• 한국항행학회논문지
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• 제24권3호
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• pp.173-183
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• 2020

본 연구는 인천국제공항(ICN)-두바이국제공항(DXB)의 정기 노선을 취항하고 있는 대한민국 국적항공사 및 중동 국적항공사를 이용객들을 연구의 대상으로 하였다. 항공시장의 자유화 압박 속에서 국적항공사 대(對) 외국항공사의 시장 경쟁이 가장 치열한 노선들 중 하나이기 때문이다. 실증연구를 통해 국적항공사의 경쟁적 우위는 무엇이고 향후 시장 자유화 확대 기조에서 치열한 경쟁에서 살아남기 위한 지속가능한 전략이 무엇인지 시사점을 도출하고자 하였다. 인천-두바이 노선에서 국적항공사 이용객들의 우수한 제품 편익에 대한 인식은 가격 프리미엄을 지불하고서라도 재구매 의도에 유의한 영향을 미치는 것으로 판명되었다. 반면 외국항공사 이용객들의 제품 편익은 저렴한 가격과 아무런 상관성이 없는 것으로 분석되었다. 국적 항공사의 제품 편익을 향후 더욱 강화한다면, 동 노선에서 외국 항공사들의 가격 우월성과 경쟁하고 시장에서 경쟁적 우위를 지속적으로 유지할 수 있을 것이다.

• 대한인간공학회지
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• 제31권2호
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• pp.379-388
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• 2012

Objective: This study developed a new shower carrier prototype to reduce caregivers' muscle burden and to increase use convenience by reflecting the needs of domestic long-term care institutions. Background: In the long-term care institutions, one of the ADL(Activities of Daily Life) factors is bathing/showering. Recently, bath/shower-assisting equipment is actively being introduced in care institutions to reduce the caregivers' care cost, but most of the domestic equipment was designed to imitate foreign products and rarely reflected the needs of care institutions. Method: Based on Korean elderly people's body information, the bed size(length: 1,900mm, width: 650mm) was set-up, and a variable headrest with a newly designed headform was developed to provide the comfort for the elderly and convenience for caregivers. To reduce caregivers' muscle burden on transferring and showering activities, a 3-step column lifting module equipped with dual actuators(lowest/highest levels from the ground: 600/1,100mm, Stroke: 500mm) was developed, and the wheelbase parameter(length: 1,250mm, width: 580mm) was defined securing the turn-over safety of the shower carrier. The drivability tests were performed for the prototype and foreign product, and the male and female subject's muscle activities were measured through the tests. Results: The structural stability of the shower carrier prototype was secured by finite element analysis, and the muscle activities of the subjects through the drivability tests largely decreased in the prototype, compared to the foreign product. Conclusion: In this study, a new shower carrier prototype was developed to possibly reduce caregivers' muscle burden and to increase use convenience based on the needs of long-term care institutions. It was expected that the drivability performance of the prototype could be relatively superior to that of the foreign product. Application: The results obtained from the study can be applied for the optimal development of a shower carrier including other equipment to effectively care for the elderly.

• 한국식품영양과학회지
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• 제26권1호
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• pp.81-86
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• 1997

대추를 이용한 가공제품의 하나로서 분무건조에 의한 분말음료의 개발을 시도하였다. 대추 추출액은 그 자체로는 모든 농도 범위에서 분무건조 하기가 불가능하였고 건조보조제의 첨가에 의해서 분말음료로의 제조가공이 가능하였다 대추 추출액은 26。Bx 농도까지 농축시키고 알맞은 건조보조제를 첨가하여 최종농도를 30。Bx로 조정하여 분무 건조시켰다 첨가되는 건조보조제의 양은 대추 추출액과 건조보조제의 비율이고 형물 기준으로 1:1정도까지 흔합했을때 건조가 용이하고 얻어지는 제품의 품질이 양호하였다. maltose, 농축유, gum arabic, dextrin등의 건조보조제를 검토한 결과 maltose와 gum arabic을 흔합하여 사용할 때 제품의 관능적 특성이 가장 우수하였다. 대추 추출시의 효소처리는 수율을 13~39% 향상시 킬 수 있었다. 그렇지만 효소처리가 분말대추음료의 관능적인 특성에 부정적인 영향을 나타내었으며 추출수율 향상을 위해 사용되어진다면 품질열화가 적은 pectinase의 0.5% 처리가 가장 바람직한 것으로 나타났다.

• 대한안전경영과학회지
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• 제17권2호
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• pp.161-175
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• 2015

This study analyzed that the infant carrier standard affects the satisfaction of certification. Baby Carrier Safety requirements in the Republic of Korea is enforceable by court duty certification. Therefore, a test was conducted to compare with the safety requirements of the United States and Europe and the survey was conducted to know how much manufacturers and importers are satisfied with the certification. According to the test result, there is a difference between domestic and foreign safety requirements about flame retardancy. As a result of the survey, The satisfaction of the certification is proportionate to the one of product standard.

• 대한조선학회논문집
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• 제46권3호
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• pp.279-289
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• 2009

For a Product Oil Carrier, longitudinal bulkhead as well as transverse one is corrugated shape in general and intersection part of bulkheads is utilized for a pipe trunk. Since lower and upper stools are to be connected with all of longitudinal and transverse bulkheads, they have a uniform height respectively. The purpose of this study is the development of design system for the minimization of total weight of longitudinal and transverse bulkheads at the initial design stage. In this study, the beam element models for longitudinal and transverse corrugated bulkheads are established and they are applied to the structural analysis. For the practical design, the selection and the position of an additional pipe trunk are considered in this study. In addition the required minimum distance between the bracket installed along the web of corrugation at lower stool and the diaphragm is taken into consideration during optimization process. Evolution strategy(ES) is adopted as an optimization technique.

• 대한조선학회논문집
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• 제53권6호
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• pp.456-464
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• 2016

To design the modified hull form with relatively unfavorable dimensions and constraints than the parent ship the stepwise design was applied. In each design step the resistance characteristics was estimated by numerical calculations using CFD programs as Wavis 1.4, Wavis 2.1 and Fluent 12.1. The wave profiles along hull surface by potential flow calculations were investigated to improve wave resistance by modifying the bow shapes. To improve the stern shapes with a point of viscous form resistance the pressure distributions on hull surface and the limiting streamlines are investigated by viscous flow calculations. The design objectives such as shortening the LBP, enlarging the propeller tip clearance, moving forward of the LCB location and increasing the displacement were applied by stepwise to develop the new hull form of DWT 75,000 product oil carrier. Finally a new hull form was developed without the resistance performance loss compared with the parent ship.

• Journal of Positioning, Navigation, and Timing
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• 제1권1호
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• pp.7-14
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• 2012

Due to inaccurate safe navigation estimates, maritime accidents have been occurring consistently. In order to solve this, the precise positioning technology using carrier phase information is used, but due to high buildings near inland waterways or inclination, satellite signals might become weak or blocked for some time. Under this weak signal environment for some time, the GPS raw measurements become less accurate so that it is difficult to search and maintain the integer ambiguity of carrier phase. In this paper, a method to generate code and carrier phase measurements under this environment and maintain resilient navigation is proposed. In the weak signal environment, the position of the receiver is estimated using an inertial sensor, and with this information, the distance between the satellite and the receiver is calculated to generate code measurements using IGS product and model. And, the carrier phase measurements are generated based on the statistics for generating fractional phase. In order to verify the performance of the proposed method, the proposed method was compared for a fixed blocked time. It was confirmed that in case of a weak or blocked satellite signals for 1 to 5 minutes, the proposed method showed more improved results than the inertial navigation only, maintaining stable positioning accuracy within 1 m.

• 산업경영시스템학회지
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• 제45권3호
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• pp.49-56
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• 2022

ROK Navy intends to secure the Korean-type aircraft carrier in order to effectively prepare for various future security threats. In general, the Korean national competency is considered to be at the level of having an aircraft carrier, but it is unclear what scale aircraft carrier would be appropriate. In this study, the efficiency was evaluated through the relative comparison between national competency(national power, economic power) and the scale of aircraft carriers, and the optimal scale of the Korean-type aircraft carrier that could be acquired was presented. A DEA(Data Envelopment Analysis) model was applied to aircraft carriers(19 aircraft carriers in 11 countries) currently in operation and scheduled to be possessed in the world. As input variables, CINC(Composite Index of National Capability) and GDP(Gross Domestic Product), which are the most widely used as indicators of national and economic power, and as output variables, the full-load displacement, length, and width of aircraft carriers were selected. ARIMA(short-term within 5 years) and simple regression(long-term over 5 years) were used to estimate the future national competency of each country at the time of aircraft carriers acquisition. The relative efficiency score of the Korean-type aircraft carrier currently being evaluated is 1.062, and it was evaluated as small-scale aircraft carrier compared to the national competency. Based on Korean national competency, the optimal scale of the Korean-type aircraft carrier calculated by aggregating benchmark groups, is 58,308.1 tons of full-load displacement, 279.4m in length, and 68.3m in width.

• 한국통신학회논문지
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• 제33권4A호
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• pp.440-449
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• 2008

본 논문에서는 Inmarsat M4 시스템의 수신기의 실제 구현에 적합한 16-QAM (Quadrature Amplitude Modulation) carrier recovery loop를 제안한다. Inmarsat M4 시스템 규격에서 권고하는 frequency tolerance는 ${\pm}924\;Hz$ (Signal bandwidth: 33.6 kHz) 로서 이러한 상대적으로 큰 주파수 옵셋 환경에서 안정된 동작이 가능한 carrier recovery loop 설계가 요구된다. 일반적인 PLL(Phase Locked Loop) 만을 이용한 carrier recovery loop는 상대적으로 큰 주파수 옵셋 환경에서 안정적인 성능을 보장할 수 없으며, 이에 따라 본 논문에서는 상대적인 주파수 옵셋이 큰 환경에서도 안정적이 동작이 가능한 Inmarsat M4 시스템을 위한 carrier recovery loop 루프를 제안한다. 제안된 carrier recovery loop는 우선 carrier recovery 이전에 UW 신호 detection 을 위해 주파수 옵셋에 강인한 differential filter 기반의 noncoherent 방식의 detector를 이용하여 UW detection을 수행하였으며, 이후 초기 주파수 옵셋 포착을 위해 UW(Unique Word) 신호를 이용한 차동 방식의 CP(Cross Product)-AFC를 적용하였다. 또한 일반적으로 알려진 16-QAM NDA (Non Data Aided) 방식 대신 안정적인 jitter 성능을 위하여 16-QAM DD(Decision Directed) 방식의 PLL 을 적용하여 위상 추적을 수행하였으며, 성능 검증을 통해 제안된 16-QAM carrier recovery loop가 만족스러운 성능과 신뢰성 있는 동작이 가능함을 입증하였다.

• 소성∙가공
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• 제14권3호
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• pp.207-214
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• 2005

Blanking process is widely used fur producing various structural parts. However, fine blanking technology is frequently used as a single step blanking operation with clean cut surface of a sheared surface because the fractured surface of parts causes serious problems in the final product and therefore it must be removed by the post-processing in case of the conventional blanking. In the present investigation, a fine blanking process was designed within the framework of progressive die to produce a carrier plate assembled within the auto transmission. Finite element analysis of the shearing behavior at the respective stage of the progressive fine blanking was conducted to validate the designed die parameters. Finally the designed progressive fine blanking process was experimentally evaluated by using the machined die.