• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2000년도 추계학술발표논문집 (상)
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• pp.801-804
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• 2000

최근들어 암호기술은 급속도로 확산되고 있으며, 암호 사용으로 인한 부작용을 방지하기 위한 대안으로 키 복구에 대한 연구가 활발히 진행되고 있다. 그러나 지금까지 제시된 기존의 키 연구 기술들은 그 대부분이 정부의 법 집행권 보장에만 설계 초점을 맞추고 있기 때문에 다양한 사용자들의 요구를 충족시키기 어렵다. 본 논문에서는 키 복구 시스템에 대한 사용주체들의 입장을 고려하여 다양한 환경에 적용한 수 있는 키 복구 시스템을 제안한다. 제안하는 방식은 암호통신 과정 중에 키가 분배되는 일방향키 분배가 가능하고 기존 키 복구 시스템만큼 효율적이면서도 충분한 유연성을 제공한다.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 1999년도 가을 학술발표논문집 Vol.26 No.2 (3)
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• pp.288-290
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• 1999

현재 국내에서는 암호이용에 대한 법 제정을 가지고 많은 문제들이 제기되고 있다. 일반인에게 암호의 사용은 피상적이지만, 일부 선진국에서는 전자상거래 및 인터넷에서의 암호사용에 대하여 구체화시켜 실행하는 단계에 이르고 있다. 그러나, 이러한 암호 선진국에 있어서도 암호의 양면성, 즉 암호의 기밀성을 통한 개인정보와 기업정보 등을 포함하는 데이터의 보호와 범죄의 은닉에 사용될 수 있다는 문제를 가지고 있으며, 이에 대한 해결책으로 키 복구 방법을 사용하고 있다. 그런, 키 복구 방법은 개인의 인권 침해라는 새로운 문제를 대두시켰으며, 암호선진국들은 인권보호단체와 민간단체 그리고 기업의 반발에 의하여 키 복구 방법에 대한 새로운 서비스를 제공하고 있다. 국내에서도 연구 및 개발은 미비하지만 키 복구로 인하여 암호이용에 대한 법 제정이 지연될 정도로 전자상거래에 있어서, 그 비중이 크다고 할 수 있다. 본 논문에서는 키 복구 서비스를 사용하면서, 개인의 인권을 보호할 수 있는 키 복구 시스템을 소개한다.

• 한국자동차공학회논문집
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• 제10권2호
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• pp.101-116
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• 2002

Modern vehicles require a high degree of refinement, including good driveability to meet customer demands. Vehicle driveability, which becomes a key decisive factor for marketability, is affected by many parameters such as engine control and the dynamic characteristics in drive lines. Therefore, Engine and drive train characteristics should be considered to achieve a well balanced vehicle response simultaneously. This paper describes analysis procedures using a mathematical model which has been developed to simulate spark timing control logic. Inertia mass moment, stiffness and damping coefficient of engine and drive train were simulated to analyze the effect of parameters which were related vehicle dynamic behavior. Inertia mass moment of engine and stiffness of drive line were shown key factors for the shuffle characteristics. It was found that torque increase rate, torque reduction rate and torque recovery timing and rate influenced the shuffle characteristics at the tip-in condition for the given system in this study.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2003년도 추계학술발표논문집 (하)
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• pp.1965-1968
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• 2003

이동성과 편리성을 제공하는 이동 통신 환경은 다양한 장점을 가지고 있는 반면 무선이라는 특성상 보안에 대하여 취약하다. 따라서 기밀성과 인증 기능을 제공하는 다양한 암호 시스템 사용이 필요하게 되었으며, 암호의 역기능을 방지하기 위한 키 복구 기능이 포함된 다양한 키 분배 프로토콜이 제안되었다. 본 논문에서는 이동 통신 환경에 적합하게 설계된 키 복구 기능을 가진 키 분배 프로토콜에 대하여 분석하고, 이를 토대로 키 분배 프로토콜 설계 원칙을 제시하였다. 또한 제시한 설계 원칙을 기반으로 키 복구 기능을 가진 키 분배 프로토콜을 제안하였다.

• Journal of Microbiology and Biotechnology
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• 제17권1호
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• pp.146-153
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• 2007

A mathematical competition model between normal flora and an invading pathogen was devised to allow analysis of bacterial infections in a host. The normal flora includes the various microorganisms that live on or within the host and act as a primary human immune system. Despite the important role of the normal flora, no mathematical study has been undertaken on models of the interaction between it and invading pathogens against a background of antibiotic treatment. To quantify key elements of bacterial behavior in a host, pairs of nonlinear differential equations were used to describe three categories of human health conditions, namely, healthy, latent infection, and active infection. In addition, a cutoff value was proposed to represent the minimum population level required for survival. The recovery of normal flora after antibiotic treatment was also included in the simulation because of its relation to human health recovery. The significance of each simulation parameter for the bacterial growth model was investigated. The devised simulation showed that bacterial proliferation rate, carrying capacity, initial population levels, and competition intensity have a significant effect on bacterial behavior. Consequently, a model was established to describe competition between normal flora and an infiltrating pathogen. Unlike other population models, the recovery process described by the devised model can describe the human health recovery mechanism.

• 한국응용과학기술학회지
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• 제40권6호
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• pp.1340-1349
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• 2023

Despite its profound impact on athletic performance, the significance of heart rate recovery (HRR) has been insufficiently addressed in the filed of sports science, particularly in the context of weightlifting characterized by brief and intense exertions involving heavy weights. Serving as a valuable indicator of autonomic nervous system and cardiovascular function, HRR assumes a pivotal role in weightlifting. This comprehensive review aims to delineate the specific demands for HRR in weightlifting, shedding light on the often overlooked cardiovascular considerations within training regimes focused on strength and power. The investigation scrutinizes the repercussions of HRR on weightlifting performance, seeking to elucidate how inadequate recovery intervals may result in physiological and psychological consequences. These consequences encompass a distorted perception of effort, disruption of coordination, compromised posture due to irregular breathing, and an overall decline in lifting capacity. The review systematically presents compelling evidence pertaining to heart rate response and recovery patterns during weightlifting, underscoring the critical importance of well-structured rest periods. Furthermore, the review delves into a comprehensive discussion of factors influencing HRR in weightlifting, encompassing variables such as sex, age, cardiovascular function, hydration, nutrition, and psychological aspects. Finally, a key emphasis is placed on the integration of effective HRR techniques into the training regimens of weightlifters, thereby ensuring sustained and optimized performance outcomes.

• Nuclear Engineering and Technology
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• 제36권5호
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• pp.430-449
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• 2004

A quantitative model for a control system that integrates human operators, systems, and their interactions is developed based on discrete functions. After identifying the major entities and the key factors that are important to each entity in the control system, a quantitative analysis to estimate the recovery failure probability from an abnormal state is performed. A numerical analysis based on assumed values of related variables shows that this model produces reasonable results. The concept of 'relative sensitivity' is introduced to identify the major factors affecting the reliability of the control system. The analysis shows that the hardware factor and the design factor of the instrumentation system have the highest relative sensitivities in this model. T도 probability of human operators performing incorrect actions, along with factors related to human operators, are also found to have high relative sensitivities. This model is applied to an analysis of the TMI-2 nuclear power plant accident and systematically explains how the accident took place.

• 한국정보통신학회논문지
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• 제5권3호
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• pp.419-425
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• 2001

이동통신에서 다중경로에 의한 페이딩 현상은 시스템의 성능에 영향을 주는 큰 원인 중의 하나이다. 이런 페이딩 채널에서의 성능저하를 개선하기 위하여 많은 연구가 진행되고 있다. 채널 페이딩을 추정하여 보상하는 방식에서는 파일럿 심벌을 이용하는 PSAM(pilot symbol assisted modulation) 방식이 널리 이용되고 있으며 TCM(trellis-coded modulation)은 전송 대역폭의 증가 없이 철저한 부호화 이득을 얻을 수 있는 부호화와 변조 과정이 결합된 전송 기술이다. 본 논문에서는 주파수 비선택적 레일리 페이딩 채널에서 PSAM과 TCM을 사용하는 PSA-TC-8PSK의 성능을 분석하였다. 페이딩의 추정을 위한 보간 방법에는 오차의 분산을 최소화하는 Wiener 필터를 사용하였으며 필터의 탭수, 파일럿 심벌 주기, 도플러 주파수가 성능에 미치는 영향을 분석하였다. 또한 완전 디지털 방식의 구현이 가능한 심벌 타이밍 복구 회로를 구성하여 심벌 타이밍 에러가 전체 성능에 미치는 영향을 분석하였다.

• 한국물환경학회지
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• 제21권3호
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• pp.256-262
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• 2005

The purpose of this study is to investigate the performances of organic removal and methane recovery by using a full scale two-phase anaerobic system. The full scale two-phase anaerobic process was consists of an acidogenic anaerobic baffled reactor (ABR) and a methanognic upflow anaerobic sludge blanket (UASB) reactor. The volumes of acidogenic and methanogenic reactors were designed to $28.3m^3$ and $75.3m^3$. The two-phase anaerobic system represented 60-82% of COD removal efficiency when the influent COD concentration was in the range of 7,150 to 16,270 mg/L after screening (average concentration is 10,280 mg/L). After steady-state, the effluent COD concentration in the methanogenic reactor showed $2,740{\pm}330 mg/L$ by representing average COD removal efficiency was $71.4{\pm}8.1%$ when the operating temperature was in the range of $19-32^{\circ}C$. The effluent SCOD concentration was in the range of 2,000-3,000 mg/L at the steady state while the volatile fatty acid concentration was not detected in the effluent. Meanwhile, the COD removal efficiency in the acidogenic reactor showed less than 5%. The acidogenic reactor played key roles to reduce a shock-loading when periodic shock loading was applied and to acidify influent organics. Due to the high concentration of alkalinity and high pH in the effluent of the methanogenic reactor, over 80% of methane in the biogas was produced consistently. More than 70% of methane was recovered from theoretical methane production of TCOD removed in this research. The produced gas can be directly used as a heat source to increase the reactor temperature.

• ETRI Journal
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• 제42권5호
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• pp.748-760
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• 2020

MapReduce is a framework that can process huge datasets in parallel and distributed computing environments. However, a single machine failure during the runtime of MapReduce tasks can increase completion time by 50%. MapReduce handles task failures by restarting the failed task and re-computing all input data from scratch, regardless of how much data had already been processed. To solve this issue, we need the computed key-value pairs to persist in a storage system to avoid re-computing them during the restarting process. In this paper, the task failure resilience (TFR) technique is proposed, which allows the execution of a failed task to continue from the point it was interrupted without having to redo all the work. Amazon ElastiCache for Redis is used as a non-volatile cache for the key-value pairs. We measured the performance of TFR by running different Hadoop benchmarking suites. TFR was implemented using the Hadoop software framework, and the experimental results showed significant performance improvements when compared with the performance of the default Hadoop implementation.