• 한국소음진동공학회논문집
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• 제21권7호
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• pp.637-642
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• 2011

The DMT freight is judged that economic performance is good because can increase cargoes than existing freight. However, the existing freight cars, each with a different balance to the body structure is bogie because the vibrations may occur. Thus, by minimizing vibration over the existing freight securing the safety of the driving if you will not have major problems in cargoes. In this study, multi-body dynamic analysis tool, VI-Rail using the actually Gyeongbu Railroad line and an empty, full freight condition include curve radius, track irregularity, The DMT freight of the derailed wagons were assessed for safety analysis. Full and empty freight conditions for parity in the Gyeongbu Railroad line(Dongdaegoo${\leftrightarrow}$Kyungsan) derailment safety analysis, such as derailment coefficient and the wheel unloaded, echoing the curve and the orbit is affected by the irregularity was found. Full freight condition than the empty conditions showed a significant derailment safety. Overall, the limits of derailment coefficient(Q/P = 0.8) and wheel unload decrement limits(${\triangle}P/P$ = 0.6) is less safe with me confirmed that the derailment safety.

• 한국소음진동공학회논문집
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• 제20권7호
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• pp.629-636
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• 2010

A Mobile Harbor is a new transportation platform which can load and unload has containers to and from very large container ships on the sea. Currently designed Mobile Harbor a catamaran type which is equipped with precisely controlled gantry crane on the deck, and can transport 250 TEUs at a time. Loading and unloading works by crane require very small motion of Mobile Harbor in waves, because it may be operated outside of harbors. In this project, applicability of both tuned-type anti-rolling tank and maglev-type active mass driver is studied as anti-rolling systems.

• 한국기계가공학회지
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• 제18권5호
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• pp.66-73
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• 2019

In this paper, we design a new automatic workpiece loading system for the loading and unloading of a workpiece for a CNC lathe. Conventional workpiece loading systems are bulky and require a large area when installed around a shelf. Therefore, an automatic loading system with small horizontal and vertical dimensions and a large loading capacity was designed. Structural analysis of the system was then carried out to assess the displacement and safety of the main components. Following this, the automatic loading system was manufactured according to the structural analysis results and conceptual design, and experiments characterizing the performance of the system were conducted. As a result, the automatic loading system was found to operate accurately and safely, meaning it can be used to load and unload workpieces for a CNC lathe.

• Geomechanics and Engineering
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• 제32권1호
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• pp.97-110
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• 2023

The coefficient of lateral earth pressure at rest in loose sand during virgin loading, K₀ , and during unloading, K'₀ , have been determined from laterally confined load-unload tests. The tests included measurement of lateral pressure with null pressure gauges, side wall friction with newly designed friction meters and applied pressure and base pressure with load cells. The importance of accounting for side-wall friction when evaluating the distribution of vertical pressure over the height of the soil specimen was demonstrated. Relatively uniform friction was observed during loading, but this was not the case during unloading unless friction reduction measures were employed. While the measured value of K₀ was found to be close to, if slightly higher than the value commonly estimated on the basis of friction angle, φ', the ratio of K'₀ to K₀ was found to reasonably fit an expression of the form K'₀/K₀ = 1 + C·log(OCR), with C equal to 1 in the present tests.

• 한국지능시스템학회논문지
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• 제23권3호
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• pp.202-207
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• 2013

본 논문은 물류 창고 내에서 화물이송을 위한 무인이송로봇을 설계 제작하고 운영기법을 제안한다. 무인이송로봇의 자율 주행을 위해서는 먼저 실시간으로 자기위치를 파악하고 목표지점까지의 경로를 추종해야 한다. 기존의 여러 방식이 제안되었지만 설치 및 유지보수에 대한 비용이 많이 들기 때문에 목적에 따라 유동적으로 작업 환경을 바꾸기는 어렵다는 단점이 있다. 무인 화물이송로봇의 리프트는 상하 운동을 통하여 수화물이 적재된 팔레트의 승하차가 가능하며, 구동 중 다양한 환경에서 여러 기능을 수행하기 위해 초음파센서, LRF센서, RFID, QR코드, 카메라를 장착하였으며, 목표지점까지 효과적으로 주행하며 화물운송을 하는 운영방법을 제안하였다. 제안한 주행 및 운영기법은 실험을 통하여 검증하였다.

• 재활간호학회지
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• 제5권1호
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• pp.27-37
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• 2002

During acute stages of hospitalized stroke patients, family caregivers face many challenges. They often experience emotional distress, social isolation, and financial constraints. However, the burden of caregiving of stroke patients in acute stages has never been studied properly. The purpose of this study was to investigate the factors related to the caregivers' burden with acute stroke. The subjects were 123 acute stroke patients and their caregivers who were admitted to neurology and neurosurgery units at Dan Kook University Hospital in Chung-Nam area. An interview was performed with the use of standardized questionnaire which included data pertaining to the patients/caregivers characteristics, caregiver burden (Modified Zarit's Burden Scale), and social support (Personal Resource Questionnaire). Our results showed that the mean burden score was 3.11, indicating high level of burden. Among the sub-domain scores, financial burden was the highest. In univariate analysis, the factors related to caregiver burdens were: inability to communicate between patients and caregiver(p<.001); low cognitive function of the patients(p<.001); low level of ADL(p<.001); the gender of caregiver(p<.001); the current employment status of caregivers(p<.01); the presence of social support for caregiver(p<.001); and the availability of alternative caregivers(p<.001). In multiple regression analysis, social support for family caregivers (87%), low level of patient's cognition (2%), availability of 2nd caregiver (1%), and gender of caregiver (female, 0.4%) were significant explanatory factors of overall burden. The caregivers' burden in acute stages during hospitalization following stroke was high. Recognition of high levels of caregivers' burden and those relating factors affecting caregiver burden may allow us to develop different nursing strategies to unload the level of burden for caregivers in acute stages of stroke.

• Composites Research
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• 제14권6호
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• pp.16-23
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• 2001

인발 와인딩에 의한 섬유강화 복합재료 중공 봉의 기계적 거동해석을 수행하였다. 이 목적의 수행을 위해 새롭게 제작된 와인더를 전통적 인발 시스템에 부탁하여 시편을 제작하였다. 또한 인발-와인딩된 시편을 제작할 수 있는 새로운 공법을 개발하였다. 이 연구를 위해 유한요소 해석 프로그램 POSTII를 확장 개발하였다. 비선형유한요소 수식화에는 2차 피올라-키르히호프 응력 텐서와 그린 변형률 텐서에 기초한 업데이트된 라그란지언 표현법이 사용되었다. 복합재료 중공봉의 유한요소 모델링을 위해 8절점 응축쉘요소를 사용하였다. 파손평가를 위해 모든 유한요소의 각 단층에서의 평균응력을 최대음력 판정법에 대입하였다. 수치해석 예로서 불포화 섬유강화 복합재료 중공 봉의 기계적 거동을 초기 하중상태에서 최종 붕괴가지 조사하였다. 파손에 따른 강성저하와 응력제하를 고려한 유한요소해석 결과는 극만 하중과 파손 및 변형에서 실험치와 잘 일치하였다.

• 인터넷정보학회논문지
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• 제6권5호
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• pp.11-25
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• 2005

최근 PDA나 핸드폰과 같이 제한된 계산능력을 갖는 이동 장치가 증가함에 따라 공개키 암호화 연산을 적용하는 모바일 IPv6 바인딩 갱신 인증 프로토콜에서 모바일 노드의 공개키 연산을 최소화하는 것이 강력히 요구되고 있다. 이를 위해 CAM-DH와 SUCV 같은 기존의 공개키 기반 프로토콜에서는 모바일 노드의 공개키 연산을 흠 에이전트에 위임하는 연산 최적화 옵션을 제공하였다. 그러나 이러한 프로토콜들은 연산 최적화 옵션을 제공하는데 있어서 여러 가지 문제점을 노출하였다. 특히, CAM-DH의 경우 홈 에이전트가 서비스 거부 공격에 취약하며 모바일 노드의 공개키 연산을 완전히 위임받지 못하는 문제점을 갖는다. 본 논문에서는 이러한 CAM-DH의 문제점을 개선하며 또한 Aura의 이중 해쉬 기법을 통해 CAM-DH에서 적용하는 CGA의 보안성을 강화시킨다. CAM-DH와의 비교를 통해 개선된 프로토콜이 모바일 노드의 계산 비용을 최소화하고 강화된 보안성과 향상된 관리능력을 제공함을 알 수 있다.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.413-422
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• 1993

Air shipment affords the quickest possible delivery of horticultural products. The price of air shipped horticultural products are relatively high as most of these products are perishable. Usually the temperature in the cargo compartment is not controlled during flight. Thus, special attention should be paid to procooling prior to shipment. The environmental condition during transportation of horticultural products is an essential parameter for maintaining the quality of perishable products. Commonly horticultural products were loaded by ULD(Unit Load Devices) as a container or pallet in the aircraft (except for small aircraft) . Therefore, inside temperature of the container and cargo compartment came into question. Scarce literature on the relationship between environmental condition and quality changes of horticultural products during air shipment can be found. By the stand point of keeping fresh quality, investigations on the actual condition of air shipments were carried out to improve the technique during the distribution process of fresh horticultural products. Temperature, humidity, atmospheric pressure, carbon dioxide, ethylene, impacts, and changes in quality during the air shipment of snapbeans, okras and chrysanthemums were measured. Temperature was measured by recording thermometers, relative humidity by recording hygrometers, atmospheric pressure by a strain -guage type pressure sensor, carbon dioxide by testing tubes, ethylene by sampling bags and a gaschromatograph, impacts and vibrations by impact recorders and a 3D accelerometer. Relationships between environmental conditions and quality changes during air shipments were clarified. It was expected from investigations into actual shipments that the ventilation and insulation properties of air freight containers were related to the quality of agricultural products. Aircraft can no directly load and unload trucks into them. The transshipment is inclined to cause shocks and vibrations, and to invite damages within a short time.

• 한국항해항만학회지
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• 제29권6호
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• pp.547-553
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• 2005

본 연구에서는 수직배치형 장치장 블록형태의 자동화 컨테이너 터미널을 대상으로 안벽에서 컨테이너의 양${\cdot}$적하 작업을 수행하는 안벽크레인(Q/C)에 대한 하역생산성을 평가해 보았다. 분석 대상이 되는 안벽크레인의 유형으로 기존의 싱글트롤리 타입외에 차세대 안벽크레인으로 인식되고 있는 듀얼트롤리 더블트롤리, 수직순환식의 하역방식을 가지는 네 가지 장비이다. 이들은 각기 다른 방식으로 선박의 컨테이너를 하역하며, 이들 각각에 대해 기계적 생산성과 순작업 생산성을 산출해 보았다. 특히, 안벽크레인의 순작업 생산성을 산출하기 위해 각 장비에 대한 시뮬레이션 모델을 수립하고 이를 적용한 시뮬레이션 시스템을 개발하였으며, 개발된 시뮬레이션 시스템을 통해 내 가지 안벽크레인에 대한 다양한 시뮬레이션이 수행되었다.