• Title/Summary/Keyword: Power Constraint

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Multi-channel Unconstrained Heart Rate Monitoring System for Exercising Rehabilitation Patients (재활 훈련중인 환자를 위한 다채널 무구속 심박동수 모니터링 시스템)

  • Cho, J.M.;Choi, J.H.;Park, J.H.;Nam, T.W.;Eun, J.M.
    • Journal of Biomedical Engineering Research
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    • v.29 no.3
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    • pp.191-197
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    • 2008
  • This research focused on the development of wireless telemetry system that can monitor heart rates of multiple rehabilitation patients in real time without constraint. The whole system consists of the multiple patient's side devices (PSDs) and one central monitoring system (CMS). The PSD consists of a microphone, amplifier, filter, microcontroller, and RF (Radio Frequency) modem. In addition, the PSD was designed to be wearable and low power consumption. The CMS consists of an RF modem and general PC and it was designed to monitor heart rates from multiple patients simultaneously. The system warns an alarm signal when a patient's heart rate exceeds the pre-set range for each patient. This system can be useful to monitor the heart rate of exercising rehabilitation patients and control the patients condition and the exercising level.

A Study on the Reliability Improvement of RFID System (RFID System의 신뢰성 향상에 관한 연구)

  • Ham Jung-Gi;Kwon Oh-Heung
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2006.05a
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    • pp.542-545
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    • 2006
  • In recent years, RFID is widely used in Industrial applications including factory, material flow, logistics and defense areas. In this paper, we developed a RFID baseband system with ASK modulation and convolutional channel code. A commercial ASK RF module is used and its frequency range in $350\sim351MHz$ and power is 10mW and the convolution code is constraint length k=3 and rate R=1/2. The performance is measured by frame error rate and the convolutional code is very useful in performance improvement and, also we implemented the binary search algorithm as anti-collision method and we show the wave shapes whit collision occurrence. This RFID system is designed by FPGA therefore it produces result of speed-up and improvement of reliability.

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A Danger Theory Inspired Protection Approach for Hierarchical Wireless Sensor Networks

  • Xiao, Xin;Zhang, Ruirui
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.5
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    • pp.2732-2753
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    • 2019
  • With the application of wireless sensor networks in the fields of ecological observation, defense military, architecture and urban management etc., the security problem is becoming more and more serious. Characteristics and constraint conditions of wireless sensor networks such as computing power, storage space and battery have brought huge challenges to protection research. Inspired by the danger theory in biological immune system, this paper proposes an intrusion detection model for wireless sensor networks. The model abstracts expressions of antigens and antibodies in wireless sensor networks, defines meanings and functions of danger signals and danger areas, and expounds the process of intrusion detection based on the danger theory. The model realizes the distributed deployment, and there is no need to arrange an instance at each sensor node. In addition, sensor nodes trigger danger signals according to their own environmental information, and do not need to communicate with other nodes, which saves resources. When danger is perceived, the model acquires the global knowledge through node cooperation, and can perform more accurate real-time intrusion detection. In this paper, the performance of the model is analyzed including complexity and efficiency, and experimental results show that the model has good detection performance and reduces energy consumption.

An Extended ED-H Real-Time Scheduling Algorithm for Supporting an Intelligent PMU-Based Energy Harvesting System

  • Park, Sangsoo
    • Journal of the Korea Society of Computer and Information
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    • v.27 no.12
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    • pp.17-27
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    • 2022
  • In this paper, ED-H algorithm, an optimal real-time scheduling algorithm dealing with the characteristics of the integrated energy harvester system with a capacitor, is extended to satisfy the time constraint under the blackout state which is a deliberate power-off state by an intelligent power management unit adopted in the system. If the power supply system does not have enough energy, it temporarily shuts off the power supply to protect the circuit and capacitor and resumes the supply again when the capacitor is fully charged, which may delay the task execution during these blackout states by calculating the time according to the occurrence of the events. To mitigate the problem, even if task execution is delayed by the original ED-H algorithm, the remaining time of the subsequent time units no longer can afford to delay the execution of the task is predicted in the extended algorithm and the task is forced to be scheduled to meet the time deadline. According to the simulation results, it is confirmed that the algorithm proposed in this paper has a high scheduling performance increase of 0.4% to 7.7% depending on the characteristics of the set of tasks compared to the ED-H.

Data Stream Allocation for Fair Performance in Multiuser MIMO Systems (다중 사용자 MIMO 환경에서 균등한 성능을 보장하는 데이터 스트림 할당 기법)

  • Lim, Dong-Ho;Choi, Kwon-Hue
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.12A
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    • pp.1006-1013
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    • 2009
  • This paper proposes a data stream allocation technique for fair capacity performance in multiuser multiple-input multiple-output (MIMO) systems using block diagonalization (BD) algorithm. Conventional studies have been focused on maximum sum capacity. Thus, there is a very large difference of capacity among users, since user capacity unfairly distributed according to each user channel environment. In additional, poor channel user has very small capacity, since base station allocates the power by using water-filling technique. Also, almost studies limited itself to obtain the additional gain by using the same number of data streams for all users. In this paper, we propose the technique for maximizing sum capacity under the fair performance constraint by allocating data stream according to user channel environment. Also, proposed algorithm has more gain of sum capacity and transmit power than conventional equal allocation via computer simulation.

Application of Concurrent Engineering for Conceptual design of a Future Main Battle Tank (차세대 주력전차의 개념설계를 위한 동시공학의 적용)

  • 김진우;소한균
    • Journal of the Korea Institute of Military Science and Technology
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    • v.2 no.1
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    • pp.38-60
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    • 1999
  • The main objective of this study is systemization of the technique of ROC quantification and optimization of baseline design by applying CE principle to the acquisition process of a weapon system. QFD and TOA techniques can be employed to a good working example of the conceptual design of a future main battle tank. In this paper, Product Planning Phase, the first phase of four QFD phases, is deployed in terms of eight steps including customer requirements and final product control characteristics. TOA is carried out considering only combat weight. In order to perform combat weight analysis and performance TOA, Preliminary Configuration Synthesis Methodology is used. Preliminary Configuration Synthesis Methodology employs the method of least squares and described linear equations of weight interrelation equation for each component of tank. As a result of QFD based upon the ROC, it was cleared that armor piercing power, main armament, type of ammunition, cruising range, combat weight, armor protection, power loading, threat detection and cost are primary factors influencing design and that combat weight is the most dominant one. The results of TOA based on the combat weight constraint show that 5100 lb reduction was required to satisfy the ROC. The baseline design of a future main battle tank is illustrated with assumption that all phases of QFD are employed to development and production process of subsystems, components, and parts of main battle tank. TOA is applied in iterative process between initial baseline design and ROC. The detailed design of each component is illustrated for a future main battle tank.

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An Adaptive Storage System for Enhancing Data Reliability in Solar-powered Sensor Networks (태양 에너지 기반 센서 네트워크에서 데이터의 안정성을 향상시키기 위한 적응형 저장 시스템)

  • Noh, Dong-Kun
    • Journal of KIISE:Computer Systems and Theory
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    • v.36 no.5
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    • pp.360-370
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    • 2009
  • Using solar power in wireless sensor networks requires a different approach to energy optimization from networks with battery-based nodes. Solar energy is an inexhaustible supply which can potentially allow a system to run forever, but there are several issues to be considered such as the uncertainty of energy supply and the constraint of rechargeable battery capacity. In this paper, we present SolarSS: a reliable storage system for solar-powered sensor networks, which provides a set of functions, in separate layers, such as sensory data collection, replication to prevent failure-induced data loss, and storage balancing to prevent depletion-induced data loss. SolarSS adapts the level of layers activated dynamically depending on solar energy availability, and provides an efficient resource allocation and data distribution scheme to minimize data loss.

Energy-Aware Configuration Management with Guaranteed Lifetime of Network in Multi-hop WBAN (무선 신체 망에서 망의 생존시간을 보장하는 에너지 인지 망 구성 관리 기법)

  • Seo, Su-Ho;Nah, Jae-Wook;Park, Jong-Tae
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.10B
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    • pp.981-987
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    • 2009
  • Recently, the study on wireless body area network for providing ubiquitous healthcare services has been actively done, including the standardization of the IEEE and others. Wireless body area network is usually configured in tree format using multi-hop communication mode due to the power limitation and the characteristics of human body. In this case, differently from existing sensor network, the wireless body area network tends to be disconnected due to the frequent movement of human body. The number of connections which can be supported at each node has some limitations due to the constraint imposed on power consumption. In this paper, we have proposed a heuristic algorithm for optimal selection of parent node with guaranteed QoS for a disconnected node, which considers the priority on packet transmission. Simulation has been performed to evaluate the performance of the proposed algorithm.

A New Resource Allocation Technique to Mitigate Co-Channel Interference in Cellular OFDMA Systems (OFDMA 시스템에서 셀 외곽지역의 동일 채널간섭 최소화를 위한 자원할당 기법)

  • Kim Dai-Kwan;Kim Jong-Kyung;Seo Jong-Soo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.6A
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    • pp.603-610
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    • 2006
  • This paper considers the problem of mitigating CCI(Co-channel Interference) in cellular OFDMA downlink systems. The users in the cell-edge area suffer from large CCIs, and their SINR requirements are hard to be maintained. To guarantee their QoS, we propose a new exclusive sub-carrier allocation and power control algorithm. The performance of the proposed two-step algorithm is simulated in SUI-A path-loss model, and it is compared with that of the conventional algorithm. The simulation results show that the data transmission rate in the cell-edge area was increased by 600Kbps within the same power constraint. The results indicate that with proposed algorithm, the data rate stability can be achieved independently of the user location in the cell.

Optimal Design of Magnetically Levitated Flywheel Energy Storage System Based on System Stability Using Rigid-Body Model (강체모델 기반 시스템 안정성을 고려한 자기부상 플라이휠 에너지 저장장치의 최적 설계)

  • Kim, Jung-Wan;Yoo, Seong-Yeol;Bae, Yong-Chae;Noh, Myoung-Gyu
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.3
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    • pp.283-289
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    • 2010
  • Owing to the increasing worldwide interest in green technology and renewable energy sources, flywheel energy storage systems (FESSs) are gaining importance as a viable alternative to traditional battery systems. Since the energy storage capacity of an FESS is proportional to the principal mass-moment of inertia and the square of the running speed, a design that maximizes the principal inertia while operatingrunning at the highest possible speed is important. However, the requirements for the stability of the system may impose a constraint on the optimal design. In this paper, an optimal design of an FESS that not only maximizes the energy capacity but also satisfies the requirements for system stability and reduces the sensitivity to external disturbances is proposed. Cross feedback control in combination with a conventional proportional-derivative (PD) controller is essential to reduce the effect of gyroscopic coupling and to increase the stored energy and the specific energy density.