검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 267

        21.
        2019.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is carried out on the structural improvement of military mobile kitchen trailer for the betterment of fighting power by serving meals to solider in right time. To recognize the real problems of field kitchen trailer, the heat transfers from burner for soup cooker were compared with each other. By the test, the necessity of improvement was deduced. To examine the cause of cooking time, it was determined by the characteristic diagram. Based on the cause, there are two types of kitchen trailer's burner structures. To verify the improved structures, it was carried out for the performance test. As the results, the time did not become longer and the temperature rising rate per minute increased. This study is expected to be devoted to the future improvement of military mobile kitchen trailer.
        4,000원
        23.
        2019.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A wireless sensor network is emerging technology and intelligent wireless communication paradigm that is dynamically aware of its surrounding environment. It is also able to respond to it in order to achieve reliable and efficient communication. The dynamical cognition capability and environmental adaptability rely on organizing dynamical networks effectively. However, optimally clustering the cognitive wireless sensor networks is an NP-complete problem. The objective of this paper is to develop an optimal sensor network design for maximizing the performance. This proposed Ranking Artificial Bee Colony (RABC) is developed based on Artificial Bee Colony (ABC) with ranking strategy. The ranking strategy can make the much better solutions by combining the best solutions so far and add these solutions in the solution population when applying ABC. RABC is designed to adapt to topological changes to any network graph in a time. We can minimize the total energy dissipation of sensors to prolong the lifetime of a network to balance the energy consumption of all nodes with robust optimal solution. Simulation results show that the performance of our proposed RABC is better than those of previous methods (LEACH, LEACH-C, and etc.) in wireless sensor networks. Our proposed method is the best for the 100 node-network example when the Sink node is centrally located.
        4,000원
        24.
        2019.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        한국산 제비나방과 쌍꼬리나방아과의 3미기록종인Europlema nubifasciaria (Leech), Dysaethria meridiana (Inoue), Phazaca theclata (Guenée)을 보고한다. Europlema leleji는 Epiplema nubifasciaria의 동종이명으로 판명되었고, 후자는 Europlema속으로 새롭게 편입된다. Europlema nubifasciaria의 암컷생식기를 처음으로 기재한다. 채집된 종의 성충과 생식기의 사진을 제공한다.
        4,000원
        25.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 무전해도금법을 이용한 Pd coating 기술을 활용하여 폐수처리를 위한 전기분해 공정에 anode로의 적용을 목적으로 Ti-mesh 기반 전극을 제조하였다. 제조된 Pd/Ti-mesh 전극은 염색염료인 RO16을 대표로 그 제거성능을 평가하였으며, 전극 제조조건을 다르게 하여 내구성 및 성능을 극대화한 결과 coating 조건은 성능에 크게 영향을 미치지 않았지만, Pd coating 후 열처리 공정의 경우 성능에 크게 영향을 미쳤으며, 내구성 역시 증진됨을 확인하였다. 또한 Ir, Ru, Ta을 복합화하여 성능 및 내구성을 극대화하고자 하였으나, coating법의 한계로 layer의 thickness가 증가함에 따라 저항이 커졌으며, 이에 따라 성능이 감소함을 확인하였다.
        4,200원
        26.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        우리는 오리온 분자운 복합체의 북부 필라멘트(이하 NF)에 대하여 12CO (J=1-0) 분자선의 자료를 이용하여 은하 평면이 분자의 운동과 운동학에 미치는 영향을 연구하였다. 6 m 서울대학교 전파망원경(Seoul Radio Astronomy Observatory, SRAO)을 이용하여 2arcmin 공간분해능으로 은하면으로부터 먼 순서로 NF1, NF2, NF3 세 곳을 총 270시간 동안 관측된 자료를 사용하였다. 은하면과 OMC NF는 12CO (J=2-1) 경우 3% 밀도에서, 티끌의 경우 9% 밝기 수준에서 자기장을 따라 서로 연결되어 있었다. 12CO (J=1-0), 12CO (J=2-1), 성간 티끌 관측결과를 비교해본 결과, 세 경우 모두 NF3에서는 고루 분포했지만, NF1과 NF2에서는 비교적 밀도가 높은 특정 영역에서만 함께 나타났다. NF는 단일 구조를 보였으며, NF1에서는 부분 수축 운동을, NF2에서는 하단에서 회전 운동이 나타났고, NF3에서는 유일하게 명확히 자기장에 연관된 나선형 회전이 보였다. 위치-속도 분석 결과, 12CO (J=1-0)를 비롯한 물질들은 NF2와 NF3을 따라 은하면을 향하여 흐를 가능성이 있음을 확인할 수 있었다. 은하면을 향하여 물질이 흐르는 명백한 원인을 이번 연구결과에서 볼 수 없었지만 추후의 더 정교한 관측결과가 NF1과 NF2 상단부의 회전 운동을 확인 할 수 있겠다.
        4,600원
        27.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        K-means algorithm is one of the most popular and widely used clustering method because it is easy to implement and very efficient. However, this method has the limitation to be used with fixed number of clusters because of only considering the intra-cluster distance to evaluate the data clustering solutions. Silhouette is useful and stable valid index to decide the data clustering solution with number of clusters to consider the intra and inter cluster distance for unsupervised data. However, this valid index has high computational burden because of considering quality measure for each data object. The objective of this paper is to propose the fast and simple speed-up method to overcome this limitation to use silhouette for the effective large-scale data clustering. In the first step, the proposed method calculates and saves the distance for each data once. In the second step, this distance matrix is used to calculate the relative distance rate (Vj) of each data j and this rate is used to choose the suitable number of clusters without much computation time. In the third step, the proposed efficient heuristic algorithm (Group search optimization, GSO, in this paper) can search the global optimum with saving computational capacity with good initial solutions using Vj probabilistically for the data clustering. The performance of our proposed method is validated to save significantly computation time against the original silhouette only using Ruspini, Iris, Wine and Breast cancer in UCI machine learning repository datasets by experiment and analysis. Especially, the performance of our proposed method is much better than previous method for the larger size of data.
        4,000원
        28.
        2018.05 구독 인증기관·개인회원 무료
        SiHCl3를 제조하는 공정에서 배출되는 클로로실란 혼합가스 중 수소의 재이용을 위하여 분리공정이 필수적이며, Pd계 분리막이 사용될 수 있다. 일반적인 Pd분리막의 경우 300°C 이하에서 수소 흡착에 의한 취성문제와 공존하는 불순물가스에 의한 손상문제가 있을 수 있다. 따라서 본 연구에서는 이를 해결하고자 Pd layer 위에 Ru을 무전해 도금하여 Pd/Ru 복합 분리막을 제조하였고 저온에서 수소 투과도 및 안정성을 평가한 결과 180°C에서 50일 동안 수소에 의한 취성이 발생하지 않았으며 1.8 m3m-2h-1의 안정적인 투과량을 나타내었고. 또한 5% HCl, 0.5% SiHCl3가 포함된 가스를 225°C의 온도에서 2 bar로 주입하였을 때 9 hr 동안 Pd/Ru 복합 분리막이 손상되지 않고 수소의 투과량이 2.0 m3m-2h-1 이상으로 유지됨을 확인하였다.
        30.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, it is estimated that ceramic membrane process which can operate stably in harsh conditions replacing existing organic membrane connected with coagulation, sedimentation etc. . Jar-test was conducted by using artificial raw water containing kaolin and humic acid. It was observed that coagulant (A-PAC, 10.6%) 4mg/l is the optimal dose. As a results of evaluation of membrane single filtration process (A), coagulation-membrane filtration process (B) and coagulation-sedimentation-membrane filtration process (C), TMP variation is stable regardless of in Flux 2 m3/m2・day. But in Flux 5 m3/m2・day, it show change of 1-89.3 kpa by process. TMP of process (B) and (C) is increased 11.8, 0.6 kpa each. But, the (A) showed the greatest change of TMP. When evaluate (A) and (C) in Flux 10 m3/m2・day, TMP of (A) stopped operation being exceeded 120 kpa in 20 minutes. On the other hand, TMP of (C) is increased only 3 kpa in 120 minutes. Through this, membrane filtration process can be operated stably by using the linkage between the pretreatment process and the ceramic membrane filtration process. Turbidity of treated water remained under 0.1 NTU regardless of flux condition and DOC and UV254 showed a removal rate of 65-85%, 95% more each at process connected with pretreatment. Physical cleaning was carried out using water and air of 500kpa to show the recovery of pollutants formed on membrane surface by filtration. In (A) process, TMP has increased rapidly and decreased the recovery by physical cleaning as the flux rises. This means that contamination on membrane surface is irreversible fouling difficult to recover by using physical cleaning. Process (B) and (C) are observed high recovery rate of 60% more in high flux and especially recovery rate of process (B) is the highest at 95.8%. This can be judged that the coagulation flocs in the raw water formed cake layer with irreversible fouling and are favorable to physical cleaning. As a result of estimation, observe that ceramic membrane filtration connected with pretreatment improves efficiency of filtration and recovery rate of physical cleaning. And ceramic membrane which is possible to operate in the higher flux than organic membrane can be reduce the area of water purification facilities and secure a stable quantity of water by connecting the ceramic membrane with pretreatment process.
        4,000원
        31.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        한국산 뿔나방과의 2미기록종인Helcystogramma compositaepictum (Omelko et Omelko)와Paralida triannulata Clarke을 보고한다. Paralida Clarke속은 국내에서 처음 기록된다. 성충과 생식기의 사진을 제공하는 한편, 분포 정보를 논하였다.
        3,000원
        32.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Data clustering is one of the most difficult and challenging problems and can be formally considered as a particular kind of NP-hard grouping problems. The K-means algorithm is one of the most popular and widely used clustering method because it is easy to implement and very efficient. However, it has high possibility to trap in local optimum and high variation of solutions with different initials for the large data set. Therefore, we need study efficient computational intelligence method to find the global optimal solution in data clustering problem within limited computational time. The objective of this paper is to propose a combined artificial bee colony (CABC) with K-means for initialization and finalization to find optimal solution that is effective on data clustering optimization problem. The artificial bee colony (ABC) is an algorithm motivated by the intelligent behavior exhibited by honeybees when searching for food. The performance of ABC is better than or similar to other population-based algorithms with the added advantage of employing fewer control parameters. Our proposed CABC method is able to provide near optimal solution within reasonable time to balance the converged and diversified searches. In this paper, the experiment and analysis of clustering problems demonstrate that CABC is a competitive approach comparing to previous partitioning approaches in satisfactory results with respect to solution quality. We validate the performance of CABC using Iris, Wine, Glass, Vowel, and Cloud UCI machine learning repository datasets comparing to previous studies by experiment and analysis. Our proposed KABCK (K-means+ABC+K-means) is better than ABCK (ABC+K-means), KABC (K-means+ABC), ABC, and K-means in our simulations.
        4,000원
        34.
        2017.11 구독 인증기관·개인회원 무료
        The potential application of palladium-ruthenium composite membranes to the separation of hydrogen from chlorosilane gases in silicon-based industries was investigated. Ru/Pd/Al2O3/PSS membranes were prepared by electroless plating. Hydrogen permeation tests and temperature programmed desorption analysis revealed that the addition of a Ru over layer on Pd changed the hydrogen adsorption characteristics, resulting in improved stability of the membrane at low temperatures. The Ru/Pd/Al2 O3/PSS composite membrane had a stable hydrogen permeation flux of 1.8 m3m-2h-1 over a period of 1,200 h at 180°C without suffering hydrogen embrittlement. After exposure to impurities such as HCl and SiHCl3 , the hydrogen permeation flux of the Ru/Pd/Al2 O3/PSS composite membrane was stable over a period of 9h with feed pressure of 2.0 bar at 225°C.
        35.
        2017.10 구독 인증기관·개인회원 무료
        가리왕산은 산림유전자원보호구역으로 지정되어 있고, 종다양성이 높으며, 국유림지에서는 다양한 산림관리연구가 진행되고 있다. 본 연구는 1997년부터 2016년도까지 조사된 딱정벌레목을 중심으로 산림관리가 종다양성에미치는 영향을 평가하였다. 자료는 구글 스칼라, 네이버 전문정보를 통해 학술 논문 및 보고서, 국립산림과학원조사 결과 등을 통하여 얻었다. 자료에는 총 52과 473종의 딱정벌레가 기록되었으며, 반날개과와 딱정벌레과가비교적 높게 나타났다. 또한 종풍부도는 계절에 따라 큰 차이를 보여 여름에 가장 높았다. 또한 딱정벌레를 먹이섭식기능군에 따라 구분하였을 때 포식자가 상대적으로 높은 비율을 차지하였으며, 계절에 따라 기능군의 구성이 달라졌다.종다양성은 산림관리가 시행되지 않은 지역에서 가장 높게 나타나 산림관리가 딱정벌레목 종다양성에 크게 영향을미쳤다.
        36.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Data clustering determines a group of patterns using similarity measure in a dataset and is one of the most important and difficult technique in data mining. Clustering can be formally considered as a particular kind of NP-hard grouping problem. K-means algorithm which is popular and efficient, is sensitive for initialization and has the possibility to be stuck in local optimum because of hill climbing clustering method. This method is also not computationally feasible in practice, especially for large datasets and large number of clusters. Therefore, we need a robust and efficient clustering algorithm to find the global optimum (not local optimum) especially when much data is collected from many IoT (Internet of Things) devices in these days. The objective of this paper is to propose new Hybrid Simulated Annealing (HSA) which is combined simulated annealing with K-means for non-hierarchical clustering of big data. Simulated annealing (SA) is useful for diversified search in large search space and K-means is useful for converged search in predetermined search space. Our proposed method can balance the intensification and diversification to find the global optimal solution in big data clustering. The performance of HSA is validated using Iris, Wine, Glass, and Vowel UCI machine learning repository datasets comparing to previous studies by experiment and analysis. Our proposed KSAK (K-means+SA+K-means) and SAK (SA+K-means) are better than KSA(K-means+SA), SA, and K-means in our simulations. Our method has significantly improved accuracy and efficiency to find the global optimal data clustering solution for complex, real time, and costly data mining process.
        4,000원
        39.
        2017.04 구독 인증기관·개인회원 무료
        산림은 다양한 곤충에게 먹이원으로서뿐만 아니라 서식지로서 중요한 역할을 한다. 따라서 산림 벌채는 산림에 서식하는 생물들의 서식공간과 먹이자원에 영향을 주어 생물다양성이 변하게 한다. 이 연구에는 강원도 평창군 남병산일대의 낙엽송림에서 벌채 정도에 따른 나방의 다양성을 비교분석하였다. 나방조사는 유아등을 이용하여 5월부터 10월까지 매월 1회 실시하였다. 나방의 종수 및 개체수는 벌채가 되지 않은 참나무림에서 가장 높았으며, 다음으로 벌채가 되지 않은 낙엽송림에서 높았다. 개벌지 및 군상벌채지에서는 종다양성이 크게 감소하였다. 비벌채지 에서는 목본류를 섭식하는 종의 비율이 높았으며, 벌채지에서는 초본류 섭식종의 비율이 높았다. 다변량분석 결과 벌채지와 비벌채지가 명확하게 구분되었다.
        40.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Even though cars have a good effect on modern society, traffic accidents do not. There are traffic laws that define the regulations and aim to reduce accidents from happening; nevertheless, it is hard to determine all accident causes such as road and traffic conditions, and human related factors. If a traffic accident occurs, the traffic law classifies it as ‘Negligence of Safe Driving’ for cases that are not defined by specific regulations. Meanwhile, as Korea is already growing rapidly elderly population with more than 65 years, so are the number of traffic accidents caused by this group. Therefore, we studied predictive and comparative analysis of the number of traffic accidents caused by ‘Negligence of Safe Driving’ by dividing it into two groups : All-ages and Elderly. In this paper, we used empirical monthly data from 2007 to 2015 collected by TAAS (Traffic Accident Analysis System), identified the most suitable ARIMA forecasting model by using the four steps of the Box-Jenkins method : Identification, Estimation, Diagnostics, Forecasting. The results of this study indicate that ARIMA (1, 1, 0)(0, 1, 1)12 is the most suitable forecasting model in the group of All-ages; and ARIMA (0, 1, 1)(0, 1, 1)12 is the most suitable in the group of Elderly. Then, with this fitted model, we forecasted the number of traffic accidents for 2 years of both groups. There is no large fluctuation in the group of All-ages, but the group of Elderly shows a gradual increase trend. Finally, we compared two groups in terms of the forecast, suggested a countermeasure plan to reduce traffic accidents for both groups
        4,600원
        1 2 3 4 5