• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2013년도 추계학술발표대회
• /
• pp.301-302
• /
• 2013

LTE is the outstanding technology to transfer the data and voice. LTE consists of several nodes to transfer data. In case of the failure in the node of LTE, it could not support the service. So telecommunication-providers set up the back-up system for the simultaneous service-provision. But there is still the problem it comes to the network. Even though there is a back-up system, it would be useless the network is down. We propose the scheme to support the service in the case of this network problem in the LTE network. This scheme reduces 23% load in the LTE network in the case of the HSS node's failure or the network to the HSS nodes.

• 한국전기전자재료학회논문지
• /
• 제31권1호
• /
• pp.24-28
• /
• 2018

Insulators used in overhead transmission lines are continuously exposed to a number of mechanical and electrical stresses owing to external environmental factors, resulting in corrosion, reduction in durability, and deterioration. Widely used porcelain insulators are fabricated with cement and porcelain and are especially common in Korea. Changes in the hardness and chemical reactivity of the cement increase the leakage and fault currents and increase the possibility of flashover due to insulation breakdown. Therefore, it is important to evaluate the durability and defects of porcelain insulators. Studies on the reliability of various evaluation methods are needed to prevent accidents by accurately determining the replacement timing and potential defects in porcelain insulators. In this study, the hardness of the cement part of the porcelain insulator was measured using the Vickers hardness test and its composition was analyzed by energy dispersive spectroscopy and X-ray diffraction analysis. The performance of the insulators was compared in two different regions with varying climatic conditions. This study presents an evaluation method of the defects in porcelain insulators by measuring humidity, which can also be used to assess the reliability of the insulators.

• 농업과학연구
• /
• 제37권1호
• /
• pp.13-18
• /
• 2010

In order to prepare the technical fundamental in production of premium quality fruits of 'Niitaka' pears, we compared the quality parameters and storability of the fruits that had various fruit set position in a cluster. The fruits set on $4^{th}$ from basal part in fruit cluster had the largest fruit size. The weight of fruits set on the higher position than $4^{th}$ from basal part in fruit cluster showed decreasing tendency. The production rates of marketable fruits which had 500g to 899g in weight were the high in $3-5^{th}$ from basal part in cluster than those in other position. The differences of fruit height and diameter which represent balanced fruit shape also showed less difference in the fruits set on $4-5^{th}$ from basal part in cluster than the fruits set closely on basal part in cluster. The fruits set on $3-4^{th}$ from basal part in cluster showed lower rate in incidence of core breakdown and pithiness disorder during 4 months of cold storage than those on the closer position to basal part in cluster.

• 원예과학기술지
• /
• 제19권1호
• /
• pp.48-53
• /
• 2001

본 연구는 신품종 '감천'과 '추황' 배 과실에 있어 수확시기에 따른 저장성을 조사하여 이들 품종의 수확 후 관리를 위한 기초 자료로 활용하고자 하였다. '감천'은 대과로서 당도는 13.2% 이상으로 수확시기에 관계없이 높았고 산도는 0.082% 이하로 낮아 전반적인 품질이 우수하였고 저장 중 과피 흑변이 전혀 발생하지 않았지만 과심 갈변이 10월 중순 이후 수확한 과실에서 40% 정도로 높게 발생하였다. '추황'은 경도가 높고 산함량이 높으며 저장 중 과피 흑변이 수확시기에 관계없이 80% 이상 높게 발생하였고 과육갈변도 조기 수확한 과실에서 심하게 발생하였다. 따라서 수확 후 생리적 장해를 회피할 수 있는 적절한 수확시기와 이들 장해를 방지할 수 있는 수확 후 관리 기술의 개발이 필요하다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제55권4호
• /
• pp.178-182
• /
• 2006

Five model coils of 6.6 kV motor were manufactured with several defects. These stator coils have artificial defects such as void of groundwall insulation, removal of semi-conductive coating and damage of strand insulation. Epoxy-mica coupler(80 pF) was connected to five model coil terminals. The voltage applied to the coils was 3.81 kV, 4.76 kV, 6.0 kV and 6.6 kV, respectively. Partial discharge(PD) tests performed in the laboratory and shield room. Digital PD detector(PDD) and turbine generator analyzer(TGA) were used to measure PD activity. TGA summarizes each plot with two quantities such as the normalized quantity number(NQN) and the peak PD magnitude(Qm). The PD levels in pC were measured with PDD. PD patterns of model coils were indicated the internal and slot discharges. PD patterns are consistent with the result of measurement using PDD and TGA instruments. AC breakdown test was performed on five model coils in order to confirm the result of PD measurements. All the failures were located in a line-end coil at the exit from the core slot.

• 한국안전학회지
• /
• 제29권3호
• /
• pp.20-27
• /
• 2014

Cooling equipment is the frequent occurrence of fire despite the absence of the heating element. National fire statistics in 2013 show that a total of 263 fires occurred in the cooling equipment and the number of electric fan has 145 fire cases. This is accounted for 55.1% of the whole. Electric fan is the electrical appliance that the heat is generated on the winding wire and the iron core. If such characteristic is not controled properly, fire would break out at the electric fan. also there is a gap filled with an insulator between connection terminals of the capacitor in the electric fan. But in case that the gap on the capacitor is covered with some conductive material such as dust, there would be a fire as well caused by electrical heating locally. Although many studies related with those have been conducted, electric fan fire is continuously occurred. In this study, thermal characteristics and current signal in various conditions such as the heat generation of windings including iron cores of the motor and the dielectric breakdown of terminals on the capacitor connected to the motor were detected. In order to measure the maximum temperature, "third level" wind velocity button was pushed and the time selection switch to "continuation" was set. Analyzed data would be available for the fire safety of the electric fan.

• 한국해양환경ㆍ에너지학회지
• /
• 제16권1호
• /
• pp.17-24
• /
• 2013

해양레저 산업의 후발주자인 국내 해양레저 산업이 국내 시장 및 세계시장에 경쟁력을 가지기 위해서는 기획, 설계, 계획과 준비 등 제품 개발 및 제조의 각종 업무에 소요되는 시간과 비용을 단축시켜 높은 수준의 시장 적응력을 확보해야 한다. 위 사항들을 만족하기 위해서는 해양레저 산업 전반을 관리 할 수 있는 통합 시스템 구축이 절대 적으로 필요한 상황이다. 유관 산업 시스템간의 유기적 연결고리를 찾아서 요구되는 통합 정보를 확보하고 이를 단순 순차적 정보의 흐름이 아닌 통합적 정보 흐름과 객체 지향적 정보 분류체계를 확보하는 것이 주요 연구 핵심 사안이다. 이를 위하여 다른 유사 산업에서 실재 정보 체계를 활용한 사례 및 산업생산에 적용된 제품수명주기관리(PLM), 제품 데이터 관리(PDM), 가상 생산(DM)과 같은 방법론을 검토 하고 이를 구성 및 적용하여 실질적으로 활용되고 있는 정보 체계 및 작업분류체계(WBS)의 사례를 연구하여 비교 한다. 이를 통하여 해양레저산업을 위한 기본적인 작업분류체계 구성을 추진하며 실재 업체에서 현재 활용중인 정보를 입력, 대입을 통하여 실증적으로 검증하고 해양 레저 산업의 고유한 영역을 추가하여 해양레저 작업 분류 체계(MLWBS)를 완성한다. 본 해양레저 작업 분류 체계를 바탕으로 여러 가지 정보체계 및 제품, 설계, 엔지니어링, 생산, 구매, 영업, 마케팅, AS, 고객지원 등에 다양한 형태의 활용이 가능 하도록 할 수 있을 것이다.

• Nuclear Engineering and Technology
• /
• 제55권5호
• /
• pp.1604-1615
• /
• 2023

In an open-pool type research reactor with a downward forced flow in the core, pipes can be under sub-atmospheric pressure because of the large pressure drop at the reactor core in the atmospheric pool. Sub-atmospheric pressure can result in air inflow into the pipe from the pressure difference between the atmosphere and the inside of the pipe, which in a postulated pipe break scenario can lead to the breakdown of the cooling pump. In this study, a plant-scale experiment was conducted to study air inflow in large piping systems by considering the actual operational conditions of an advanced research reactor. The air inflow rate was measured, and the entrained air was visualized to investigate the behavior of air inflow and flow regime depending on the pipe break size. In addition, the developed drift-flux model for a large vertical pipe with a diameter of 600 mm was compared with other correlations. The flow regime transition in a large vertical pipe under downward flow was also studied using the newly developed drift-flux model. Consequently, the characteristics of two-phase flow in a large vertical pipe were found to differ from those in small vertical pipes where liquid recirculation was not dominant.

• 지역연구
• /
• 제11권1호
• /
• pp.79-91
• /
• 1995

As an exit to solve the economic depression of the development countries in the early twentieth century, the 'old international division of labor' developed. The economic crisis(i.e., under-consumption crisis) was due to the absence of the mode of regulation compatible with the extensive regime of accumulation(i.e., "Fordist" regime). The crisis was solved by the state intervention through the creation on institutions in order to increase the level of consumption. Until the late 1960s when "high Fordism" reached(i.e., a harmonious relation between the monopoly mode of regulation and the intensive accumulation of capital), the developed core countries enjoyed a remarkable economic growth. The external market was not a necessity for the economic growth because there were increases in labor productivity and proportional increases in real wages and thus increases in consumption level. In the 1970s, however, the core faced with economic crisis again. Due to the breakdown of the postwar "Fordist" regime of capital accumulation and the post 1973 world depression, the core needed the Third World as a solution for their internal and international economic crisis. Thus the 'new international division of labor'(NIDL) arose. The "Fordist" method of production(i.e., the divisions of production process) led to the territorial division of labor and to the detailed division of labor. The aim of the NIDL is to exploit reserve armies of labor on a world scale and thus to reduce production costs. According to the NIDL model, the Third World countries have been developing by the core countries' investment on mainly labor-intensive industries and thus have been playing an important role in the global economy. And the NIDL theorists argue that multinational corporations have increasingly invested in the Third World nations and contributed to the economic growth in those regions. Tables presented in the paper show that the global trend since the 1970s does not follow the argument exactly as the NIDL theorists predicted. On the contrary, the core countries focus on developing technology, adopting the automation of production process, and trading within the core countries rather than on investing in the periopheral countries. The continuing investment of multinational corporations into the periphery is not because of cheap labor force but because of the market potentials in the regions. Majority of corporations of the core tries to reduce production costs by investing in technological development more intensively and also by changing regional strategies (i.E., investment from metropolitan areas to medium - or small - size cities, focusing on agglomeration economy, boosting regional diversification, etc.) within their own countries. The main purpose of the paper is to review and to criticize the NIDL theory based on some empirical data.IDL theory based on some empirical data.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• 제3권3호
• /
• pp.177-188
• /
• 1999

The effect of ABA on the chloroplast disassembly of Zea mays was investigated by measuring the changes in the relative distribution of chlorophyll(Chl) between the Chl-protein complexes in ABA treated and untreated sensecting leaves. The reaction center(RC)-light harvesting complex(LHC) regions were rapidly disassembled in the late stage of dark-induced senescence. Plus, during dark-induced senescence, the disassembly of a reaction center of P700 apoproteins containing mainly Chl a was faster than that of a reaction center of LHCI apoproteins containing both Chl a and Chl b. The increase in the relative distribution of Chl-protein complexes in the RC-Core2 in the late stage of senescence was due to the accumulation of core complexes such as CP47/43 and reaction centers including D1/D2 apoproteins disassembled from the RC-Corel containing the dimer of D1/D2 apoproteins. The LHCII region was more stable than the other Chl-protein complexes throughout leaf senscence. Accordingly, it is suggested that the preferential breakdown of Chl a gives rise to the disassembly of Chl a-binding proteins, particularly reaction centers and core complexes during dark-induced senescence, plus the primary target of the photosynthetic apparatus in sensecing leaves would seem to be Chl a along with the proteins associated with Chl a. The application of ABA promoted the disassembly of the P700 apoproteins in the PSI reaction center and the dimer of D1/D2 apoproteins, and the conversion of the trimeric LHCII apoprotein to the monometirc LHCII apoprotein during the middle stage of leaf senescence, thereby suggesting that ABA accelerates the disassembly of both Chl a-binding and Chl a+b-binding proteins, particularly Chl a-binding proteins during the middle stage of leaf senescence.