• International Journal of Air-Conditioning and Refrigeration
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• 제16권1호
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• pp.15-21
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• 2008

Air-cooled split-type air conditioners (AC) are very popular in high-rise residential and commercial buildings in Korea. The performance of such AC systems varies significantly with system characteristics and environmental conditions. Particularly, the outdoor condensing unit of the system, if poorly cooled due to high density of AC distribution and restricted outdoor space, will result in large decrease of cooling efficiency and increase of electrical energy consumption and may further jeopardize the system reliability. This paper presents a numerical analysis on the thermal and energy performance of a group of air-cooled air conditioners installed at a courtyard of a high-rise building. The study introduces a series of new energy performance indices to assess the group performance of the AC condensers with different outdoor unit layouts. The results not only indicate the COP of the systems, but also quantify the system capacity and energy consumption. The evaluation method and indices developed are useful for guiding the design of the distribution plan of the AC units at building re-entrants.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 춘계학술대회
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• pp.265-266
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• 2021

본 논문은 사물인터넷을 이용한 노지 농작물 재배 시스템 구축 사례를 설명하고 노지 작물 재배 시스템에서의 환경 변수를 정의하였다. 다양한 센서을 통해서 토양의 온도, 함수율, 전기전도도, 산성도를 측정하여 LoRa 통신 모듈을 이용하여 서버로 정보를 전달하고, 서버는 이 데이터를 바탕으로 시비량 및 관수량을 제어한다. 노지 농작물 재배에 적합한 통신 방식인 LoRa 기술을 이용하여 넓은 노지를 관리하고 생산량 및 판매실적까지 관리하는 시스템을 개발하였다.

• 한국콘텐츠학회논문지
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• 제11권6호
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• pp.215-227
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• 2011

최근 들어 도시의 공공디자인을 통해 다양하고 편의적인 환경이 적용되고 있다. 그중 하나인 도심에 산재되어 있는 다양한 옥외 광고물들에 대한 관심이 높아져 가고 있다. 이러한 배경으로 정부를 비롯하여 각 지자체에서 도시가로환경을 개선하고자 하는 방향으로 간판정비사업을 실시하고 있다. 이러한 도심의 간판 정비사업은 도시의 심미적 기능을 고도화 시키고 도시가로환경의 정돈되고 활력 있는 모습을 제공하고자 노력하고 있다. 따라서 본 연구는 대전광역시의 간판정비사업을 수행한 지역을 선정하여 간판정비사업을 참여한 업체와 그 업체를 이용하는 일반 시민들의 만족도를 t-검정을 통해 조사하였다. 간판정비사업에 대한 만족도 조사는 업소 30개 및 일반 시민 41명을 대상으로 실시하였다. 조사 결과는 간판정비사업을 통해 간판의 심미적 기능에 대해서 만족도가 낮았으며, 지역 및 업소 특성의 반영 여부, 정보전달 효과 등에 대한 만족도가 낮게 나타났다. 업소뿐 만아니라 일반 시민들도 간판개선사업에 대한 인식 및 만족도가 낮게 나타났다. 이러한 내용을 바탕으로 추후 진행되는 간판개선사업 뿐만 아니라 도시문화를 창조하는 다양한 방안들이 제시되어야 하겠다. 앞으로 이러한 옥외간판에 대한 다양한 사례 연구와 심도 있는 연구가 지속되어야 하겠다.

• 한국의류산업학회지
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• 제19권6호
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• pp.736-748
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• 2017

This study was carried out to offer basic data that can be used for clothing industry for active senior males emerging as a new consumer bracket in the rapid aging age. To this end, this study conducted a questionnaire survey on consumers' wearing condition targeting active senior males. As a result of the questionnaire survey targeting active senior males, the outdoor wear items that they had the most were windbreaker jackets, long pants, and they said the most important reason for their preferred brand was wearing sensation. The matters to consider in purchasing outdoor wear were also wearing sensation and size. Consequently, the active senior males regard wearing sensation as very important. The measurements that they felt uncomfortable by body part were the abdominal extension circumference, sleeve length and jacket length of a jacket, and the rise and lengths of pants. To design the outdoor wear patterns suitable for the active senior male's body type, the pattern measurements of these body parts need to be modified. From the fact-finding survey result on outdoor wear companies, their measurement indicating method was the same for jackets, but each brand used different methods for pants. Based on the results of this survey, outdoor wear needs to be developed to meet active senior needs.

• 한국응용과학기술학회지
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• 제36권4호
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• pp.1410-1419
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• 2019

본 연구는 한냉지에서 실외기에 서리가 형성되지 않는 난방이 가능한 히트펌프를 개발하고자 한다. 그래서 실내에서 -25℃의 환경을 제공할 수 있는 항온기 및 실험챔버를 구성하였다. 실험장치 내에 설치된 히트펌프의 실외기 전면에 도달하는 공기의 특성을 파악할 필요가 있어 범용소프트웨어인 ANSYS CFX를 이용하여 유동해석을 하였다. 그 결과 시뮬레이션 조건(5.0~7.0 m/s)의 모든 영역에서 실외기 전방에 도달하는 공기의 유속이 자연상태와 다르게 분포함을 파악하였다. 따라서 실외기 전면에 일정한 공기 유속이 도달할 수 있도록 별도의 공기분배기를 추가 설치할 필요가 있다고 판단된다.

• 대한지역사회영양학회지
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• 제20권2호
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• pp.120-128
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• 2015

Objectives: The purpose of this study was to examine the relative impact of seasonal differences and age on dietary vitamin D intakes, outdoor activity time and serum vitamin D status among Korean postmenopausal women. Methods: A cross-sectional study was conducted with 164 free-living postmenopausal women (mean age=55.4 years) in Daegu, Korea. Dietary intake, daily physical activity patterns and fasting blood samples were collected during summer and winter. We compared the results from 75 women during summer and 89 women during winter. Dietary intake of vitamin D was assessed by 24-hour recall method. Daily outdoor activity time was derived from physical activity diary. Results: The average dietary intake of vitamin D of the participants was $3.7{\mu}g$ during summer, $3.3{\mu}g$ during winter, showing no significant difference between the two seasons. The average time spent on outdoor activities was not significantly different between summer ($=35.1{\pm}75.0min/d$) and winter ($=48.5{\pm}76.8min/d$). The average serum 25-(OH) vitamin D concentrations of participants was $17.5{\pm}7.5ng/mL$ in the summer and $13.4{\pm}4.3ng/mL$ in the winter, showing no significant differences by season. Dietary intake of vitamin D was not related to age. When total subjects were divided into two groups by age, the average serum 25-(OH) vitamin D concentration was significantly higher in older group (p=0.047) and time spent on outdoor activities was also (p=0.018) significantly higher in the older group. Conclusions: In order to improve the current vitamin D status of Korean postmenopausal women, nutrition education programs should focus more on adequate intake of vitamin D, while maintaining enough outdoor activities over the season.

• 한국통신학회논문지
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• 제40권8호
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• pp.1655-1666
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• 2015

본 논문에서는 Fingerprint 기법의 Resource로 신호의 세기가 아닌 이미지를 이용해 좌표정보를 포함하는 이미지 기반의 데이터베이스를 구축하고, 사용자로부터 입력되는 이미지와 유사도 비교를 통해 사용자의 위치추정 기법에 대해 제안한다. Fingerprint 기법은 신호 세기뿐만 아니라 환경에 대한 지역적 잡음 정보들까지 모두 추정에 반영하므로 높은 위치 추정 정확도를 제공한다. 이미지의 유사도는 SURF 알고리즘을 통해 데이터베이스와 사용자 입력 이미지의 특징점을 검출하고, 동일한 특징점 간의 매칭을 통해 비교된다. 여기에서 우리는 RANSAC 알고리즘을 함께 사용하여 검출된 특징점의 노이즈 제거를 통해 이미지 유사도 비교의 정확도를 높였다. 제안하는 기법의 검증을 위해 두 건물의 실내와 주변 실외 환경에서 이미지를 획득하여 데이터베이스를 구축하고, 임의의 위치에서 사용자의 위치를 추정하였다. 추정 된 최종 위치는 데이터베이스에 저장 된 이미지가 가지는 좌표가 사용자의 위치와 가장 근접한 좌표로 검출되는지 확인하였으며 RANSAC을 통해 특징점의 노이즈 제거 전과 제거 후에 대한 이미지 유사도 비교의 성능을 분석하였다.

• 한국안전학회지
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• 제35권6호
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• pp.15-24
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• 2020

With the development of the chemical industry, the chemical accident is increasing every year, thereby increasing the risk of accidents caused by chemicals. The Ministry of Environment provides the criteria for determining shelter-in-place or outdoor evacuation by material, duration of accident, and distance from the toxic substance leak. However, it is hard to say that the criteria for determining the transition point are not clear. Transition point mean the time that evacuation method is switched from shelter-in-place to outdoor evacuation. So, the purpose of this study was to calculate appropriate transition point by comparing the cumulative toxic load. Namdong-gu in Incheon Metropolitan City was finally selected as the target area, considering the current status of the population of Incheon Metropolitan City in 2016 and the statistical survey of chemicals in 2016. The target materials were HCl, HF, and NH₃. Modeling was simulated by ALOHA and performed assuming that the entire amount would be leaked for 10 min. Residents' evacuation scenarios were assumed to be shelter-in-place, immediate outdoor evacuation, and outdoor evacuation at an appropriate time after shelter-in-place. Based on the above method, the appropriate transition point from residents located in A(800 m away), B(1,200 m away), C(1,400 m away) and D(2,200 m away) was identified. In HCl, appropriate transition point was after 15 min, after 16 min, after 17 min, after 20 min in order by A, B, C and D. In HF, appropriate transition point was before 1 min or after 16 min, before 4 min or after 19 min, before 5 min or after 20 min, before 14 min or after 26 min in order by A, B, C and D. In NH₃, appropriate transition point at A was before 4 min or after 16. Others are not in chemical cloud. This study confirmed the transition point to minimize the cumulative toxic load can be obtained by quantitative method. Through this, it might be possible to select evacuation method quantitatively that cumulative toxic load are minimal. In addition, if the shelter-in-place is maintained without transition to outdoor evacuation, the cumulative toxic load will increase more than outdoor evacuation. Therefore, it was confirmed that actions to reduce the concentration of chemicals in the room were necessary, such as conducting ventilation after the chemical cloud passed through the site.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 D
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• pp.2358-2361
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• 2003

In this paper, parallel control method that enables coordinating operations of multiple mini ice storage air conditioner is proposed based on LonWorks system. The proposed parallel control method is a kind of master/slave control method based on LonTalk network communication. In the control method, master controller leading whole system operations is determined by date to avoid the disproportion of outdoor unit operations. In addition to the above, duty shift control method is proposed to avoid redundant operations of outdoor units and to equalize the operation frequencies of them. Through some simulation tests, the proposed parallel control method and the duty shift control method are evaluated and the efficiencies of them are validated by comparing with existing methods.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2005년도 국제학술대회
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• pp.293-298
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• 2005

Indoor air quality can be affected by indoor sources, ventilation, decay and outdoor levels. Although technologies exist to measure these factors, direct measurements are often difficult. The purpose of this study was to develop an alternative method to characterize indoor environmental factors by multiple indoor and outdoor measurements. Indoor and outdoor NO$_2$ and VOCs(benzene, toluene, xylene) concentrations were measured every 3 days for 60 consecutive days in 30 houses in Seoul, Asan and Daegu, Korea. Using a mass balance model and regression analysis, penetration factor (ventilation rate divided by the sum of ventilation rate and deposition constant) and source strength factor (source strength divided by the sum of ventilation rate and deposition constant) were calculated using multiple indoor and outdoor measurements. Subsequently, NO$_2$ and VOCs source strengths (ppb/hr) and deposition constant (K, hr$^{-1}$) were estimated. Deposition constants of NO$_2$, toluene and xylene were 0.98 ${\pm}$ 0.28, 0.71 ${\pm}$ 0.24 and 0.74 ${\pm}$ 0.53 hr$^{-1}$, respectively. Source strengths of NO$_2$, toluene and xylene were 16.28 ${\pm}$ 7.47,31.25 ${\pm}$ 38.45 and 23.45 ${\pm}$ 19.67 ppb/hr, respectively In conclusion, indoor environmental factors were effectively characterized by this method using multiple indoor and outdoor measurements.