• 센서학회지
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• 제26권5호
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• pp.297-300
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• 2017

Realistic media comprised of metadata of the five senses to provide enhanced experiences by stimulating our memory and sensations have had an increasingly pervading effect in our daily lives. Many researchers and companies are in the process of developing their own authoring systems running on different platforms to serve realistic media, resulting in compatibility issues among the systems. To tackle these issues, the International Organization for Standardization have standardized the interface, data format, protocol, API, etc. required to provide the realistic media. In particular, the ISO/IEC 23005 standard, which is called MPEG-V in SC29/WG 11, has defined XML schemas for olfaction interaction based on electronic nose (E-Nose), and scent display. In this paper, the MPEG-V standard for olfaction interaction is reviewed, and a data flow diagram that can be used for olfactory interaction based on the MPEG-V standard was designed. In addition, the necessary schemas related to the E-Nose sensor for olfactory interaction was provided.

• 한국농공학회지
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• 제45권2호
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• pp.107-115
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• 2003

Dairy manure amended with crop and forest residues (moisture 69% wet basis, C/N 22) was composted in a 605 L pilot-scale vessel using continuous air flow (56 L/min) for 19 days. Three pilot-scale sawdust biofilters (moisture 63%, pH 5.0) were built to clean biological waste gas from the composting process. For each methods, two replicated experiments were monitored over a period of three weeks. The system was evaluated to determine the biofilter media depth that would be adequate for compost odour reduction. The compost air cleaning was measured based on ammonia gas concentration before and after passing through the biofilter. Ammonia gas removal efficiency over 3 weeks was 42, 75 and 87% at sawdust biofilter media depth levels of 202, 400 and 600 mm, respectively. Each sawdust biofilter was operated at a moisture content in the range of 60~62% (wb), a temperature from 15 to $25^{\circ}C$, an average pressure drop from 240 to 340 Pa and a detention time from 60 to 180 seconds during the biofiltration process.

• 한국연소학회지
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• 제18권2호
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• pp.1-7
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• 2013

Flame stabilization characteristics of premixed flames in narrow annular coaxial tubes (NACT) were investigated experimentally. The NACT burner was proposed as a model of a cylindrical refractory burner, and it was made of quartz tubes. Flame stabilization conditions affected by the characteristic length of the burner was investigated with the variation of the equivalence ratio and the flow rates. Flame behaviors in narrow spaces could be directly observed. Conclusively, more wide flame stabilization conditions could be obtained at the case of the decreased channel scale. A flame instability, such as combustion noise was detected concerned with the flame oscillation observed at the surface of multi channel stage. Some flame propagation characteristics had complicated tendencies that may exist in practical porous-media combustors. Therefore, this NACT burner can be a basic configuration for the development of flame stabilization model in porous media combustor, and it will enhance our understanding about the behavior of flames in meso-scale combustion spaces.

• Advances in environmental research
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• 제6권1호
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• pp.35-51
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• 2017

The use of Granular Activated Carbon (GAC) and naturally occurring silica (Sand) as filtration media in water and waste water treatment systems is very common. While GAC offers the additional functionality of being an "adsorptive" filter for dissolved organics it is also more expensive. In this paper we present an experimental evaluation of the performance of a bed of GAC for colloid removal and compare the same with that from an equivalent bed of Sand. The experiments are performed in an "intermittent" manner over extended time, to "simulate" performance over the life of the filter bed. The experiments were continued till a significant drop in water flow rate through the bed was observed. A novel "deposition" and "detachment" rate based transient mathematical model is developed. It is observed that the data from the experiments can be explained by the above model, for different aqueous phase electrolyte concentrations. The model "parameters", namely the "deposition" and "detachment" rates are evaluated for the 2 filter media studied. The model suggests that the significantly better performance of GAC in colloid filtration is probably due to significantly lower detachment of colloids from the same. While the "deposition" rates are higher for GAC, the "detachment" rates are significantly lower, which makes GAC more effective than sand for colloid removal by over an order of magnitude.

• 한국산업보건학회지
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• 제24권2호
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• pp.201-207
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• 2014

Objectives: Flow rate stability is very important for obtaining reliable measurements. However there is no easily used method for checking whether the flow rate set at the initial stage is sustained during sampling. The purpose of this study was to develop a method to evaluate the flow rate performance of gas sampling pumps with adsorbents commonly used to sample gases. Materials and methods: We tested the back pressure of gas sampling pumps commonly used in Korea with adsorbents such as charcoal and silica tubes and attempted to discover the combination conditions of adsorbents in accordance with back pressure required by ISO standard 13137. Results: We found the combination of sampling adsorbents to be applicable to the pressure drop required by the ISO standard for evaluating flow rate stability under increasing pressure drop and long term (eight-hour) performance. Conclusions: This evaluation method of using a sampling media matrix for checking flow rate stability as proposed by this study could be a highly useful tool for determining the reliability of the performance pumps before sampling.

• Asian Journal of Atmospheric Environment
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• 제11권2호
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• pp.107-113
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• 2017

This study describes (1) the impact of positive sampling artifacts caused by not only a filter-based sampling, but also a denuder-based sampling in the determination of particle-phase organic carbon (POC), (2) the effect of sample flow rate on positive artifacts, and (3) an optimum flow rate that provides a minimized negative sampling artifact for the denuder-based sampling method. To achieve the goals of this study, four different sampling media combinations were employed: (1) Quartz filter-alone (Q-alone), (2) quartz filter behind quartz-fiber filter (QBQ), (3) quartz filter and quartz filter behind Teflon filter (Q-QBT), and (4) quartz filter behind carbon-based denuder (Denuder-Q). The measurement of ambient POC was carried out in an urban area. In addition, to determine gas-phase OC (GOC) removal efficiency of the denuder, a Teflon filter and a quartz filter were deployed upstream and downstream of the denuder, respectively with varying sample flow rates: 5, 10, 20, and 30 LPM. It was found that Q-alone sampling configuration showed a higher POC than QBQ, Q-QBT, and Denuder-Q by 12%, 28%, and 23%, respectively at a sample flow rate of 20 LPM due to no correction for positive artifact caused by adsorption of GOC onto the filter. A lower quantity of GOC was collected from the backup quartz filter on QBQ than that from Q-QBT. This was because GOC was not in equilibrium with that adsorbed on the front quartz filter of QBQ during the sampling period. It is observed that the loss of particle number and mass across the denuder increases with decreasing sample flow rate. The contribution o f positive arti facts to POC decreased with increasing sample flow rate, showing 29%, 25%, and 22% for 10, 20, and 30 LPM, respectively. The 20 LPM turns out to be the optimum sample flow rate for both filter and denuder-based POC sampling.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2005년도 추계 학술대회 논문집
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• pp.134-142
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• 2005

지하매질에서 핵종이동현상을 가시적으로 관찰할 수 있는 실험실규모 실험장치를 개발하여 이동실험을 수행하였다. 이 실험장치는 $50{\times}50cm$ 규모 화강암과 아크릴상층부로 구성되어있다. 실험에는 삼중수소, 음이온, 수착성양이온 뿐만 아니라 이동경로를 관찰할 수 있는 유기염료도 포함하였다. 시간에 따른 물질이동양태를 사진을 찍어 컴퓨터에 저장하였다. 또. 이동과정을 모사하고 단위공정별로 분석해 볼 수 잇는 이동모델도 개발하였다. 컴퓨터모사를 통해 균열내 흐름장에서 압력과 유속분포를 계산하고, 균열내 이동양태와 유출곡선을 계산해 실험결과와 비교 평가하였다.

• 한국게임학회 논문지
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• 제17권2호
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• pp.165-174
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• 2017

본 연구는 건강 기능성 게임인 흡연시뮬레이션 게임의 몰입을 결정하는 요인에 대해 파악하고 이들 요인들이 몰입에 어떠한 영향을 미치는지 분석하였다. 특히 게임 중에 발생하는 뇌 활동 패턴이 게임몰입과 어떠한 상관관계를 가지는지 뇌파측정과 몰입과의 관계를 규명하고자 하였다. 이를 위해 게임몰입의 정도를 종속변인으로 설정하고 몰입에 영향을 미칠 수 있는 감정이입, 건강관심도, 생리적 지표인 뇌파(${\alpha},{\beta}$)를 독립변인으로 설정하여 회귀분석을 실시하였다. 연구결과 흡연시뮬레이션 게임에서 몰입에 감정이입, 건강관심도, ${\beta}$파는 정적으로 영향을 미치고 있었으며, ${\alpha}$파의 경우 부적으로 영향을 미치고 있음이 확인되었다. 본 연구는 기능성 게임몰입에 영향을 미칠 수 있는 사용자 경험과 신경생리학적 변화에 대하여 자기 보고와 더불어 뇌파측정을 통해 실증적으로 분석하고 게임몰입의 결정요인을 규명하고 있다는 점에서 이론적 의미가 있다.

• 대한기계학회논문집B
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• 제41권4호
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• pp.229-238
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• 2017

본 연구는 다양한 기하학적 특성을 갖는 다공성 매질의 투과도를 유동조건의 변화와 상관없이 적절히 해석할 수 있는 일반화된 투과도 관계식을 도출하고자 시작되었다. 이에 우선, Darcy-Weisbach 관계식 (Darcy's 마찰유동관계식)의 다공질 유동에의 적용방안을 검토하였다. 결과적으로, Kozeny와 Carman 등의 선행연구를 바탕으로, Darcy-Weisbach 관계식은 다공질 유동해석에 적용이 가능하도록 확장되었다. 또한, 이는 모세관 유동모델을 바탕으로 마찰등가투과도(FEP)로 다시 정의되었다. 이때, 도출된 관계식의 유효성은 Kozeny-Carman 방정식과의 비교를 통해 검증되었고, 제시된 FEP 관계식이 Kozeny-Carman 방정식의 일반화된 형태임도 확인하였다. 결론적으로, 본 연구에서는 Darcy-Weisbach 관계식을 다공질 유동해석에 적용할 수 있도록 적절히 확장하고, 새로운 투과도 산정을 위한 FEP 관계식을 제시하였다.

• 자원환경지질
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• 제28권5호
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• pp.503-512
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• 1995

2차원 불연속 절리 모델 (Discrete Fracture Model)을 사용하여 절리망 내에서 지하수 흐름을 시뮬레이션하였다. 불연속 절리 모델에서는 지하수가 오직 절리망을 통해서 흐른다고 가정한다. 이와 같은 분석은 결정질암 같이 지질 매체의 투수율이 매우 낮은 경우에 유용하다. 하지만 불연속 절리망을 완벽하게 구현하는 것이 불가능하므로, 이에 접근하는 방법으로 확률 통계적 모델이 제안되었다. 확률-통계적 모텔은 특성인자(밀도, 방향, 길이, 틈새두께 등)가 특별한 분포 유형을 갖는다고 가정한다. 확률-통계적 모델은 가정된 분포를 따르도록 특성인자를 생성한다. 이 후 본 모델을 통해 분석된 몇몇 특성인자를 가지고 절리망을 생성한다. 절리망을 생성한 이 후 지하수의 유통을 계산하기 위해 유한요소법을 적용하였다. 이 때 일차원 선요소가 유한요소망의 주요 요소이다. 시뮬레이션 결과는 절리망 내의 주요 흐름 경로를 통해 보여진다. 절리망 내의 지하수 속도를 비교하여 주요 흐름 경로를 찾아낸다. 본 연구에서 개발된 모델은 절리망 내의 지하수 흐름에 특성인자들이 미치는 영향을 평가할 수 있는 방법을 제공한다. 이를 위하여 30번의 생성을 하는 몬테카를로 시뮬레이션을 통해서 여러 특성 인자들이 지하수 흐름에 미치는 영향을 평가하였다.