• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.6-10
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• 2007

Classification of hyperspectral images is challenging. A very high dimensional input space requires an exponentially large amount of data to adequately and reliably represent the classes in that space. In other words in order to obtain statistically reliable classification results, the number of necessary training samples increases exponentially as the number of spectral bands increases. However, in many situations, acquisition of the large number of training samples for these high-dimensional datasets may not be so easy. This problem can be overcome by using multiple classifiers. In this paper we compared the effectiveness of two approaches for creating multiple classifiers, feature selection and feature extraction. The methods are based on generating multiple feature subsets by running feature selection or feature extraction algorithm several times, each time for discrimination of one of the classes from the rest. A maximum likelihood classifier is applied on each of the obtained feature subsets and finally a combination scheme was used to combine the outputs of individual classifiers. Experimental results show the effectiveness of feature extraction algorithm for generating multiple classifiers.

• Structural Engineering and Mechanics
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• 제86권1호
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• pp.109-118
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• 2023

Any place where exercise is common, such as a club, sports hall, or school, is considered a place for teaching sports. When doing sports, a very safe environment for sports should be chosen. The athlete should consider the safety of sports facilities and equipment, and if there is a defect, he should refrain from exercising in these places. The safety of sports facilities is very effective in creating people's sports activities, with the benefits of staying away from physical harm, enjoying sports, and having mental peace. Everyone has the right to participate in sports and recreation and to ensure that they enjoy a safe environment. The ability to manage and solve issues that may arise plays the most critical role in creating a safe environment. The quality of construction materials used for the construction of sports facilities is of great importance. In this work, the resistance and water repellency of concrete constituents for the construction of sports buildings have been investigated by nanoscience. Nano-concrete material solves the main problem of concrete surfaces, i.e., the entry of water and humidity into the structure. It also gives it a self-cleaning ability with its water repellency. Nanoparticles are placed between pores and cover the cracks, which causes roughness in the surface structure of concrete. The high roughness of the surface of the coated concrete caused its super-hydrophobicity. In hydrophobic surfaces, the higher the contact angle, the more hydrophobic the surface will be. In order to investigate the hydrophobic properties, silica nanoparticles, silica nanoparticles, and fly ash were prepared on concrete, and their properties were analyzed.

• 실천공학교육논문지
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• 제15권2호
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• pp.321-330
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• 2023

본 논문에서는 특정 도메인의 온톨로지 구성에 필요한 용어 간의 다양한 관계를 추출하여 자동으로 온톨로지를 생성하는 방법을 제안하고자 한다. 추출된 관계를 온톨로지의 구조에 공리 집합으로 인코딩하여 온톨로지로 구성한다. 효율적으로 해결하기 위해 집합의 검색 공간을 정수 프로그래밍 문제로 표현하며, 최적화를 위해 별로 도움이 되지 않는 규칙은 제거하는 단순한 축소를 사용하여 행렬을 감소시킨다. 결론적으로 본 논문에서는 주어진 데이터를 이용하여 패턴을 일반화하고, 유용한 패턴을 유지하면서 검색 공간을 줄이는 방법을 제시하며, 구조화된 온톨로지로 구성하는 알고리즘을 적용하여 추출된 관계를 이용해 자동으로 효율적인 온톨로지로 생성하는 방법을 제안한다.

• 영재교육연구
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• 제23권6호
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• pp.1099-1115
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• 2013

지식의 생성 주체로서 집단지성이 주목받고 있다. 집단지성으로 문제를 해결하기 위해서는 협업이 필요한데 협업을 위한 기본 조건은 정보의 공유이다. 이 연구에서는 4명의 과학영재 학생들을 대상으로 불일치 상황을 제시하고 이를 과학적으로 설명하도록 요구한 후 그들의 문제해결과정을 분석함으로써 과학영재들이 협업적 문제해결과정에서 무엇을 공유하는지를 알아보았다. 연구 결과, 과학영재들은 문제발견과정에서 전제와 문제를 공유하였고, 가설 생성과정에서는 문제해결의 목표와 이 목표에 도달할 수 있는 수단을 공유하여 가설을 생성하기 위한 조작자 인출에 이용하였다. 생성된 가설이 평가되는 과정에서는 해결방법의 평가기준으로서 제약조건과, 이를 이용한 평가의 결과를 공유하였다. 이는 집단이 생각의 공유를 통해 스스로 지식을 창출하고 자신들의 개념을 변화시켜 나가는 것을 의미한다. 이러한 문제해결과정을 통한 자발적인 개념변화는 영재교육에 시사점을 제공한다.

• Journal of Computing Science and Engineering
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• 제2권1호
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• pp.44-73
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• 2008

There is general agreement that the problem of data semantics has to be addressed for XML data to become machine-processable. This problem can be tackled by defining a semantic mapping between an XML schema and an ontology. Unfortunately, creating such mappings is a tedious, time-consuming, and error-prone task. To alleviate this problem, we present a solution that heuristically discovers semantic mappings between XML schemas and ontologies. The solution takes as input an initial set of simple correspondences between element attributes in an XML schema and class attributes in an ontology, and then generates a set of mapping formulas. Once such a mapping is created, it is important and necessary to maintain the consistency of the mapping when the associated XML schema and ontology evolve. In this paper, we first offer a mapping formalism to represent semantic mappings. Second, we present our heuristic mapping discovery algorithm. Third, we show through an empirical study that considerable effort can be saved when discovering complex mappings by using our prototype tool. Finally, we propose a mapping maintenance plan dealing with schema evolution. Our study provides a set of effective solutions for building sustainable semantic integration systems for XML data.

• Archives of Reconstructive Microsurgery
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• 제9권2호
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• pp.158-163
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• 2000

Over the past several years, countless patients have benefitted from the use of leeches in microsurgery. As we know, leeches are used to overcome the problem of venous congestion by creating prolonged localized bleeding uniquely characteristics of leech bite. Venous congestion, a common complication of digital replantation, often has been treated through surgical repair like arteriovenous anastomosis. The leech produces a number of important substances which contribute to the special property of the bite, including an anticoagulant, a local vasodilator and local anesthetics. The bite usually bleeds for 1 to 2 hours and under special circumstances may bleed for up to 24 hours. So venous congestion is relieved. However, leeches increase the possibility of infection through their gut content. Infection associated medical leech application is significant risk. Other risk include allergic reaction, adverse psychologic reaction and blood loss requiring transfusion. The 65 cases of medical leech application were performed between August, 1997 and May, 2000 according to an established protocol. The complication were 18 cases ; infection (13 cases), hemorrhage (2 cases), allergic reaction (1 case), psychologic problem (1 case) and hypochromic anemia (1 case). Then our study was performed on the base of indication. As a result, Aeromonas hydrophilia was cultured from gut of medical leech and Klebsiella, Staphylococcus and Pseudomonas were cultured from media. We present the clinical risk-benefit of the medical leech therapy through several cases following digital replantation.

• 시스템엔지니어링학술지
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• 제18권2호
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• pp.117-125
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• 2022

In the early 2000s, the rapid decline in the fertility rate resulted in a decrease in military resources to maintain the conscription system. In addition, there has been a further decline in the fertility rate in recent years. So, it is necessary to efficiently utilize military resources to prepare for future problems. The Republic of Korea Navy is planning to reduce the number of crew to operate the newly built warships to prepare for this trend of decreasing in troop resources. However, if the number of crew is reduced without reviewing the appropriate number of crew for the operation of the warship, a bigger problem may be encountered in the future. In order to solve this problem, research is being conducted to examine whether the number of crew aboard a warship is appropriate using simulation. However, it is difficult to create a crew simulation model due to the lack of detailed data related to crew operation. In this study, to solve this problem, a method of generating quantitative data using qualitative survey results was suggested, and the process of creating a crew simulation model was performed using this.

• International Journal of Aeronautical and Space Sciences
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• 제10권1호
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• pp.75-82
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• 2009

In this parer, we propose a new way of improving DGNSS service using combination of multiple SBAS information. Because SBAS uses Geostationary Earth Orbit (GEO) satellites, it has very large coverage but it can be unavailable in urban canyon because of visibility problem. R. Chen solved this problem by creating Virtual Reference Stations (VRS) using the SBAS signal [1]. VRS converts SBAS signal to RTCM signals corresponding its location, and broadcast the converted RTCM signals over the wireless internet. This method can solve the visibility problem cost effectively. Furthermore it can solve DGNSS coverage problem by creating just a transmitter instead of a reference station. Developing above method, this paper proposes the methods that integrate two or more SEAS signals into one RTCM signal and broadcast it. In Korea, MSAS signal is available even though it is not officially certified for Korean users. As a Korean own SBAS-like system, there is the internet-based KWTB (Korean WADGPS Test Bed) which we developed and released at ION GNSS 2006. As a result, virtually two different SBAS corrections are available in Korea. In this paper, we propose the integration methods for these two independent SBAS corrections and present the test results using the actual measurements from the two systems. We present the detailed algorithm for these two methods and analyze the features and performances of them. To verify the proposed methods, we conduct the experiment using the logged SBAS corrections from the two systems and the RINEX data logged at Dokdo monitoring station in Korea. The preliminary test results showed the improved performance compared to the results from two independent systems, which shows the potential of our proposed methods. In the future, the newly developed SBASs will be available and the places which can access the multiple SBAS signals will increase. At that time, the integration or combination methods of two or more SBASs will become more important. Our proposed methods can be one of the useful solutions for that. As an additional research, we need to extend this research to the system level integration such as the concept of the decentralized W ADGPS.

• 벤처창업연구
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• 제13권4호
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• pp.169-181
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• 2018

지속적으로 심화되고 있는 글로벌 경쟁 환경 하에서 많은 기업들은 공유가치 창출 (CSV, Creating Shared Value)을 통해 사회혁신 분야에서 새로운 사업 기회를 모색하고 있다. 사회혁신을 추구함에 있어 해결하고자 하는 문제를 명확히 도출하고, 문제의 원인을 파악하는 것이 사회혁신의 핵심 출발점이다. 수많은 문제해결 방법론 중에 최근 다양한 분야에서 가장 많은 관심을 받는 것은 디자인 씽킹 (Design Thinking)이다. 디자인 씽킹은 인간의 필요에 공감하고 대중도 인식하지 못하는 잠재적 욕구를 발굴하여 해결하는 창의적 문제해결 방법론으로 비즈니스 혁신도구로도 사용되지만 사회 문제를 해결하는 사회혁신을 위한 도구로서 활발히 이용되고 있다. 그러나 디자인 씽킹 프로젝트를 수행하는 많은 주체들이 겪는 어려움 중의 하나가 관찰 데이터의 효율적 분석이 어렵다는 것이다. 오프라인 방식으로만 데이터를 분석할 경우 대량의 데이터를 처리하는데 시간이 오래 걸리며, 비정형데이터의 경우 처리가 어려워 관찰을 통해 어렵게 수집한 데이터로부터 문제점을 발견하는데 어려움을 호소한다. 이에 본 연구는 디자인 씽킹 프로세스의 한계점을 보완하고자 사회혁신을 위한 디자인 씽킹 프로젝트의 관찰단계에서 수집한 데이터 분석이 보다 과학적으로 이루어질 수 있도록 질적 자료 분석과 양적 자료 분석 방법을 균형 있게 사용하는 통합방법론을 제시하고자 한다.

• 한국과학교육학회지
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• 제26권6호
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• pp.765-774
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• 2006

이 연구의 목적은 과학적 문제발견 능력을 신장시키기 위한 수업 방향을 제시하는 것이다. 이를 위해서 연구 대상자들은 협동 활동과 개별 활동을 통해 낮게 구조화된 과학적 문제 상황에서의 문제발견 과제를 수행하였으며, 문제발견 활동에 대한 심층적인 분석을 하였다. 분석 결과, 협동 문제발견 활동은 '문제 상황 탐색', '기존 지식 및 경험 표출', '잠정적 문제의 적절성 논의', '다양한 문제 생성', '최선의 문제 선택'의 다섯 단계를 거치는 것으로 나타났다. 또한 협동 문제발견 활동은 기존 지식이나 직간접 경험에 크게 의존하며, 문제 상황과 관련된 다양한 과학적 개념이 자연스럽게 표출되는 것으로 나타났다. 협동 활동을 통해 발견된 문제에 대한 창의성 요소 점수와 독창적 문제선택에 대한 일치 정도는 대체로 높은 편으로 나타났다. 또한 열린 문제 상황에서 발견된 문제의 유형이 닫힌 상황보다 더 다양한 것으로 나타났다. 또한 학생들은 문제발견 활동이 과학적 개념이나 사고력 및 탐구 능력을 신장시키는데 긍정적인 영향을 준 것으로 인식하고 있었다. 따라서 교사는 첫째, 문제발견에 필요한 지식이나 정보를 탐색할 수 있는 교육적 환경을 조성해야 한다. 둘째, 과학 지식과 경험의 폭을 넓힐 수 있는 다양한 기회를 제공해야 한다. 셋째, 학생들의 지식과 경험을 자유롭게 표출할 수 있는 수업 분위기를 조성해야 한다.