• 한국안전학회지
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• 제32권2호
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• pp.46-51
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• 2017

This paper presents classification of domestic fire detector using response time index. Response time is measured using fire detector distributed in Korea, and the response time index is estimated. Plunge test prescribed by FM is conducted to measure response time of fire detector. The detector used to test is fixed temperature type(thermistor and bimetal type) and rate of rise temperature type(thermistor and pneumatic type). The nominal operation temperature of fixed temperature type detector is $70^{\circ}C$ and rate of rise temperature is $15^{\circ}C/min$. The fixed temperature type is measured 7 products, and the rate of rise temperature type is measured 5 products. The results show that in case of fixed temperature type(thermistor) is classified "Quick" or "Standard" and fixed temperature type(bimetal) is not classified. The rate of rise temperature type(thermistor) is classified "Fast" or "Ultra Fast" and the rate of rise temperature type(pneumatic) is classified "Very Fast" or "Ultra Fast". The pneumatic type shows more fast response than thermistor type. Also these results indicate the fixed temperature type(bimetal) is not suitable for early stage fire detection.

• 수산경영론집
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• 제27권2호
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• pp.65-82
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• 1996

This study aims to investigate the development of the stow-net fishery operated in East China Sea and Yellow Sea and its role in the off-shore demersal fishery In Korea after 1980's. This paper also reorganization problems of this fishery under 200 mile exclusive economic zen system. Stow-net fishery which has an important role in offshore demersal fishery in terms of the fish production and supplies had attained an rapid growth since 1960's throughout advancement of the fishing technique, government support and enlargement of fish market. However, the production had come to a stagnant stage since 1980, and even reduced in 1990's by reason of competition from Chinese vessels which have been developing reapidly as well as other more productive demersal fishery such as trawl of Korea. Nevertheless, high fish price has maintained the business of this fishery. This fishery faces some difficulties such as limited resources, the plunge of fish price due to fish import freedom, and 200 mile EEZ settlement in those Seas among the related countries ratifying the United Nations Convention of the Law of the Sea in 1996. This paper discusses the reorganization problems of the stow-net fishery under the new situation. : (1)to lighten a damage to the fishery to keep the fishing ground and to restrict the entry of competitive fisheries, (2)to reduce the fishing effort by the governmental support, (3)to introduce new fishing methods, (4)to employ foreigner as a cheep labour, (5)to rise fish price throughout more freshness of fishes.

• 수산경영론집
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• 제51권1호
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• pp.53-66
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• 2020

The Ministry of Maritime Affairs and Fisheries is supporting the "Environmentally Friendly Fisheries Promotion and Private Assistance Project" to increase production of eco-friendly, high-value-added foods. Private-backed operators selected for the project will have an economic opportunity to build, expand or refurbish eco-friendly fishing grounds. To facilitate this, the scope of project support was expanded after 2015 and an opportunity was prepared for private subsidy projects to grow to a new level in terms of quality and quantity by switching to a public offering project. However, starting in 2017, demand from the private sector will plunge and selected projects will be delayed or the project implementation rate will be lowered. It was a time for subsidy-related laws and systems to be reinforced but private subsidy projects do not temporarily shrink simply due to the increased administrative burden on private subsidy operators on subsidy management. It plans to review the correlation between laws and systems related to the construction of fish farms and suggest ways to enhance the efficiency of implementation so that economic advantages, the biggest advantage of the private subsidy project, can be recovered within the current legal system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.284-287
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• 1987

In this paper, the design and implementation of a multiprocessor based Die Bonder Machine for the semiconductor will be described. This the partial research result, that is, the 1st year portion of the project to be performed for a period of two years from June, 1986 to May, 1988. The mechanical system consists of the following three subsystems : (i) transfer head unit, (ii) die feeding XY-table unit, and (iii) plunge up unit. The overall control system is designed to be essentially a master-slave type in which each slave is functionally fixed in view of software and also the time shared common bus structure with hardwired bus arbitration scheme is utilized, the control system consists of the following three subsystems each of which employs a 16 bits microprocessor MC 68000 : (i) die bonder processor controller, (ii) visual recognition/inspection and display system, (iii) the servo control system. It is reported that the proposed control system were applied to Working Sample and tested in real system, and the results are successful as a working sample phase.

• 한국유기농업학회지
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• 제18권2호
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• pp.135-154
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• 2010

The green craze has hit all the world lately. The green revolution which means immense changes for sustainable development under the new environment-economy system is foretelling that we should have new angle to the environment and economy. This paper is about the development of the model and indicators for construction of ECO(Energy Circulating Organic)-Village which is the green growth option of local community. This model is composed of three concepts - SPDC (about procedural methodology of Model), Virtuous Circle (about functional relationships of three requisites), Network (about spatial relationships between communities) - and evaluation indicators. Environment, tourism, industry (Energy & Organic Agriculture) are set as the three requisites for green growth of local community. Nations of the world plunge into the green war which is silent, general, sweeping changes. We can not win this war with the existing thinking system and policy. We need revolutionary changes reconsidering of environmental value and sustainable development strategy of the region. Each of us should go through the changes and this work would be the one among those efforts.

• 한국산림과학회지
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• 제95권5호
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• pp.585-590
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• 2006

In vitro-grown axillary shot-tip meristems of Lycium chinense Mill. from cold-acclimated plant were successfully cryopreserved using a vitrification technique. After loading for 15 minutes with a mixture of 2.0 M glycerol and 0.4 M sucrose ($20^{\circ}C$), small segments (1-2 mm, 3-4 mm, and 5-6 mm) were cut from axilary buds and exposed to the cryoprotectant solution containing 30% glycerol, 15% ethylen glycol,15% dimethyl sulfoxide (DMSO), and 0.4 M sucrose at $0^{\circ}C$ for 30-120 minutes prior to direct plunge into liquid nitrogen (LN). After rapid thawing ($40^{\circ}C$), the segments were washed with MS medium containing 1.2 M sucrose for 0-35 minutes, and then transferred onto recovery-growth medium. The highest survival rate (about 90%) was obtained with cold-hardening treatment, and cryopreserved explants were successfully recovered to plantlets. No abnormal morphological changes were observed with the recovered plants after cryopreservation.

• 한국지형학회지
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• 제24권3호
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• pp.47-59
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• 2017

This study aims to analyze geomorphologically Jaein Falls in Hantangang Lava Plateau for the landform structure, landform classification, falls dissection and recession. The height and recession length of the Falls are approximately 18m and 340m. after dissection valley arrive at area of the Jijangbong Volcanic Rock Complex of Mesozoic era, the fall will disappear. The structure of the dissection valley shows totally well vertical columnar joint near falls and plunge pool, colluvial talus deposits toward lower reach by the freezing-thawing and wet-dry activities, and alluvial cone and delta in estuary to Hantangang River. The Falls' age date and recession rate in the valley maybe relate to the age of the lava plateau. The estimated recession rate of the fall should be 8.75m/ka to 2.3m/ka, depending on the age 500ka to 40ka in lava plateau.

• Ecology and Resilient Infrastructure
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• 제7권4호
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• pp.320-326
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• 2020

본 연구는 횡단구조물에서의 어류의 이동 특성에 따른 종적 연결성을 평가하였다. 대상 구간은 원주천이며, 대상 어종은 피라미와 잡고기를 대상으로 하였다. 흐름 분석은 HEC-RAS 모형을 사용하였으며, 종적 연결성 분석은 ICE 방법을 적용하였다. 종적 연결성을 분석하기 위하여 수리분석 결과물 중 횡단구조물 상·하류 수위차, 유속, 하류단 웅덩이 깊이에 따른 대상 어종의 유영 속도를 적용하였다. 그 결과 피라미의 경우 종적 연결성이 약 76점, 잡고기의 경우 종적 연결성이 약 23점으로 나타났다.

• 한국정밀공학회지
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• 제14권5호
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• pp.85-91
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• 1997

Air grinding time in grinding process has a great effect on its efficiency due to low feedrate. This paper presents a reduction methos of air grinding time in cylindrical plunge grinding operation. Tje reduction of air grinding time is accomplished by finding the distance between contact point and rising point of ultra- sonic signal of the grinding wheel to workpiece. It uses a variation of sound signal generated by the flow of coolant when the grinding wheel approaches to workpiece. The ultrasonic sensor with 23 kHz center fre- quency and 8 kHz bandwidth is used to find the nearest approaching point(NAP). Monitoring and control system of the grinding conditions is implemented with CNC controller to control feedrate override and ultrasonic sensor to find NAP. The experimental result shows that the ultrasonic signal is a good measure- ment to find NAP. But it needs the considerations for the effect of the relationship between flowrate of coolant and diameter of workpiece.

• 한국분말재료학회지
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• 제31권1호
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• pp.37-42
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• 2024

Friction stir spot welding (FSSW) is a solid-state joining process and a rapidly growing dissimilar material welding technology for joining metallic alloys in the automotive industry. Welding tool shape and process conditions must be appropriately controlled to obtain high bonding characteristics. In this study, FSSW is performed on dissimilar materials AA5052-H32 aluminum alloy sheet and SPRC440 steel sheet, and the influence of the shape of joining tool and tool insertion depth during joining is investigated. A new intermetallic compound is produced at the aluminum and steel sheets joint. When the insertion depth of the tool is insufficient, the intermetallic compound between the two sheets did not form uniformly. As the insertion depth increased, the intermetallic compound layer become uniform and continuous. The joint specimen shows higher values of tensile shear load as the diameter and insertion depth of the tool increase. This shows that the uniform formation of the intermetallic compound strengthens the bonding force between the joining specimens and increases the tensile shear load.