• BMB Reports
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• v.48 no.4
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• pp.209-216
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• 2015

Stress is now recognized as a universal premorbid factor associated with many risk factors of various chronic diseases. Acute stress may induce an individual's adaptive response to environmental demands. However, chronic, excessive stress causes cumulative negative impacts on health outcomes through "allostatic load". Thus, monitoring the quantified levels of long-term stress mediators would provide a timely opportunity for prevention or earlier intervention of stressrelated chronic illnesses. Although either acute or chronic stress could be quantified through measurement of changes in physiological parameters such as heart rate, blood pressure, and levels of various metabolic hormones, it is still elusive to interpret whether the changes in circulating levels of stress mediators such as cortisol can reflect the acute, chronic, or diurnal variations. Both serum and salivary cortisol levels reveal acute changes at a single point in time, but the overall long-term systemic cortisol exposure is difficult to evaluate due to circadian variations and its protein-binding capacity. Scalp hair has a fairy predictable growth rate of approximately 1 cm/month, and the most 1 cm segment approximates the last month's cortisol production as the mean value. The analysis of cortisol in hair is a highly promising technique for the retrospective assessment of chronic stress. [BMB Reports 2015; 48(4): 209-216]

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.304-306
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• 2005

아키텍쳐(Architecture)는 프로젝트 초기에 결정된 설계 결정사항을 기재해 놓은 산출물이고 프로젝트 관련자(Stakeholder)간 의사소통의 수단이다. 아키텍쳐가 안정되어야 향후 진화(Evolution) 과정 중에 시스템을 이해하고 예측 관리하는 것이 쉬워지고 또한 기본 구조를 변경하지 않고 여러 가지 기능을 추가할 수 있다. 아키텍쳐 안정성(Architecture Stability)이란 진화과정 중에 발생하는 변경들을 견디는 정도를 말하고 변경은 적응변경(Adaptive Changes), 교정변경(Corrective Changes), 완전변경(Perfective Changes )을 포함한다. 그런데 진화 과정 동안에 변경들은 필연적으로 발생하게 되고 그로 인해 결정된 아키텍쳐는 본래의 모습을 그대로 유지할 수 없게 된다. 따라서 진화 과정시 아키텍쳐의 안정성을 측정하고 향후 변경에 대한 대비가 필요하다. 본 논문은 변경의 크기, 변경의 횟수, 변경의 종류와 아키텍쳐 불안정성의 관계를 버전별로 연구하고 그와 관련된 매트릭을 제안한다. 매트릭을 실제 프로젝트(Ant,JDT)에 적용하고 측정된 결과를 통해 아키텍쳐 안정성을 살펴봄으로써, 향후 안정성을 고려하여 아키텍쳐를 관리하고 개발하는데 도움을 줄 수 있을 것이다.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11
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• pp.3097-3107
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• 1999

Recently many studies have been done on the Random Early Detection(RED) algorithm as an active queue management and congestion avoidance scheme in the Internet. In this paper we first overview the characteristics of RED and the modified RED algorithms in order to understand the current status of these studies. Then we analyze the RED dynamics by investigating how RED parameters affect router queue behavior. We show the cases when RED fails since it cannot react to queue state changes aggressively due to the deterministic use of its parameters. Based on the RED parameter analysis, we propose a self-adaptive algorithm to cope with this RED weakness. In this algorithm we make two parameters be adjusted themselves depending on the queue states. One parameter is the maximum probability to drop or mark the packet at the congestion state. This parameter can be adjusted to react the long burst of traffic, consequently reducing the congestion disaster. The other parameter is the queue weight which is also adjusted aggressively in order for the average queue size to catch up with the current queue size when the queue moves from the congestion state to the stable state.

• Journal of Information Technology Services
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• v.14 no.1
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• pp.99-113
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• 2015

Adaptive bitrate (ABR) streaming technology has become an important and prevalent feature in many multimedia delivery systems, with content providers such as Netflix and Amazon using ABR streaming to increase bandwidth efficiency and provide the maximum user experience when channel conditions are not ideal. Where such systems could see improvement is in the delivery of live video with a closed loop cognitive control of video encoding. In this paper, we present streaming camera system which provides spatially and temporally adaptive video streams, learning the user's preferences in order to make intelligent scaling decisions. The system employs a hardware based H.264/AVC encoder for video compression. The encoding parameters can be configured by the user or by the cognitive system on behalf of the user when the bandwidth changes. A cognitive video client developed in this study learns the user's preferences (i.e. video size over frame rate) over time and intelligently adapts encoding parameters when the channel conditions change. It has been demonstrated that the cognitive decision system developed has the ability to control video bandwidth by altering the spatial and temporal resolution, as well as the ability to make scaling decisions

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.10
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• pp.4929-4947
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• 2017

In visual object tracking, Correlation Filter-based Tracking (CFT) systems have arouse recently to be the most accurate and efficient methods. The CFT's circularly shifts the larger search window to find most likely position of the target. The need of larger search window to cover both background and object make an algorithm sensitive to the background and the target occlusions. Further, the use of fixed-sized windows for training makes them incapable to handle scale variations during tracking. To address these problems, we propose two layer target representation in which both global and local appearances of the target is considered. Multiple local patches in the local layer provide robustness to the background changes and the target occlusion. The target representation is enhanced by employing additional reversed RGB channels to prevent the loss of black objects in background during tracking. The final target position is obtained by the adaptive weighted average of confidence maps from global and local layers. Furthermore, the target scale variation in tracking is handled by the statistical model, which is governed by adaptive constraints to ensure reliability and accuracy in scale estimation. The proposed structural enhancement is tested on VTBv1.0 benchmark for its accuracy and robustness.

• Journal of Platform Technology
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• v.6 no.3
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• pp.38-46
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• 2018

Smart Grid is an intelligent power grid for efficiently producing and consuming electricity through bi-directional communication between power producers and consumers. As renewable energy develops, the share of renewable energy in the smart grid is increasing. Renewable energy has a problem that it differs from existing power generation methods that can predict and control power generation because the power generation changes in real time. Applying a self-adaptative framework to the Smart Grid will enable efficient operation of the Smart Grid by adapting to the amount of renewable energy power generated in real time. In this paper, we assume that smart villages equipped with photovoltaic power generation facilities are installed, and apply the self-adaptative framework, AiTES, to show that smart grid can be efficiently operated through self adaptation framework.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.2 no.1
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• pp.59-64
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• 2009

In this paper, a novel low complexity linear receiver is proposed that is used at the receiver of MIMO systems. Zero-forcing (ZF) and minimum mean squared error (MMSE) receivers are common linear receivers. ZF receiver is simpler than MMSE receiver from the hardware implementation perspective, howerver, MMSE shows better performance than ZF. In general, MCS level changes according to channel condition. This paper shows the benefit of choosing between MMSE and ZF according to the selected MCS level. We implement the MCS-adaptive linear receiver as hardware, and show that its complexity is comparable to the conventional MMSE receiver.

• The Journal of Information Systems
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• v.16 no.1
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• pp.159-178
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• 2007

As generalization of using PC and the Internet information technology (IT) users in organizations are not passive clients but active producers of information services. One of the reasons for the change of users' role is social interactions with other users and IT department staffs. That is, users can find and develop new functions and usefulness of IT, especially, Web-based ones through communication with other users or IT department staffs. The objective of this study is to investigate the relationship between IT department service quality and social interactions with other users. For this purpose, we suggest a research model based on adaptive structuration theory (AST), which is to explain the changes in social structure (rules and resources) of IT by social interactions, as well as service quality theory. Our model's exogenous variable is service quality which is a second-order factor consisting of reliability, responsiveness, assurance, and empathy. As endogenous variables, we adopt two variables for appropriateness of using IT, faithfulness of appropriation and consensus on appropriation. Finally, dependent variables of ow model are usefulness and ease of use which can be considered as attitude on IT as well as other variables for appropriateness. For empirical test our model is applied to users of groupware and ERP in organizations and analyzed by partial least square. In result, all hypotheses suggested in our model are supported statistically.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.5
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• pp.649-658
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• 2008

In this paper, we proposed an adaptive PSO(APSO) algorithm which changes parameter values with every recursion based on the conventional particle swam optimization(CPSO). In order to solve the optimization problem, the proposed APSO algorithm is applied to some functions, such as the De Jong function, Ackley function, Davis function and Griewank function. The superiority of the proposed APSO algorithm compared with the genetic algorithm(GA) is proved through the numerical experiment. Finally we applied the proposed algorithm to developing a function for personal magnetic field exposure based with real datas which are acquired based on the consumer research and field measuring instrument.

• Journal of Environmental Policy
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• v.5 no.4
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• pp.19-49
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• 2006

As global climate change is expected to influence regional water resources, water resource managers need to establish adaptive management to cope with climate change. We examined adaptive management efforts in the US, UK, Canada, Australia, and the Netherlands. Each country is implementing different levels of adaptation efforts based on current water management practices, institutional arrangements, as well as the varying degree of water availability, current climate effects and expected climate change effects. Based on the comparison of these countries, we suggest policy implications for the sustainable water resource management of Korea under climate changes.