• International Journal of Air-Conditioning and Refrigeration
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• v.16 no.1
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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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.265-266
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• 2021

In this paper, we show the case of establishing a outdoor production system using the Internet of things and define the environmental variables in the outdoor production system. By measuring soil temperature, water content, electrical conductivity and acidity through sensors, LoRa communication module transmits the information to the outdoor production system. The outdoor production system controls the amount of fertilizer and the volume of water based on this sensor data. We have developed a system that manages a wide range of crops using LoRa technology, which is a suitable communication method for cultivating crops, and manages production volume and sales performance.

• The Journal of the Korea Contents Association
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• v.11 no.6
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• pp.215-227
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• 2011

Recently, City has contributed to the various and convenient environment by public design projects. These projects have grown very attentive to the outdoor signboards in cities. From this background, the local governments including the central government have driven to the outdoor signboards through the city street scenery improvement projects. These the outdoor signboards improvement projects are strengthen the city's aesthetic function and city street scenery. In this research, we surveyed the satisfaction level of the outdoor signboards for shop which were engaged in this project and citizen by t-test method. We surveyed 30 stores and 41 citizen for the outdoor signboard's aesthetic function, a reflection of region and store's properties and communication effects. From our results, we researched the various understanding and satisfaction of the outdoor signboards improvement projects. Stores owner and citizens did not satisfy the outdoor signboards improvement projects. From our research, in order to advertise the city's aesthetic function and to create our own unique outdoor signboards culture, a variety of tools and intensive cases are demanded, in the future the research on the outdoor signboards improvement projects must revitalized.

• Fashion & Textile Research Journal
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• v.19 no.6
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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.

• Journal of the Korean Applied Science and Technology
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• v.36 no.4
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• pp.1410-1419
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• 2019

In this research, it is to find a method that frost does not form on the outdoor unit to develop a heat pump capable of heating in cold regions. For this reason, we produced an incubator capable of creating an environment of -25℃, and constructed an experimental apparatus so that experiments in the room were possible. However, it is necessary to grasp the characteristics of the air reaching the front of the heat pump outdoor unit installed in the experimental apparatus, and flow analysis was performed using ANSYS CFX, which is general-purpose software. As a result, the flow velocity of the air reaching the front of the outdoor unit in the outdoor unit chamber in the entire region of the simulation conditions (5.0 to 7.5 m/s) has many differences in the upper and lower portions, resulting in a natural state. It turned out that the condition can not be satisfied. Therefore, it is determined that it is necessary to additionally install a frequency divider at the front of the outdoor unit to make the flow velocity constant.

• Korean Journal of Community Nutrition
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• v.20 no.2
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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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.8
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• pp.1655-1666
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• 2015

In this paper, user-position estimation method is proposed by using a single camera for both indoor and outdoor environments. Conventionally, the GPS of RF-based estimation methods have been widely studied in the literature for outdoor and indoor environments, respectively. Each method is useful only for indoor or outdoor environment. In this context, this study adopts a vision-based approach which can be commonly applicable to both environments. Since the distance or position cannot be extracted from a single still image, the reference images pro-stored in image database are used to identify the current position from the single still image captured by a single camera. The reference image is tagged with its captured position. To find the reference image which is the most similar to the current image, the SURF algorithm is used for feature extraction. The outliers in extracted features are discarded by using RANSAC algorithm. The performance of the proposed method is evaluated for two buildings and their outsides for both indoor and outdoor environments, respectively.

• Journal of the Korean Society of Safety
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• v.35 no.6
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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.

• Proceedings of the KIEE Conference
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• 2003.07d
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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.

• Proceedings of the Korean Environmental Health Society Conference
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• 2005.06a
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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.