• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제32회 추계학술대회 정기총회
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• pp.266-272
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• 2000

The importance of variable displacement piston pump is recently increasing in industrial applications, as it is widely used for raising the energy level of the fluid in hydraulic system. The regulator is the device that controls the pump output flow depending on the machine load and engine speed, and that regulates the discharge flow of the piston pump by controlling the swivel angel. This work deals with constant power control of a regulator system in bent-axis type piston pump. In order to use engine power effectively, it is important to keep the horsepower from the engine to the pump constant. Therefore, optimum power usage is obtained by accurately following the power hyperbola. First, the governing equations of the regulator are derived, and analysis is performed by numerical simulation in which significant parameters of regulator are identified. Also, we designed and manufactured the prototype of the constant power control regulator for experiments. The experimental results show the responsibility and pressure-flowrate characteristics and these are compared with the theoretical analysis. As the result, it is confirmed that the characteristics of the designed regulator correspond to the numerical simulation.

• 한국항공운항학회지
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• 제26권4호
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• pp.116-121
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• 2018

According to the incresement of aging aircraft, Republic of Korea Air Force (RoKAF) conducted a teardown inspection of aircraft's EWIS (electrical wiring interconnection system) to determine the status of deterioration and the influence of failure occurrences due to it. The inspected aircraft were the retired fighter jets that had been used for more than 40 years. By analyzing defect type and the defect tendency, RoKAF can establish the necessary measures for the usage extension of their fleet and furthermore, the analysis results can be used as a basic data for the preparation of it's aircraft aging. EWIS inspection was done throughout careful visual inspection technique by removing all the ducts and pipes located in the fuselage and wings. For the aircraft wiring where no damage was found, the elongation tests were performed to determine the deterioration of wiring according to the location of the aircraft. The connectors, which is the main cause of intermittent failure, were completely disassembled and inspected for internal damage such as corrosion, abrasion, and traces of foreign objects. The detected defects were classified into 4 severity levels based on the type of damage, and the classified defects were weighted according to the criticality which may affects to it's system to establish the action plan.

• 신재생에너지
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• 제16권4호
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• pp.41-48
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• 2020

This study performed a single hole operation method using a balancing well-cross-mixed underground heat exchanger, and conducted thermal performance studies of an SCW-type underground heat exchanger using a two-well. The study attempted to change the existing operating method of the two adjacent SCW underground heat exchangers with one ball each. The SCW-type geothermal heat exchanger is considered to enable up to 20% of bleed discharge at maximum load, which makes groundwater usage unequal. The efficiency factor of the geothermal system was improved by constructing the discharged water by cross-mixing two balancing wells to prevent the discharge of groundwater sources and keep the temperature of the underground heat exchanger constant. As a result of the cooling and heating operation with the existing SCW heat exchange system and the balancing well-cross-mixed heat exchange system, the measured performance coefficient improved by 23% and 12% in cooling and heating operations, respectively. In addition, when operating with a balanced cross-mixing heat exchange system, it has been confirmed that the initial basement temperature is constant with a standard deviation of 0.08 to 0.12℃.

• Nuclear Engineering and Technology
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• 제55권8호
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• pp.2734-2741
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• 2023

Brachytherapy is a special case of radiotherapy. It should be arranged according to some principles in medical radiation applications and radiation physics. The primary principle is to use as low as reasonably achievable dose in all ionizing radiation applications for diagnostic and therapeutic treatments. Dosimetric distributions are dependent on radioactive source properties and radiation-matter interactions in an absorber medium such as phantom or tissue. In this consideration, the geometrical structure and material of the seed capsule, which surrounds a radioactive material, are directly responsible for isodose profiles and dosimetric functions. In this study, the radiometric properties of capsule material were investigated on dose distribution in a water phantom by changing its nuclear properties using the EGSnrc Monte Carlo (MC) simulation code. Effective atomic numbers of hypothetic mixtures were calculated by using different elements with several fractions for capsule material. Model 6711 brachytherapy seed was modeled by EGSnrc/Dosrcnrc Code and dosimetric functions were calculated. As a result, dosimetric parameters of hypothetic sources have been acquired in large-scale atomic number. Dosimetric deviations between the data of hypothetic seeds and the original one were analyzed. Unit dose (Gy/Particle) distributions belonging to different types of material in seed capsule have remarkably differed from the original capsule's data. Capsule type is major variable to manage the expected dose profile and isodose distribution around a seed. This study shows us systematically varied scale of material type (cross section or effective atomic number dependent) offers selective material usage in production of seed capsules for the expected isodose profile of a specific source.

• 농업과학연구
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• 제48권4호
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• pp.987-1001
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• 2021

One of the most critical issues in the dairy industry, alongside the low birth rate and the aging population, is the decrease in demand for milk. In this study, the consumption trends of 12 major dairy products distributed in Korea were predicted using a logistic model, the Gompertz model, and the Bass diffusion model, which are representative S-shaped growth models. The 12 dairy products are fermented milk (liquid type, cream type), butter, milk powder (modified, whole, skim), liquid milk (market, flavored), condensed milk, cheese (natural, processed), and cream. As a result of the analysis, the growth potential of butter, condensed milk, natural cheese, processed cheese, and cream consumption among the 12 dairy products is relatively high, whereas the growth of the remaining dairy product consumption is expected to stagnate or decrease. However, butter and cream are by-products of the skim milk powder manufacturing process. Therefore, even if the consumption of butter and cream grows, it is difficult to increase the demand of domestic milk unless the production of skim milk powder produced from domestic milk is also increased. Therefore, in order to support the domestic dairy industry, policy support should be focused on increasing domestic milk usage for the production of condensed milk, natural cheese, and processed cheese.

• 디지털융복합연구
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• 제20권4호
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• pp.159-168
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• 2022

본 연구는 외식동기요인을 기초로 하여 세분집단을 분류한 다음 인구통계학적 특성과 이용행태별, 이용동기가 외식점 선택행동과의 미치는 영향관계를 분석하고자 2021년 7월 15일부터 8월 14일 한달간 설문조사를 실시하였고 총 310부를 실증분석에 사용하였다. 연구결과 첫째, 외식동기에 따른 세분집단간 인구통계학적 특성에 따라서 미치는 영향관계에서 업무형은 남성이 여성보다 높게 나타났고, 군집수가 많은 변화형, 식도락형, 적합형은 여성이 높게 나타났다. 둘째, 인구통계적특성에서 모든 집단들이 공통적으로 31-40세, 41-50세의 기혼자들이 외식동기가 강한 것으로 나타났다. 셋째, 외식동기에 따른 세분집단간 이용행태적 차이에서 가장 선호하는 메뉴는 변화형을 제외한 업무형, 식도락형, 적합형은 한식이 가장 높았고, 변화형은 양식이 가장 높았다. 넷째, 세분집단간 이용행태적 차이의 주문방식에서 4개의 집단이 모두 무한리필이나 뷔페식보다는 주문식이 높게 나타났다. 본 연구의 한계점으로는 분야를 한정하여 분석이 이루어 져야 하지만 특정음식종목에 대하여 연구결과를 얻지 못하였다. 따라서 향후 연구에서는 특정 음식분야를 지정하여 구제적인 연구가 이루어지길 바란다.

• 한국구조물진단유지관리공학회 논문집
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• 제13권1호통권53호
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• pp.195-204
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• 2009

강판부착공법은 철근콘크리트(RC) 보의 전단내력이 부족한 경우에 일반적으로 사용되는 보강공법 중의 하나이다. 그러나, 기존의 solid형 강판보강공법은 강성이 우수한 반면 취성적 부착파괴, 비효율적인 재료량 및 시공성 등의 문제가 알려져 있으며, 띠형 강판보강공법은 제한된 접착면적과 강판의 비일체적 거동 때문에 보강효과가 낮게 되는 단점이 있다. 따라서, 본 연구에서는 이러한 문제점을 개선할 수 있는 Slit형 강판을 사용하여 전단내력을 보강하는 방법을 제시하고 이 공법의 보강효과를 분석하고자 하였다. 전단경간 내에서 수직 Slit형 강판의 폭, 간격 및 두께를 주요 변수로 하는 13개의 시험체를 제작하였으며, 본 연구의 실험결과 및 기존 띠형 강판으로 전단보강된 RC 보의 실험결과를 비교 분석하고 Slit형 강판공법의 보강효과를 정량적으로 규명하였다. 실험결과, 기존의 개별적 띠형 전단보강방법에 비하여 일체화된 수직 Slit형 강판으로 보강한 경우에 더 높은 전단내력을 보였으며, 이는 강판과 RC 보의 일체성이 높아지고 강판의 부착면적이 증대되기 때문인 것으로 판단된다.

• 한국화재소방학회논문지
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• 제31권3호
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• pp.73-78
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• 2017

본 논문에서는 바이메탈식 온도센서를 적용한 건조설비에서의 화재 위험성에 대하여 연구하였다. 건조설비는 산업현장 등에서 광범위하게 사용되고 있으며, 건조 대상물이 가열될 때 발생하는 가연성 가스 및 증기에 의한 폭발 및 화재 등이 일어나기 용이하기 때문에 구조와 사용방법 등에 대한 규제가 엄격하게 이루어지고 있지만 부적합한 온도센서를 활용한 건조로 등의 내부온도 측정시 정확한 온도 측정이 이루어지지 못하는 경우에는 그만큼 화재 위험성이 증가하게 된다. 따라서 본 논문에서는 건조설비에 광범위하게 사용되고 있는 바이메탈식 온도센서의 구조를 분석하고, 측정 대상물의 성상에 따른 온도 측정 실험을 수행하였다. 측정 대상물에 따른 온도 측정 결과, 기체 및 고체에 대한 온도 측정에 있어서는 실제 온도에 비해 낮은 온도로 측정되었으며, 액체 대상물의 경우에는 비교적 정확한 온도 측정이 가능하였다. 이러한 실험 결과로부터 바이메탈식 온도센서는 기체 및 고체의 온도 측정에는 부적합하며, 액체의 온도 측정에 보다 적합한 특성을 나타내었다.

• 복식문화연구
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• 제5권4호
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• pp.112-129
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• 1997

This research, focused on the curved of the lower body, designated abdomen and hip gradient, crotch depth and crotch width the factors for which are able to influence on the appearence and the function of Divided Skirt and analized the changes when that were applied to a real pattern, and so the purpose of this research is to show the basic documents needed to design a Divided Skirt pattern fitting with the wear purpose and usage. The following are the results of this research. 1. The abdomen and hip gradient turned out as the most influential factor on the appearance and the function of Divided Skirt. The pattern of which the abdomen and hip gradient was designated as vertical zero degree, showed an excellent appearance and in case of function, the pattern of which thw angle of the abdomen and hip gradient of human body type was applied to itself without a particular designation turned out excellent. 2. In case of crotch depth, the pattern which had crotch depth＋2㎝, had a better appearance but influced nothing on function. 3. The factor of crotch width didn\`t have any influence on the appearance and function of Divided Skirt. 4. Referring to the results of the above, the Divided Skirt pattern of which the appearance and the function turned excellent, had the angle of abdomen gradient 4 degrees, the angle abdomen gradient 4 degrees, the angle of hip gradient/2+2.5 degrees, crotch depth+2㎝ and crotch width following human body type. In case of Divied Skirt worn when going out, the pattern which had the angle of abdomen and hip gradient vertical zero degree, crotch depth+2㎝ and crotch width following human body type, turned out suitable. Also, the suitable pattern of Divided Skirt for working had the abdomen and hip gradient following human body type, crotch depth+2㎝ and covering girth diameter/2±1㎝.

• 산경연구논집
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• 제11권7호
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• pp.41-49
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• 2020

Purpose: The purpose of this study is to recognize the role and necessity of public data visualization through prior research, investigation, and data verification processes. In addition, this study intends to check what factors should be considered in order to visualize data on the mobile web. Through this process, by identifying the cognitive load affecting information visualization by type, as a result, I would like to propose an effective information visualization method to effectively deliver public data related to government policies. Research design, data and methodology: In this study, we analyzed the case of information visualization according to infographics, which has been widely used in the public field among various visualization methods. For this study, a questionnaire survey was conducted for young people in their 20s and 30s with the highest mobile usage rate. Results: Based on the results, IPA (Importance Performance Analysis) was performed to conduct cognitive load test tools for information visualization of public data and confirmed the implications for each type of infographics. Conclusions: As a result of research, in order to efficiently deliver public data on the mobile web, first, it is necessary to construct a visual screen that can be easily identified through clear data. Appropriate graphic elements can be used according to the type to make it easier for users to acquire and understand information. Second, it is necessary to provide useful content in visualizing information. Third, in order to efficiently transmit information and increase understanding of data, it is necessary to visualize information that can induce interest in data and form metaphors. Fourth, it is necessary to visualize information to reduce cognitive load in terms of physical and mental aspects in order to accommodate users' comfortable information. Fifth, in order to effectively deliver public data, it is necessary to compose contents and information that are easy for users to understand. This study examines effective information visualization methods to increase the communication effect of public data in response to changes in the data-based intelligent information society and suggests implications for each type considering cognitive loads to help future public institutions to communicate and accept information.