• 한국지하수토양환경학회지:지하수토양환경
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• 제28권6호
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• pp.71-89
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• 2023

A groundwater potential map (GPM) was built for the Nakdonggang River Basin based on ten variables, including hydrogeologic unit, fault-line density, depth to groundwater, distance to surface water, lineament density, slope, stream drainage density, soil drainage, land cover, and annual rainfall. To integrate the thematic layers for GPM, the criteria were first weighted using the Analytic Hierarchical Process (AHP) and then overlaid using the Technique for Ordering Preferences by Similarity to Ideal Solution (TOPSIS) model. Finally, the groundwater potential was categorized into five classes (very high (VH), high (H), moderate (M), low (L), very low (VL)) and verified by examining the specific capacity of individual wells on each class. The wells in the area categorized as VH showed the highest median specific capacity (5.2 m³/day/m), while the wells with specific capacity < 1.39 m³/day/m were distributed in the areas categorized as L or VL. The accuracy of GPM generated in the work looked acceptable, although the specific capacity data were not enough to verify GPM in the studied large watershed. To create GPMs for the determination of high-yield well locations, the resolution and reliability of thematic maps should be improved. Criterion values for groundwater potential should be established when machine learning or statistical models are used in the GPM evaluation process.

• 한국산업보건학회지
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• 제16권4호
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• pp.364-374
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• 2006

Natural ventilation technique could be the substitute for or the complement to the local exhaust ventilation system in the sense of protecting work environment. Moreover, it has many strong points ; almost no mechanical parts, no energy use and no noise. If applied appropriately, it could have the very high ventilation rate and save a lot of energy expense. But, it depends on the outdoor environment, especially temperature and wind speed/direction. Predicting the capacity of natural ventilation is not an easy job because it comes from both buoyancy and wind effect. Another problem is too much flow through the ventilator especially in winter time due to too much difference between indoor and outdoor temperature. Thus some ventilators in industries are sealed by door or plastic sheet, resulting in bad work environment. Various types of dampers are used to control the flow rate through ventilators. The capabilities of flow control by damper has not been estimated. In addition, it was not tested whether the damper could obstruct the flow through ventilator when fully opened. To answer these questions, 4 types of dampers were tested by using computational fluid dynamics. 10 different configurations includes no damper, full open and half open. Flow rates were estimated and airflow fields were analysed to clarify the before-mentioned questions. The dual type damper was the best choice for controling the capability of ventilator. In addition, the upward grill type damper was the best for not obstructing the air flow when fully opened.

• Earthquakes and Structures
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• 제12권1호
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• pp.13-21
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• 2017

Recent seismic events occurred in Italy (Emilia-Romagna 2012, Abruzzo 2009) and worldwide (New Zealand 2010 and 2011) highlighted some of the weaknesses of precast concrete industrial buildings, especially those related to the connecting systems traditionally employed to fasten the cladding panels to the internal framing. In fact, one of the most commons fails it is possible to observe in such structural typologies is related to the out-of-plane collapse of the external walls due to the unsatisfactory behaviour of the connectors used to join the panels to the perimeter beams. In this work, the strengthening of a traditional industrial building, assumed as a case study, made by precast reinforced concrete is proposed by the adoption of a dual system allowing the reinforcement of the structure by acting both internally; by pendular columns and, externally, on the walls. In particular, traditional connections at the top of the walls are substituted by devices able to work as a slider with vertical axis while, the bottom of the walls is equipped with two or more hysteretic dampers working on the uplift of the cladding panels occurring under seismic actions. By means of this approach, the structure is stiffened; obtaining a reduction of the lateral drifts under serviceability limit states. In addition, its seismic behaviour is improved due to the additional source of energy dissipation represented by the dampers located at the base of the walls. The effectiveness of the suggested retrofitting approach has been checked by comparing the performance of the retrofitted structure with those of the structure unreinforced by means of both pushover and Incremental Dynamic Analyses (IDA) in terms of behaviour factor, assumed as a measure of the ductility capacity of the structure.

• 대한디지털의료영상학회논문지
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• 제15권1호
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• pp.39-45
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• 2013

PACS Import external image of the thread of the tasks and duties of hospital revenue and business efficiency falls over time. 500 beds or more medical imaging import work outside of the hospital, most hospitals use a PC, KIOSK, and was used in 15 hospitals where, CD Autoloader where use was the only one. Working hours compared to CD and DVD media to test the results of the Import target PC, KIOSK, CD Autoloader Import spent less time in the order, and also the greater capacity of CD Autoloader four times the PC, KIOSK 2 times Import could be implemented quickly. In addition, the waiting time of the patients was measured using the PC's time to Import, 2011 14.5 minutes and the average patient waiting time, KIOSK and later use CD Autoloader 2012 average patient wait time of 8.25 minutes, 43% of the existing average waiting time was 5.25 minutes to reduce. However, KIOSK case of a patient in a way that directly Import latency time was soon. Import of three ways: in terms of efficiency and excellent CD Autoloader way, the patient waiting time in terms of ease of use and KIOSK was excellent. In addition, with the introduction of CD Autoloader with KIOSK Joint of the items waiting time of patients and patient satisfaction rating is considered to be a major contribution.

• 농촌지도와개발
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• 제17권3호
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• pp.527-548
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• 2010

The objective of this study is to suggest the developmental tasks for the successful fostering the Farmer's Study Group which have been guided by the agricultural extension work since 1994 in Korea. The 3,278 farmers study groups with 148,420 memberships have been organized in field of grains, cash crop, horticulture, livestock, improving living conditions, food processing and so on. Although the number of study groups have rapidly expanded, there also are tasks to be secured for their successful development in terms of (a) desirable phase of the study groups and goals of its fostering, (b) managements / administration of them, (c) long-term tasks to be reviewed. With regard to the desirable phase of the study groups and goals of its fostering, they should secure differential mission and the way of works compare to the other farmer's groups. Also, there should be consensus on the proper number of study groups to be fostered with a agricultural technical center at local level. With regard to the managements / administration of the study groups, there should be the different support, assistance and guidance according to the developmental level of the groups. For these, there should be evaluation works on the groups, and guidance manuals for the extension workers. Also extension works should facilitate the establishment of networks among groups over the counties. Finally, to establish the nationwide association in hierarchy and to make the cooperative works with similar farmer's group, doing the value-added activities rather than mere information exchange, and the introduction of capacity building programs for the extension workers are long-term tasks needed to review for the successful fostering study groups.

• 산업경영시스템학회지
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• 제42권1호
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• pp.55-63
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• 2019

This paper develops an algorithm to determine the batch size of the batch process in real time for improving production and efficient control of production system with multiple processes and batch processes. It is so important to find the batch size of the batch process, because the variability arising from the batch process in the production system affects the capacity of the production. Specifically, batch size could change system efficiency such as throughput, WIP (Work In Process) in production system, batch formation time and so on. In order to improve the system variability and productivity, real time batch size determined by considering the preparation time and batch formation time according to the number of operation of the batch process. The purpose of the study is to control the WIP by applying CONWIP production system method in the production line and implements an algorithm for a real time batch size decision in a batch process that requires long work preparation time and affects system efficiency. In order to verify the efficiency of the developed algorithm that determine the batch size in a real time, an existed production system with fixed the batch size will be implemented first and determines that batch size in real time considering WIP in queue and average lead time in the current system. To comparing the efficiency of a system with a fixed batch size and a system that determines a batch size in real time, the results are analyzed using three evaluation indexes of lead time, throughput, and average WIP of the queue.

• 드라이브 ㆍ 컨트롤
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• 제21권2호
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• pp.23-29
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• 2024

Potatoes are one of the world's four major crops, and domestic consumption is currently increasing in Korea. However, the mechanization rate of potatoes is very low, and especially, harvesting is the most labor-intensive task in potato production. In Korea, potato-collecting work depends on manpower, so it is necessary to develop a gathering-type harvester that can be used for processes from digging to harvesting. Therefore, in this study, a self-propelled-type potato harvester was developed, and its performance was analyzed to mechanize harvesting. The potato harvester was developed to have a crawler-type driving part with a 60 hp diesel engine and consisted of a digging part that digs potatoes from the ground, a vertical transporting part that transfers the dug potatoes to the height of the collection bag, a separating part that separates debris, such as stones and soil, and a collecting part that loads the collection box. A field test of the potato harvester was conducted, and performance was evaluated by the damage, loss, and debris mixing proportions, which were 2.5%, 2.8%, and 2.6%, respectively. The working capacity was 1.2 h/10 a. The economic analysis results showed that the cost of harvesting work could be reduced by 12.7% compared to manual harvesting.

• 한국강구조학회 논문집
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• 제12권6호
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• pp.759-767
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• 2000

본 연구는 화재발생후에 시간경과에 따른 콘크리트충전 강관기둥의 내력변화를 파악하고 인장강도시험을 통해 내화실험이전과 후의 항복강도, 인장강도, 평균연신율 및 탄성계수 등에 대하여 각 단계별 하중에 따른 변형률을 비교측정하였다. 화재를 입은 강관내의 충전콘크리트의 물성변화(압축강도 및 탄성계수시험)를 파악하기 위하여 화재실험후 강관중심부에서 코아시험체를 채취하여 압축강도를 측정하고 탄성계수의 측정은 응력에 의한 변형률을 측정하였으며, 대상실험체의 화재온도를 추정하기 위하여 시차열분석을 실시하였다. 이러한 실험결과로부터 얻어진 자료를 평가하여, 향후 콘크리트 충전강관의 내화설계 구조규준제정에 필요한 기초자료를 제시하는데 그 목적이 있다.

• 한국식품조리과학회지
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• 제25권1호
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• pp.62-73
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• 2009

This study was conducted to evaluate the performance of sanitation management within school foodservice facilities and utilities in Gyeongbuk province. Data collection was carried out through surveys given to 200 school dietitians from the province. A total of 108 were usable, resulting in a 54.0% response rate. Statistical analyses were done using the SAS package program (version 8.2 for Windows). Of the study population, 58.3% had more than 10 years of work experience, and 64.8% worked in elementary schools. With regard to the style of foodservice system, 47.2% were urban and 46.3% were rural. Also, 89.8% of the school foodservices provided meals once a day. The performance of the sanitation management items of the facilities and utilities used to provide school foodservice was evaluated using a 5-point Likert scale. The average score for the 25 items was 3.35 points. 'HVAC system installed in foodservice establishment' had the lowest average score at 2.20 points. Whereas 'provide adequate storage capacity to allow refrigerating and freezing and an adequate thermometer is installed and temperatures monitored' had the highest average score at 4.19 points. Nine out of the 25 items were lower than the average score. The performance scores of high schools were significantly higher than those of elementary schools or middle schools for 'window materials are provided that are not liable to break' (p<0.001). The performance scores for urban style foodservices were significantly lower than for rural foodservices for 'floor of kitchen is constructed to maintain a dry system' (p<0.05). In response to questions on kitchen utensils and equipment, significant differences were shown according to the number of meals served per day in 21 out of 56 items, and the style of foodservice system showed significant differences in 14 of the 56 items. Foremost, to make better use of the foodservice facilities and utilities in Gyeongbuk province, immediate improvements should be made for management items in which the degree of performance was below the average score.

• 한국환경보건학회지
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• 제35권6호
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• pp.500-509
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• 2009

Passive samplers have been used for many years for the sampling of organic vapors in work environment atmospheres. Currently, all passive samplers used in domestic occupational monitoring are foreign products. This study was performed to evaluate variable parameters for the development of passive organic samplers, which include the geometry of the device and diffusive length for the sampler design. Four prototype diffusive lengths; A-1(4.5 mm), A-2(7.0 mm), A-3(9.5 mm), A-4(12.0 mm) were tested for adsorption performances to a chemical mixture (benzene, toluene, trichloroethylene, and n-hexane) according to the US-OSHA's evaluation protocol. A dynamic vapor exposure chamber developed and verified by related research was used for this study. The results of study are as follows. The results in terms of sampling rate and recommended sampling time test indicate that the most suitable model was A-3 (9.5 mm diffusive lengths on both sides) for passive sampler design in time weighted average (TWA) assessment. Sampling rates of this A-3 model were 45.8, 41.5, 41.4, and 40.3 ml/min for benzene, toluene, trichloroethylene, and n-hexane, respectively. The A-3 models were tested on reverse diffusion and conditions of low humidity air (35% RH) and low concentrations (0.2 times of TLV). These conditions had no affect on the diffusion capacity of samplers. In conclusion, the most suitable design parameters of passive sampler are: 1) Geometry and structure - 25 mm diameter and 490 $mm^2$ cross sectional area of diffusion face with cylindrical form of two-sided opposite diffusion direction; 2) Diffusive length - 9.5 mm in both faces; 3) Amount of adsorbent - 300 mg of coconut shell charcoal; 4) Wind screen - using nylon net filters (11 ${\mu}m$ pore size).