• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.247-258
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• 2008

Environmental standards for beneficial uses of dredged materials are proposed. Even though chemical analysis of ocean sediments are carried out frequently, their analyses results were not interrelated with the effects of biological lives due to a shortage of biological data. These facts have resulted in difficulty to develope Korean's standards of recycling dredged materials. This paper first searched existing current foreign standards, analyzed local contaminated ocean sediment data, identified their main chemical components of contaminants, and then compared with clean-up standards of sediments consisting of lower and higher levels. From these analysis, new environmental standards considering Korean domestic circumstances are proposed. It is judged that new standards are appropriate to both Korean national sedimental environments and economically recycling aspects because environmental standard levels proposed are higher than background levels of sediments in Korean and foreign standards.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권11호
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• pp.4016-4027
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• 2014

Understanding network latency is important for providing consistent and acceptable levels of services in network-based applications. However, due to the difficulty of estimating applications' network demands and the difficulty of network latency modeling the management of network resources has often been ignored. We expect that, since network latency repeats cycles of congested states, a systematic classification method for network status would be helpful to simplify issues in network resource managements. This paper presents a simple empirical method to classify network status with a real operational network. By observing oscillating behavior of end-to-end latency we determine networks' status in run time. Five typical network statuses are defined based on a long-term stability and a short-term burstiness. By investigating prediction accuracies of several simple numerical models we show the effectiveness of the network status classification. Experimental results show that around 80% reduction in prediction errors depending on network status.

• 대한인간공학회지
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• 제29권6호
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• pp.943-949
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• 2010

When PCB soldering is performed with microscope due to the electronic components' microminiaturization, workers' awkward upper body postures and difficulties being in focus among lens, object and eyes are one of reasons for productivity decline. The object of this study is to investigate the level of difficulties of work and the extent of productivity improvement by changing work interfaces from the work using microscope to the work using LCD monitor. Independent variables was usage of microscope and image system and dependent variables were upper body segments including neck, shoulder, back, and waist, task convenience and eye fatigue. The Visual Analogue Scale (10cm) was used for questionnaire and one way ANOVA (two levels) and two sample t-test were conducted. In addition, RULA rating was conducted for working postures. The result showed that interface changes of LCD monitor, suggested by productivity comparison per one Man Hour, highly contributed to work convenience and productivity improvement.

• Journal of Acupuncture Research
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• 제20권1호
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• pp.1-12
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• 2003

Objectives : The purpose of this study is to compare Xingjian(LR2) Shaofu(HT8) with Dadun(LR1) Shaofu(HT8) on Blood Pressure in Hypertensive RAT induced by Two Kidney One Clip(2KIC). Methods : This experiments was to investigate the effects of LR2 HT8(originated from ${\ll}$Classic on Difficulty${\gg}$ Shi Ze Xie Qi Zi), LR1 HT8(originated from ${\ll}$Ling Shu${\gg}$ Sheng Ze Xie Zhi) acupuncture on the blood pressure, cardiomegalic index, and plasma levels of atrial natriuretic peptide in hypertensive rat induced by 2K1C. Results: 1. Blood pressure was decreased significantly after third acupuncture of LR2 HT8. 2. Blood pressure was decreased significantly after acupuncture of LR2 HT8, but was increased after LR2 HT8. 3. Cardiomegalic index was not changed after acupuncture of LR2-HT8 and LR1-HT8 4. Plasma levels of atrial natriuretic peptide was increased significantly after acupuncture of LR2 HT8 but LR1 HT8 was not changed.

• 한국환경생태학회지
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• 제29권4호
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• pp.626-635
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• 2015

최근 숲길 이용자들이 폭발적으로 증가하고 있으며, 이에 따라 각종 안전장치를 위한 비용 또한 급격히 증가하고 있다. 그럼에도 다른 사고와 달리 심장관련 사고는 줄지 않고 있어 숲길에 제공되는 난이도 정보의 개선방안에 대한 연구를 지리산 둘레길을 대상으로 진행하였다. 기존 숲길에 대한 난이도 정보는 숲을 관리하는 특정인에 의한 경험적 난이도 또는 단순히 거리를 바탕으로 한 난이도를 3~5단계로 구분하여 제공하고 있어 탐방객이 실제 느끼는 난이도와는 괴리감이 있었다. 본 연구에서는 실질적인 에너지소모량을 바탕으로 한 난이도 제공 가능성을 분석하였다. 거리와 경사에 따른 산소소모량의 계산은 숲길 각 구간에 대한 절대적 비교뿐만 아니라 상대적 비교가 가능하였으며 특정 구간의 운동강도를 간단히 표현하는데 효과적이었다. 아울러 시 종점의 변화에 따른 운동량 변화를 쉽게 확인할 수 있었다. 구간별, 산행방향별 운동량에 대한 표준화된 사전 정보제공은 심장관련 사고의 사전예방 효과가 있을 것으로 판단된다.

• 중국학논총
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• 제63호
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• pp.121-136
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• 2019

Graded reading is to match reading competency of readers with difficulty levels of text, based on the study of readability. This article discusses how to apply new media to develop Chinese graded reading materials which are more interesting, scientific and practical than traditional paper materials. The graded materials on the new media platform can be used for Chinese second language learners to self-study, and also for instructors to support reading and writing instruction in class or after class.

• 한국음향학회지
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• 제42권6호
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• pp.617-626
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• 2023

개방형 사무실에서 소음과 스피치 프라이버시 문제는 꾸준히 제기되어 왔다. 이러한 개방형 사무실의 문제점을 해결하기 위한 마스킹 음원에 대한 연구가 필요하다. 따라서 본 연구에서는 청취 실험을 통하여, 쾌적한 물소리를 마스킹 음원으로 제안하고자 한다. 먼저 다양한 소음 레벨에 대하여 음환경 쾌적도와 스피치 프라이버시를 고려한 최적 물소리 레벨에 대하여 고찰하고자 한다. 이후 최적 레벨의 물소리 도입이 업무효율성에 미치는 영향을 검정하고자 한다. 청취실험에서 사용된 사무실 소음은 실제 개방형 사무실에서 바이노럴 마이크를 활용해 녹음하였고, 헤드폰을 통해 피험자들에게 제시하였다. 청취실험 음원은 각각 3개의 등가 배경소음레벨(55 dBA, 60 dBA, 65 dBA)과 5개의 신호대잡음비[Signal to noise ratio(SNR) -10 dB, -5 dB, 0 dB, +5 dB, +10 dB]의 조합로 구성하였고, 각 음원에 대한 주관평가로 전체적인 음환경 쾌적도(Overall Soundscape Quality, OSQ)와 듣기 어려운 정도(Listening Difficulty, LD)를 평가하였다. 평가 결과 배경음 보다 물소리가 커질수록 LD는 증가하였지만 OSQ는 감소하였다. 특히 물소리가 사무실 소음 보다 클경우 도입 전보다 OSQ가 감소하였다. 따라서 OSQ와 LD를 고려하였을 때 소음레벨별 최적 SNR은 모든 소음레벨에 대하여, -5 dB로 나타났다. 이후 업무 효율성을 평가하기 위하여, 최적 레벨의 물소리 도입 전후에 인지능력(Cognitive performance)을 평가하였다. 평가 결과 최적 레벨의 물소리를 도입할 경우, 배경소음이 55 dBA에서는 인지능력평가 결과가 물소리 도입 전에 비해 감소하는 것으로 나타났으나, 60 dBA와 65 dBA에서는 증가하는 것으로 나타났다.

• 대한가정학회지
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• 제38권7호
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• pp.103-116
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• 2000

The purpose of this study was to find out the psychological characteristics of the unemployed, and their children's negative emotions and behavioral changes in the context of the increasing family dysfunction caused by the IMF economic crisis. The subjects were 184 public labor workers in Busan. They answered the questions about the psychological characteristics of themselves and their children, and their children's behavioral changes. Frequency analysis, $\chi$$^2$ test and logistic regression were used for data analyses. The results were as follows. The unemployed showed high levels of negative emotions and perceived their social supports as low. As well, they interpreted their quality of life as poor. They perceived their economic difficulty as high and the perception was influenced by negative emotions as well as the economic situation. Children of the unemployed showed middle levels of negative emotions, and positive and negative behavioral changes. These changes were influenced by their parent's psychological characteristics. In light of these results, psychological counseling services from social welfare centers are needed to be more actively supporting the families of the unemployed.

• 한국공작기계학회논문집
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• 제17권3호
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• pp.128-132
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• 2008

The noise levels and individual employee noise exposure levels within a factory will determine the need for hearing conservation program. The difficulty in not having an effective hearing conservation program is the risk of hearing loss that employees may sustain. In the last few years the claims for hearing loss compensation have grown due to class action litigation brought against the employer and companies that have equipment in the factory alleged to have caused hearing loss. The Blower in the factory generates the noise of 98.3dB(A) in the frequency range of 2,000Hz, which may cause occupational hearing loss. By designing close type enclosures which are made of absorption material, about 24.4dB(A) reduction has been in the factory. It is demonstrated that this kind of enclosures can be effectively used to reduce the noise in the factory.

• 한국과학교육학회지
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• 제5권1호
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• pp.11-17
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• 1985

This study had its objective to indentify the basic biological concepts as recommended by scholars in biology and by high school biology teachers for inclussion in the high school biology curriculum and to determine the importance levels of the concepts. The scholars for this study were selected to insure that their majors are evenly distributed across the biological areas. The final concept list contains 137 biological concepts along with their importance level judged by the scholars and high school biology teachers. The biological concepts are categorized into 12 biological areas. This study suggests that the concepts in the final list can not refect the conceptual hierarchy or inclusiveness, goals or objectives of biology education in the high school, and difficulty levels of the concepts. This study also claims that the concept list like the one produced by this study should be successively' checked and revised due to the continuous development of biological knowledge system and the constant change in the meanings of the knowledge system.