Using artificial neural networks for real-time observation of the endurance state of a steel specimen under loading

The surface temperature behavior of a steel specimen under bending fatigue is exactly divided into three stages: an initial temperature increase stage, a constant temperature stage and an abrupt temperature increase stage at the end of which the specimen fails. To obtain the endurance state of the specimen we use its thermal images (TIs). By applying artificial neural networks (ANNs) and other operations to these TIs we obtain spots with maximal, approximately medium and minimal temperatures. Then by using these temperatures we analytically obtain the temperatures all of spots of the specimen and localize the regions consisting of spots of relatively high temperatures. We consider such a region as one to be cracked firstly. This approach allows us to handle only those spots that are of interest and to work in real-time even by using an infrared (IR) camera and a computer with average technical features. We are using the result obtained in this study for fatigue testing the steel materials and for sensing the pre-fatigue state of a specific part of a machine being worked in order to take preventive measures before it breaks down.     

Efficient sleep spindle detection algorithm with decision tree

In this study, an efficient sleep spindle detection algorithm based on decision tree is proposed. After analyzing the EEG waveform, the decision algorithm determines the exact location of sleep spindle by evaluating the outputs of three different methods namely: Short Time Fourier Transform (STFT), Multiple Signal Classification (MUSIC) algorithm and Teager Energy Operator (TEO).The EEG records collected from patients used in this study have been recorded at the Sleep Research Center in Department of Psychiatry of Gülhane Military Medicine Academy. The obtained results are in agreement with the visual analysis of EEG evaluated by expert physicians. The method is applied to 16 distinct patients, 420,570 minutes long EEG records and the performance of the algorithm was assessed for the sleep spindles detection with 96.17% sensitivity and 95.54% specificity. As a result, it is found that the proposed sleep spindle detection algorithm is an efficient method to detect sleep spindles on EEG records.     

Simple,extensible and flexible random key predistribution schemes for wireless sensor networks using reusable key pools

Sensor nodes are tiny, low-power, computationally limited and battery constrained electromechanical devices. A sensor node contains a sensing unit and a wireless communication unit. Sensor nodes are deployed over a field for sensing an event data in the environment and transfer it towards a base station over its wireless channel. In a typical application, vast amount of sensor nodes are deployed over a field which constitute a sensor network. Sensor nodes must be customized for a specific sensor network application before the deployment. This customization is needed not only for underlying networking application, but also for security related configurations. Random key predistribution mechanisms have been proposed to provide security for wireless sensor networks. In the literature, there are well known random key predistribution schemes. Some of these schemes are secure, but quite complex to apply in real-world applications due to their node-based customization requirements, while some other are easily applicable but they do not offer reasonable security. In this paper, we propose random key predistribution schemes for wireless sensor networks that provide varying ranges of security. The proposed schemes are easily applicable in real world scenarios due to their simplicity and relaxed node customization requirements. In this respect, our schemes provide a tradeoff. Moreover, our proposed schemes show a good extensibility property. We assume prior deployment knowledge. We examine performance of our schemes and compare them with well known random key predistribution schemes.     

基于电压电流双环控制的蓄电池并网研究

针对常规蓄电池放电采用可变电阻器进行性能测试所引起的准确度低、可靠性差、操作困难等问题,文中提出了一种并网充放电的电池性能检测方式。通过对铅酸蓄电池中电荷量、温度、电流微分表达式的分析,建立由主反应支路和寄生支路组成的三阶等效数学模型。电池的充放电采用阶跃信号触发Buck-Boost双向变换电路开关通断的恒流模式。逆变电路采用电压电流双闭环控制,并经电感滤波后并入模拟电网。在MATLAB/Simulink软件上搭建的仿真模型验证结果表明蓄电池各项性能指标和并网电流动态响应良好,证明了文中所提方法的有效性和环保性。     

Hourly River Flow Forecasting: Application of Emotional Neural Network Versus Multiple Machine Learning Paradigms

Water Resources Management - Monitoring hourly river flows is indispensable for flood forecasting and disaster risk management. The objective of the present study is to develop a suite of hourly...     

水侵气藏型储气库注采相渗滞后数值模拟修正方法

以天然岩心气水多周期互驱相渗测定实验为基础,揭示了储气库多周期注采相渗滞后效应,结合Carlson和Killough经典相渗滞后理论,建立了水侵气藏型储气库多周期注采相渗滞后数值模拟修正方法,并通过建立的中低渗透砂岩水侵气藏型储气库地质模型,系统研究了多周期注采相渗滞后效应对储气库流体宏观分布规律和生产运行指标的影响....     

A Generic Model to Solve Tactical Planning Problems in Flexible Manufacturing Systems

This paper is an attempt to develop a generic modeling framework that addresses tactical planning problems of flexible manufacturing systems in a coherent manner. We propose a generic 0-1 mixed integer programming formulation, that integrates batching, loading, and routing problems with their critical aspects related to a system's performance. For this purpose, a thorough analysis is made to determine and relate system components, their attributes, and alternatives together with performance measures specific to tactical planning. This provided the justification to support our argument about generality of the model. A linear programming formulation is provided to approximate the mixed integer formulation proposed so as to overcome the problem's combinatorial complexity. The potential capability of the linear approximation proposed also is demonstrated via a small set of test problems.     

Cu(II)‐incorporated,histidine‐containing,magnetic‐metal‐complexing beads as specific sorbents for the metal chelate affinity of albumin

N‐Methacryloyl‐(L )‐histidine methyl ester (MAH) was synthesized from metharyloyl chloride and histidine. Spherical beads with an average size of 150–250 μm were obtained by the suspension polymerization of ethylene glycol dimethacrylate and MAH in an aqueous dispersion medium. Magnetic poly(ethylene glycol dimethacrylate‐co‐N‐Methacryloyl‐(L )‐histidine methyl ester) [m‐p(EGDMA‐co‐MAH)] microbeads were characterized with swelling tests, electron spin resonance, elemental analysis, and scanning electron microscopy. The specific surface area of the beads was 80.1 m²/g. m‐p(EGDMA‐co‐MAH) microbeads with a swelling ratio of 40.2% and 43.9 μmol of MAH/g were used for the adsorption of bovine serum albumin (BSA) in a batch system. The Cu(II) concentration was 4.1 μmol/g. The adsorption capacity of BSA on the Cu(II)‐incorporated beads was 19.2 mg of BSA/g. The BSA adsorption first increased with the BSA concentration and then reached a plateau, which was about 19.2 mg of BSA/g. The maximum adsorption was observed at pH 5.0, which was the isoelectric point of BSA. The BSA adsorption increased with decreasing temperature, and the maximum adsorption was achieved at 4°C. High desorption ratios (>90% of the adsorbed BSA) were achieved with 1.0M NaSCN (pH 8.0) in 30 min. The nonspecific adsorption of BSA onto the m‐p(EGDMA‐co‐MAH) beads was negligible. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2669–2677, 2004     

Itinerant Delivery of Popular Data via WIDE Hot Spots

Wireless Information Delivery Environment (WIDE) is a distributed data dissemination system, which uses IEEE 802.11b technology. WIDE aims to deliver popular information services to registered mobile clients in WLAN hot spots. Data delivery is based on broadcasting and multicasting to provide scalability and efficient use of the wireless channel. Reliability is assured with a combination of Forward Error Correction (FEC), data carousel, and ARQ techniques. This paper presents the proposed system architecture with the details of reliable and secure data dissemination mechanisms. Functional evaluation of the proposed system and mechanisms on the implemented prototype are also included in this paper. This work is partially supported by the State Planning Organization of Turkey under the grant number 98K120890, and by the Bogazici University Research Projects under the grant number 02A105D. A shorter version of this paper was presented in WONS 2004 in Madonna di Campiglio, Italy. Sinan Isik received the B.S. degree in mathematics, and the M.S. degree in computer engineering from Bogazici University, Istanbul, Turkey in 1999 and 2003, respectively. He is currently working toward for the PhD degree in computer engineering in the same university. His research interests include wireless communication, wireless ad-hoc networks and wireless sensor networks. Mehmet Yunus Donmez received his B.S. degree from Mathematics Department in 1999 and his MS degree from the Computer Engineering Department of Bogazici University, Istanbul, Turkey in 2003. He is currently studying for his PhD degree in computer engineering. His research interests are wireless networks and content delivery systems, along with QoS, multicasting and fairness issues in MANETs. Cem Ersoy received his BS and MS degrees in electrical engineering from Bogazici University, Istanbul, in 1984 and 1986, respectively. He worked as an R&D engineer in NETAS A.S. between 1984 and 1986. He received his PhD in electrical engineering from Polytechnic University, Brooklyn, New York in 1992. Currently, he is a professor and department head in the Computer Engineering Department of Bogazici University. His research interests include performance evaluation and topological design of communication networks, wireless communications and mobile applications. Dr. Ersoy is a Senior Member of IEEE.