very quickly and accurately detected by the follow-up analysis. Initially, only the voltage and current data from measuring transformers, analogue transducers and contact relays were used as input data for the monitoring system. After the implementation of new digital protection technology and controlling terminals with inner data recorder, the data from digital devices could be also utilized for the monitoring system.

Frame Detection Based on Cyclic Autocorrelation and Constant False Alarm Rate in Burst Communication Systems

Frame detection is important in burst communication systems for its contribu- tions in frame synchronization. It locates the information bits in the received data stream at receivers. To realize frame detection in the presence of additive white Gaussian noise （AWGN） and frequency offset, a constant false alarm rate （CFAR） detector is proposed through exploitation of cyclic autocorrelation feature implied in the preamble. The frame detection can be achieved prior to bit timing recovery. The threshold setting is independent of the signal level and noise level by utilizing CFAR method. Mathematical expressions is derived in AWGN channel by considering the probability of false alarm and probability of detection, separately. Given the probability of false alarm, the mathematical relationship between the frame detection performance and EJNo of received signals is established. Ex- perimental results are also presented in accor- dance with analysis.

Gene mutations and clinical phenotypes in Chinese children with Blau syndrome

The mutations of CARD15 gene and clinical features of Chinese patients with Blau syndrome were analyzed. We identified10 missense mutations, out of which five were new: R334 L, E383 D, R471 C, C495 R and D512 F. The rest of them, R334 W,R334Q, G481 D, M513 T and R587 C, have been reported previously. Among all the mutations, R334 W, R334 Q and C495 R had the highest frequency. Blau syndrome was found at early age after birth. It began with lepidic rash and symmetric polyarthritis and was phenotypically characterized by typical rash, arthritis, iridocyclitis and arteritis. Cardiac involvement was also found in Blau syndrome. In addition to nerve deafness, renal involvement, osteochondroma and central nervous system involvement were also found in our patients. Therefore, Chinese children with Blau syndrome have unique gene mutations and complicated clinical phenotypes. Pathologic examination and CARD15 mutation testing should be considered for diagnosis as early as possible for suspected patients.

Detecting the electrical conductivity of single walled carbon nano-tubes by a DFM detection system

Rare SWCNT materials contain both metallic SWCNT （m-SWCNT） and semi-conducting SWCNT（s-SWCNT）. Since m- SWCNT and s-SWCNT have very different applications, it is necessary to differentiate them so as to further separate them for more efficient CNT utilization. To achieve this goal, the authors established a dielectric force microscope （DFM） detection system to differentiate s-SWCNT from m-SWCNT, based on different 2c~ force decided by SWCNT＇s conductivity under AC electric field. The experimental results showed that s-SWCNT can be clearly differentiated from m-SWCNT. The statistics analysis shows that the detected number proportion of s-SWCNT to m-SWCNT matches the well-known proportion 2：1 in the normally prepared CNT materials. The above results strongly verified the effectiveness of the detection system.