• 제목/요약/키워드: Link quality

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CREEC: Chain Routing with Even Energy Consumption

  • Shin, Ji-Soo;Suh, Chang-Jin
    • Journal of Communications and Networks
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    • 제13권1호
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    • pp.17-25
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    • 2011
  • A convergecast is a popular routing scheme in wireless sensor networks (WSNs) in which every sensor node periodically forwards measured data along configured routing paths to a base station (BS). Prolonging lifetimes in energy-limited WSNs is an important issue because the lifetime of a WSN influences on its quality and price. Low-energy adaptive clustering hierarchy (LEACH) was the first attempt at solving this lifetime problem in convergecast WSNs, and it was followed by other solutions including power efficient gathering in sensor information systems (PEGASIS) and power efficient data gathering and aggregation protocol (PEDAP). Our solution-chain routing with even energy consumption (CREEC)-solves this problem by achieving longer average lifetimes using two strategies: i) Maximizing the fairness of energy distribution at every sensor node and ii) running a feedback mechanism that utilizes a preliminary simulation of energy consumption to save energy for depleted Sensor nodes. Simulation results confirm that CREEC outperforms all previous solutions such as LEACH, PEGASIS, PEDAP, and PEDAP-power aware (PA) with respect to the first node death and the average lifetime. CREEC performs very well at all WSN sizes, BS distances and battery capacities with an increased convergecast delay.

The central regulator p62 between ubiquitin proteasome system and autophagy and its role in the mitophagy and Parkinson's disease

  • Shin, Woo Hyun;Park, Joon Hyung;Chung, Kwang Chul
    • BMB Reports
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    • 제53권1호
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    • pp.56-63
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    • 2020
  • The ubiquitin-proteasome system (UPS) and autophagy are two major degradative pathways of proteins in eukaryotic cells. As about 30% of newly synthesized proteins are known to be misfolded under normal cell conditions, the precise and timely operation of the UPS and autophagy to remove them as well as their tightly controlled regulation, is so important for proper cell function and survival. In the UPS, target proteins are labeled by small proteins called ubiquitin, which are then transported to the proteasome complex for degradation. Alternatively, many greatly damaged proteins are believed to be delivered to the lysosome for autophagic degradation. Although these autophagy and UPS pathways have not been considered to be directly related, many recent studies proposed their close link and dynamic interconversion. In this review, we'll focus on the several regulatory molecules that function in both UPS and autophagy and their crosstalk. Among the proposed multiple modulators, we will take a closer look at the so-called main connector of UPS-autophagy regulation, p62. Last, the functional role of p62 in the mitophagy and its implication for the pathogenesis of Parkinson's disease, one of the major neurodegenerative diseases, will be briefly reviewed.

The Water Resource Management Framework in New Zealand: A Case Study of Moving towards a Less Adversarial Approach

  • Davie, Tim
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2010년도 학술발표회
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    • pp.82-90
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    • 2010
  • New Zealand appears to be a water rich country; however there are considerable water allocation issues. Mostly these revolve around balancing environmental concerns with economic development. The largest economic sector is agriculture which currently utilizes around 80% of the allocated water and has considerable potential to increase in size. The resource management framework that New Zealand has developed over the past twenty years revolves around local decision-making and sustainable management principles. As the demands for water have grown there has been growing concern that this framework is inadequate to deal with the issues of declining water quantity and quality through agricultural intensification. In Canterbury, the region with the highest water allocation and demand, a new approach is being trialed. The Canterbury Water Management Strategy (CWMS) recognizes the need for: ecological restoration for past damage; infrastructure development for increased irrigation; and the need to link infrastructure with more efficient use of water by both existing and new water users. These three elements are recognized as having equal value. The CWMS builds on the local decision-making concept but is deliberately aimed at consensus building in order to remove expensive and adversarial resource management hearings. It is practical enough to recognize that economic development is needed but that it need not proceed in conflict with the environment, but rather can be a means towards environmental improvement.

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IEEE 802.11에서 멀티미디어 QoS 보장을 위한 무선 측정 기반 TFRC 기법 (Wireless Measurement based TFRC for QoS Provisioning over IEEE 802.11)

  • 변재영
    • 한국통신학회논문지
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    • 제30권4B호
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    • pp.202-209
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    • 2005
  • 본 논문에서는 first-hop 무선 채널을 갖는 무-유선망에서 채널 특성에 따라 코딩 비트율을 조절할 수 있는 동적 TCP-friendly 비트율 제어방식 (TFRC)을 제안한다. 제안되는 비트율 제어 기법은 무선망을 통해 전송되는 멀티미디어 플로우의 QoS 성능 저하 현상을 피하기 위해 패킷 손실 통계자료를 이용한 새로운 무선 손실 구별 알고리즘을 사용하고 있다. 이 알고리즘은 무-유선망에서 TCP 플로우와 함께 백본 대역폭을 공유하는 동안 TCP-friendly하도록 비트율을 생성한다. 실험 결과를 통해 제안하는 비트율 제어방식의 시스템은 TFRC 흐름 제어에서 무선 손실의 영향을 제거하고 신뢰성이 낮은 무선 링크에 의해서 발생되는 비디오 스트림의 갑작스런 품질 저하 현상을 상당히 줄일 수 있음을 알 수 있다.

A full-color anaglyph three-dimensional display system using active color filter glasses

  • Kim, Jong-Hyun;Kim, Young-Hoon;Hong, Ji-Soo;Park, Gil-Bae;Hong, Kee-Hoon;Min, Sung-Wook;Lee, Byoung-Ho
    • Journal of Information Display
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    • 제12권1호
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    • pp.37-41
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    • 2011
  • Presented herein is a novel stereoscopic three-dimensional (3D) display system with active color filter glasses. This system provides full-color 3D images by applying the time-multiplexing technique on the original anaglyph method. By switching between the opposite anaglyph statuses, a full-color anaglyph is presented. A liquid crystal panel from a 3D monitor serves as an active color filter operating at 120 Hz. A display panel and a color filter are connected to one graphic card as a dual-link system, for synchronization. To test the quality of this system, a left/right-eye image separation test and an experiment with stereoscopic images were carried out. Although there was some crosstalk and blur, the system, as expected, provided full-color 3D display. This system overcomes a monochromatic 3D image, which is the major weakness of the original anaglyph system.

전술환경에서의 VoIP 서비스를 위한 Dynamic QoS 기법 연구 (Dynamic QoS Mechanism for supporting VoIP Service in Tactical Communication Environment)

  • 신동윤;김영길
    • 한국정보통신학회:학술대회논문집
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    • 한국해양정보통신학회 2011년도 추계학술대회
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    • pp.367-370
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    • 2011
  • 군 전술통신환경은 ALL-IP 기반에서 음성, 영상, 문자 등의 다양한 서비스 제공을 목적으로 진화되고 있다. 제약조건이 많은 전술통신 인프라 환경에서 가입자의 요구 수준에 맞는 서비스의 품질 수준을 보장하면서 이러한 서비스를 제공하기 위해서는 전술통신환경의 무선 전송링크, 부대단위 및 개인 이동성 등의 특성을 고려한 서비스 품질 보장 방안이 요구된다. 이 논문은 전술통신환경에서 개인별 또는 임무별로 차별화 된 서비스 품질 보장을 위하여 QoS 제공 수준을 서비스 시점에 VoIP 교환기가 동적으로 결정함으로써 사용자의 이동상황에 관계없이 원래 받고 있던 동일한 서비스 품질을 제공받을 수 있는 기법을 제시한다.

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농촌지역 노인의 짠맛 기호도와 식습관 및 건강 위험인자와의 관계 (The Relationship between Dietary Behaviors/health Risk Factors and Preference for Salty Taste among Korean Elderly People Living in Rural Areas)

  • 이미숙
    • 대한지역사회영양학회지
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    • 제19권5호
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    • pp.448-458
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    • 2014
  • Objectives: Increasing salt preferences with age are said to increase preferences of salty foods, thereby leading to greater sodium consumption, which has further implication for hypertension. This study examined the link between preference of salty taste and dietary factors and health-related risk factors in Korean elderly people. Methods: We studied 312 elderly individuals aged > 65 years (male, 100 and female, 212). With each subject, pleasant concentration of NaCl was estimated using the sip-and-spit method. Dietary habits, food preferences, consumption frequencies, anthropometric and biochemical assessment were assessed. Results: The pleasant salt concentration was significantly increased in individuals older than 75 years (p < 0.05). Subjects who liked high concentration of salt showed significantly higher preferences for salty foods (p < 0.001). Results showed significant effects (p < 0.01) of fruit & fruit juice consumption frequencies, MNA (mini-nutritional assessment), cognition score, BMI, body fat %, waist circumference, arm circumference, calf circumference, vitamin D level that subjects who likes low salty taste were higher than subjects who likes high salty taste. Conclusions: The preference for salty taste in the elderly was not correlated with hypertension. But, increased preference for salty taste with age and increased salty food preferences may result in higher sodium consumption. Therefore, nutritional education regarding lowering salt preference and favorable behaviors of low-salt diet is needed to improve the quality of life in the rural elderly.

CDMA망에서 시스템 용량과 트래픽 부하의 변화를 반영한 핸드오프 영역 비율에 대한 성능분석 (Performance Analysis of Soft Handoff Region Ratio in CDMA System Considering System Capacity and Traffic Load)

  • 정성환;홍정완;이상천;이창훈
    • 산업공학
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    • 제20권2호
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    • pp.216-226
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    • 2007
  • In code-division multiple-access (CDMA) systems with soft handoff, mobile station (MS) within soft handoff region can use multiple radio channels and receive their signals from multiple base stations (BSs) simultaneously. In this paper, the effects of soft handoff region ratio (SHRR) on reverse link of a CDMA cellular system are analytically investigated. In order to analyze the network performance and quality of service (QoS) perceived by users more realistically, both the soft capacity increasing factor and the traffic load variation affected by SHRR are jointly considered and a two-dimensional continuous time Markov chain (CTMC) model is built. In the numerical example, it is observed that the optimal guard channel exists according the variations of the traffic load and propagation conditions when the proper value of SHRR is determined.

개발 웨이퍼 검사위한 Confocal 이미징 시스템의 개발 (Development of Confocal Imaging System for Wafer Inspection)

  • 고국원;다이 느엔 콩;고경철
    • 한국산학기술학회:학술대회논문집
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    • 한국산학기술학회 2010년도 춘계학술발표논문집 1부
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    • pp.108-112
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    • 2010
  • Confocal Imaging System is an essential machine for a wide range of inspection wafer. For concurrent and fast acquiring the image data of four channels, the new image acquisition system used the protocol of camera-link standard with the full mode of configuration in interconnection with a frame grabber integrated in a computer, which is popularly used for many cameras, so the programming environment of image processing is optional such as Visual C++, Matlab. In addition, many conventional methods were coordinately used for contribution to build the high quality of images for precise processing analog signals of PhotoMutiplier Tubes(PMTs), accurate control of scanning device, sensitivity of PMTs, and laser source. The prototype of new image acquisition system, could meet the goal of development, it is used in LSCM for high content screening to investigation the processes of elements of living specimens at the same time by simultaneous grab image data on 4 PMTs channels.

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PFC 기반의 서비스 복구 QoS 재라우팅 알고리즘에 관한 연구 (A Study on Service Recovery QoS Rerouting Algorithm Based on PFC)

  • 한정수;정진욱
    • 정보처리학회논문지C
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    • 제9C권5호
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    • pp.655-664
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    • 2002
  • 현재 QoS 라우팅의 목적은 사용자 서비스들의 각 QoS 요구사항을 만족하는 최적의 경로를 찾아 서비스하는 것이다. 그러나 네트워크 상황에 따라 장애가 발생했을 경우 이들의 QoS 요구를 만족시킬 수 있는 또 다른 백업 경로를 사용하여 서비스해야 한다. 따라서 본 논문에서는 네트워크 상에 발생된 장애 상황에 대해 서비스되고 있는 각 응용들에 대한 복구 방법으로 서비스 복구 QoS 재라우팅 알고리즘을 제시하고자한다. 이를 위해 사전에 모든 네트워크 노드를 보호할 수 있는 PFC(Protection Fundamental Cycle) 생성 방법론과 최소의 재라우팅 비용을 사용하는 경로 선택 알고리즘들에 대해 살펴보고 이들에 대한 성능을 분석하기로 한다.