• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2013년도 춘계학술대회
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• pp.218-222
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• 2013

우리나라와 중국을 비롯한 아시아권과 브라질 칠레 등 남미 간 무역거래량이 지속적으로 증가하고 있으며, 그 주요 품목은 농수산물, 공산품, 광물 등 원자재를 비롯하여 매우 다변화 되고 있는 추세에 있다. 이에 따른 국제물류수단은 주로 항공 및 컨테이너 라이너에 의존하고 있으나 대부분 여러 기항지를 경유하고 있으므로 소요시간이 많이 길고 환적 등 다소 복잡한 수송루트를 거쳐야 하는 애로사항이 있어 화주들이 물류비절감에 애로를 겪고 있다. 이에 본 연구에서는 태평양을 마주하며 대권항법에 따라 지리적으로 인접하고 특히 동북아시아와 남미의 허브로 기능할 수 있는 한국과 에콰도르의 주요 항만을 이용한 두 지역 간의 직항물류망을 개설함으로써 물류에 소요되는 시간과 비용을 절감할 수 있는 방안을 모색해 보고자 한다.

• Journal of Advanced Marine Engineering and Technology
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• 제38권10호
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• pp.1303-1309
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• 2014

In this paper, we present an iterative learning control (ILC) framework for tracking problems with predefined data points that are desired points at certain time instants. To design ILC systems for such problems, a new ILC scheme is proposed to produce output curves that pass close to the desired points. Unlike traditional ILC approaches, an algorithm will be developed in which the control signals are generated by solving an optimal ILC problem with respect to the desired sampling points. In another word, it is a direct approach for the multiple points tracking ILC control problem where we do not need to divide the tracking problem into two steps separately as trajectory planning and ILC controller.The strength of the proposed formulation is the methodology to obtain a control signal through learning law only considering the given data points and dynamic system, instead of following the direction of tracking a prior identified trajectory. The key advantage of the proposed approach is to significantly reduce the computational cost. Finally, simulation results will be introduced to confirm the effectiveness of proposed scheme.

• 한국유체기계학회 논문집
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• 제17권2호
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• pp.30-34
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• 2014

Membrane distillation (MD) is a thermal driven separation process in which separation a hydrophobic membrane is a barrier for the liquid phase, letting the vapor phase pass through the membrane pores. Therefore, a porous and hydrophobic membrane should be used in membrane distillation. MD cannot work if water penetrates into the pores of the membrane (membrane wetting). Accordingly, it is necessary to prevent wetting of MD membranes and to remove water inside the pores of the wetted membranes if possible. In this context, our study aimed to develop methods to recover wetted membranes in MD processes. Poly-vinylidene fluoride (PVDF) membranes were used in this study. A laboratory-scale direct contact MD (DCMD) system was used to examine the effect of operating parameters on wetting. For dewetting the wetted membranes, specific techniques including the use of high temperature air were applied. The performances of the membranes before and after dewetting were compared in terms of flux, salt rejection and liquid entry pressure(LEP). The surface morphology of dewetted membrane was confirmed by scanning electron microscope (SEM).

• Journal of Korean Neurosurgical Society
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• 제60권3호
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• pp.335-347
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• 2017

Intravenous recombinant tissue plasminogen activator had been the only approved treatment for acute ischemic stroke since its approval in 1995. However, the restrictive time window, numerous contraindications, and its low recanalization rate were all limitations of this modality. Under those circumstances, endovascular stroke therapy went through a great evolution during the past two decades of intravenous thrombolysis. The results of the 2013 randomized trials for endovascular stroke therapy were neutral, although they were limited by insufficient imaging screening at enrollment, early-generation devices with less efficacy, and treatment delays. Huge progress was made in 2015, as there were five randomized clinical trials which all demonstrated the safety and efficacy of endovascular stroke treatment. Despite differences in detail patient enrollment criteria, all 5 trials employed key factors for good functional recovery; (1) screening with non-invasive imaging to identify the proximal occlusion and exclude a large infarct core, (2) using highly effective modern thrombectomy devices mainly with stent retriever, and (3) establishment of a fast workflow to achieve effective reperfusion. The results of those trials indicate that modern thrombectomy devices can allow for faster and more effective reperfusion, which can lead to improved clinical outcomes compared to intravenous thrombolysis alone. These advances in mechanical thrombectomy are promising in the global fight against ischemic stroke-related disability and mortality. Two current mainstreams among such mechanical thrombectomy techniques, "stent retriever thrombectomy" and "direct clot aspiration", are the topic of this review. Stent retriever thrombectomy using Solitaire and Trevo retriever will be firstly discussed. And, the commonalities and the differences between two major clot aspiration thrombectomy techniques; a direct aspiration first pass technique (ADAPT) and forced arterial suction thrombectomy (FAST), will be additionally explained. Finally, details regarding the combination of direct clot aspiration and stent retriever thrombectomy, the switching strategy and the Solumbra technique, will be described.

• 한국전자통신학회논문지
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• 제13권6호
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• pp.1161-1168
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• 2018

2018년 4월 27일 역사적인 남북 정상의 판문점 선언을 통해 남과 북은 철도연결을 위한 실질적인 대책들을 마련해 나가기로 합의하였다. 상상이 현실이 되어 당장이라도 부산-유럽 간의 열차가 운행될 것처럼 연일 보도하고 있지만 남한에서 출발한 열차가 북한 철도로 직결 운행하고 대륙철도로 국경을 통과하는 운영노선은 지금까지 한국철도가 취급해보지 못한 미지의 영역으로 본격적인 운행을 위해 상당한 부분을 면밀히 검토해야 한다. 또한 철도교통은 타 교통수단과 달리 종합적인 네트워크 시스템으로 서로 다른 철도망의 직결운행을 위한 표준화와 기술적 조화가 매우 중요하다. 본 논문에서는 남북철도 연결대비 직결운행을 위해 철도 상호운용성에서 주도적인 역할을 하고 있는 유럽사례를 살펴보고, 이를 통하여 남북철도 직결운행을 위한 실질적인 상호운용성 확보에 대하여 고찰하였다.

• 한국멀티미디어학회논문지
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• 제19권5호
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• pp.910-917
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• 2016

Sensors have limited resources in sensor networks, so efficient use of energy is important. Representative clustering methods, LEACH, LEACHC, TEEN generally use direct transmission methods from cluster headers to the sink node to pass collected data. However, the communication distance of the sensor nodes at low cost and at low power is not long, it requires a data transfer through the multi-hop to transmit data to the sink node. In the existing cluster-based sensor network studies, cluster process and route selection process are performed separately in order to configure the routing path to the sink node. In this paper, in order to use the energy of the sensor nodes that have limited resources efficiently, a cluster-based multi-hop routing protocol which merges the clustering process and routing process is proposed. And the proposed method complements the problem of uneven cluster creation that may occur in probabilistic cluster methods and increases the energy efficiency of whole sensor nodes.

• 한국정밀공학회지
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• 제24권11호
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• pp.144-153
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• 2007

In order to generate the input data for rapid prototyping, a new approach which is based on the implicit surface interpolation method is presented. In the method a surface is reconstructed by creating smooth implicit surface from unorganized cloud of points through which the surface should pass. In the method an implicit surface is defined by the adaptive local shape functions including quadratic polynomial function, cubic polynomial function and RBF(Radial Basis Function). By the reconstruction of a surface, various types of error in raw STL file including degenerated triangles, undesirable holes with complex shapes and overlaps between triangles can be eliminated automatically. In order to get the slicing data for rapid prototyping an efficient intersection algorithm between implicit surface and plane is developed. For the direct usage for rapid prototyping, a robust transformation algorithm for the generation of complete STL data of solid type is also suggested.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2198-2202
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• 2005

In this paper we have presented a condition monitoring method of check valve using neural network. The acoustic emission sensor was used to acquire the condition signals of check valve in direct vessel injection (DVI) test loop. The acquired sensor signal pass through a signal conditioning which are consisted of steps; rejection of background noise, amplification, analogue to digital conversion, extract of feature points. The extracted feature points which represent the condition of check valve was utilized input values of fault diagnosis algorithms using pre-learned neural network. The fault diagnosis algorithm proceeds fault detection, fault isolation and fault identification within limited ranges. The developed algorithm enables timely diagnosis of failure of check valve’s degradation and service aging so that maintenance and replacement could be preformed prior to loss of the safety function. The overall process has been experimented and the results are given to show its effectiveness.

• 반도체디스플레이기술학회지
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• 제14권4호
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• pp.88-91
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• 2015

In this paper, we have designed and fabricated a BPF (Band Pass Filter) for 5.8GHz Microwave Wireless Power Transmission. We $used{\lambda}g/2$ open-circuited stubs in addition to T-shaped transmission lines for the BPF. This BPF removes harmonics caused by diodes of RF-DC converter, and thus the RF-DC converter converts more RF power to the DC. The performance of the BPF was measured and shown through direct comparison of voltages converted by the doubler as a RF-DC Converter with and without the BPF.

• 조명전기설비학회논문지
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• 제21권2호
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• pp.34-39
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• 2007

UWB(Ultra Wide Band) system for high speed and high accurate location has been studying actively. This paper presents the design and implementation of RF transceiver for DS-CDMA(Direct Sequence-Code Division Multiple Access) UWB device. Major components of RF transceiver such as Low Noise Amplifier(LNA) and Band Pass Filter(BPF) are designed and then fabricated to meet wideband characteristics. The RF transceiver was implemented by the use of the fabricated components and commercial devices after carrying out performance simulation. Through the performance evaluation of the UWB RF transceiver with W-CDMA signal, the approach of design, implementation and evaluation of RF transceiver which is available to DS-CDMA UWB system is verified.