• 항공우주시스템공학회지
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• 제14권2호
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• pp.1-11
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• 2020

Detecting obstacles and generating a suitable path to avoid obstacles in real time is a prime mission requirement for UAVs. In areas, close to buildings and people, detecting obstacles in the path and estimating its own position (egomotion) in GPS degraded/denied environments are usually addressed with vision-based Simultaneous Localization and Mapping (SLAM) techniques. This presents possibilities and challenges for the feasible path generation with constraints of vehicle dynamics in the configuration space. In this paper, a near real-time feasible path is shown to be generated in the ORB-SLAM framework using a chain-based path planning approach in a force field with dynamic constraints on path length and minimum turn radius. The chain-based path plan approach generates a set of nodes which moves in a force field that permits modifications of path rapidly in real time as the reward function changes. This is different from the usual approach of generating potentials in the entire search space around UAV, instead a set of connected waypoints in a simulated chain. The popular ORB-SLAM, suited for real time approach is used for building the map of the environment and UAV position and the UAV path is then generated continuously in the shortest time to navigate to the goal position. The principal contribution are (a) Chain-based path planning approach with built in obstacle avoidance in conjunction with ORB-SLAM for the first time, (b) Generation of path with minimum overheads and (c) Implementation in near real time.

• 예술인문사회 융합 멀티미디어 논문지
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• 제8권6호
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• pp.563-570
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• 2018

1900년대부터 시작된 노벨상 제도를 통하여 세계적으로 천 명 이상의 수상자를 배출하였다. 그러나 한국은 과학 분야에서 수상자를 배출하지 못하고 있다. 노벨 과학상이 가능한 토양을 만들기 위하여 과학행정, 관료문화, 공교육 등 여러 가지 측면에서 많은 고민과 개선이 필요하다. 과학행정 분야에서는 성장주의 및 권위주의가 큰 걸림돌이 되고 있는 것으로 보인다. 과학기술을 정책적 수단으로 성장시킬 수 있으며 과학기술의 성과는 바로 돈으로 연결된다는 생각은 노벨상을 위한 건강한 토양이 아니다. 단기성과 위주의 과학정책과 정량적 평가 중심의 연구지원 체계도 걸림돌이 된다. 창의성과 도전의 가치를 드높이는 학교 교육이 필요하다. 실패에 대해 관용하고 시행착오를 통해 얻은 경험의 가치를 높게 평가하는 사회적 공감대가 필요하다. 실패를 각오하고 연구를 해야 성공할 수 있다. 돈이 되지 않는 것을 연구하려고 해야 돈이 될 수 있다. 노벨상을 의식하지 않는 연구해야 노벨상에 접근할 수 있다.

• 한국토양비료학회지
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• 제45권3호
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• pp.421-427
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• 2012

Nepal is one of the least urbanized countries in the world where more than 80% of the total population live in rural areas. In recent years, the rate of urbanization became rampant which ultimately accelerated immense pressure on municipal services, especially on managing the ever increasing amount of wastes. Due to lack of technology, infrastructure and financial capacity management of increasing amount of solid waste has become a major challenge in municipalities of Nepal. The indiscriminate dumping of solid wastes already affected the urban environment by creating a serious occupational health and environmental hazard to the vicinity of the dumping sites. However, there is great possibility of recovering methane from the landfill sites since the typical Nepalese municipal solid waste contains more than 65% of organic wastes. Despite having enormous potential of generating electricity from hydropower, Nepal is facing acute shortage of energy. Therefore, comprehensive scientific research and development is necessary for making solid waste to environmentally friendly by converting waste to the energy.

• Journal of the Korean Data and Information Science Society
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• 제24권5호
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• pp.1077-1088
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• 2013

High-dimensional data analysis arises from almost all scientific areas, evolving with development of computing skills, and has encouraged penalized estimations that play important roles in statistical learning. For the past years, various penalized estimations have been developed, and the least absolute shrinkage and selection operator (LASSO) proposed by Tibshirani (1996) has shown outstanding ability, earning the first place on the development of penalized estimation. In this paper, we first introduce a number of recent advances in high-dimensional data analysis using the LASSO. The topics include various statistical problems such as variable selection and grouped or structured variable selection under sparse high-dimensional linear regression models. Several unsupervised learning methods including inverse covariance matrix estimation are presented. In addition, we address further studies on new applications which may establish a guideline on how to use the LASSO for statistical challenges of high-dimensional data analysis.

• Journal of the Korean Data and Information Science Society
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• 제24권5호
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• pp.1063-1076
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• 2013

현대 과학기술의 발전으로 빅데이터의 시대가 도래하였다, 이러한 빅데이터는 여러가지 과학적 문제에 대한 해답을 제공하지만 반면에 이로 인해 새로운 도전에 직면하고 있다. 마이크로어레이 자료와 같은 고차원자료는 이러한 빅데이터에서 흔히 볼 수 있는 유형중의 하나이다. 본 논문에서는 고차원 자료분석에 많이 쓰이고 있는 대역검정과 동시검정, 그리고 이의 응용에 대한 소개를 한다.

• Bulletin of the Korean Chemical Society
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• 제24권6호
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• pp.797-801
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• 2003

One of the largest challenges for quantum chemistry today is to obtain accurate results for large complex molecular systems, and a variety of approaches have been proposed recently toward this goal. We have developed the ONIOM method, an onion skin-like multi-level method, combining different levels of quantum chemical methods as well as molecular mechanics method. We have been applying the method to many different large systems, including thermochemistry, homogeneous catalysis, stereoselectivity in organic synthesis, solution chemistry, fullerenes and nanochemistry, and biomolecular systems. The method has recently been combined with the polarizable continuum model (ONIOM-PCM), and was also extended for molecular dynamics simulation of solution (ONIOM-XS). In the present article the recent progress in various applications of ONIOM and other electronic structure methods to problems of homogeneous catalyses and nanochemistry is reviewed. Topics include 1. bond energies in large molecular systems, 2. organometallic reactions and homogeneous catalysis, 3. structure, reactivity and bond energies of large organic molecules including fullerenes and nanotubes, and 4. biomolecular structure and enzymatic reaction mechanisms.

• KSBB Journal
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• 제17권3호
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• pp.213-227
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• 2002

To date, the majority of biosensor technologies use binding components such as enzymes antibodies, nucleic acids and protein ligands. In contrast, the goal underlying the use of cells and tissues of animals and plants for a sensor system is to obtain systems capable of extracting information based on the biological activity, mechanisms of action and consequences of exposure to a chemical or biological agent of interest. These systems enable the interrogation of more complex biological response and offer the potential to gather higher information content from measuring physiologic and metabolic response. In these articles, same of the recent trends and applications of microbial biosensors in environmental monitoring and for use in food and fermentations have been reviewed. This endeavor presents many technological challenges to fabricate new microbial biosensors for other scientific field.

• Journal of Microbiology and Biotechnology
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• 제25권2호
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• pp.145-151
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• 2015

Graphene is a next-generation biomaterial with increasing biomedical applicability. As a new class of one-atom-thick nanosheets, it is a true two-dimensional honeycomb network nanomaterial that attracts interest in various scientific fields and is rapidly becoming the most widely studied carbon-based material. Since its discovery in 2004, its unique optical, mechanical, electronic, thermal, and magnetic properties are the basis of exploration of the potential applicability of graphene. Graphene materials, such as graphene oxide and its reduced form, are studied extensively in the biotechnology arena owing to their multivalent functionalization and efficient surface loading with various biomolecules. This review provides a brief summary of the recent progress in graphene and graphene oxide biological research together with current findings to spark novel applications in biomedicine. Graphene-based applications are progressively developing; hence, the opportunities and challenges of this rapidly growing field are discussed together with the versatility of these multifaceted materials.

• Journal of information and communication convergence engineering
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• 제6권3호
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• pp.249-254
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• 2008

Moored ocean buoys are technically feasible approach for making sustained time series observation in the oceans and will be an important component of any long-term ocean observing system. The 3M disc buoy carried Zeno 3200, MCCB, Orbcomm, Global Star and Bluetooth module. The deployments have relied on Orbcomm and Global Star as the primary satellite communications system. In addition to detailing our practical experience in the use of Orbcomm and Global Star as high latitudes, we will present some of scientific sensor results regarding real-time oceanographic and meteorological parameters such as wind speed, wave height and etc. In this paper we present the design and implementation of a small-scale buoy sensor network. One of the major challenges is that the network is hard to access after its deployment and hence both hardware and software must be robust and reliable.

• Journal of Electrochemical Science and Technology
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• 제11권3호
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• pp.195-219
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• 2020

Today, rechargeable lithium-ion batteries are an essential portion of modern daily life. As a promising alternative to traditional energy storage systems, they possess various advantages. This review attempts to provide the reader with an indepth understanding of the working mechanisms, current technological progress, and scientific challenges for a wide variety of lithium-ion battery (LIB) electrode nanomaterials. Electrochemical thermodynamics and kinetics are the two main perspectives underlying our introduction, which aims to provide an informative foundation for the rational design of electrode materials. Moreover, both anode and cathode materials are clarified into several types, using some specific examples to demonstrate both their advantages and shortcomings, and some improvements are suggested as well. In addition, we summarize some recent research progress in the rational design and synthesis of nanostructured anode and cathode materials, together with their corresponding electrochemical performances. Based on all these discussions, potential directions for further development of LIBs are summarized and presented.