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        검색결과 1,056

        21.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Taguchi method is one of the most popular approaches for design optimization such that performance characteristics become robust to uncontrollable noise variables. However, most previous Taguchi method applications have addressed a single-characteristic problem. Problems with multiple characteristics are more common in practice. The multi-criteria decision making(MCDM) problem is to select the optimal one among multiple alternatives by integrating a number of criteria that may conflict with each other. Representative MCDM methods include TOPSIS(Technique for Order of Preference by Similarity to Ideal Solution), GRA(Grey Relational Analysis), PCA(Principal Component Analysis), fuzzy logic system, and so on. Therefore, numerous approaches have been conducted to deal with the multi-characteristic design problem by combining original Taguchi method and MCDM methods. In the MCDM problem, multiple criteria generally have different measurement units, which means that there may be a large difference in the physical value of the criteria and ultimately makes it difficult to integrate the measurements for the criteria. Therefore, the normalization technique is usually utilized to convert different units of criteria into one identical unit. There are four normalization techniques commonly used in MCDM problems, including vector normalization, linear scale transformation( max-min, max, or sum). However, the normalization techniques have several shortcomings and do not adequately incorporate the practical matters. For example, if certain alternative has maximum value of data for certain criterion, this alternative is considered as the solution in original process. However, if the maximum value of data does not satisfy the required degree of fulfillment of designer or customer, the alternative may not be considered as the solution. To solve this problem, this paper employs the desirability function that has been proposed in our previous research. The desirability function uses upper limit and lower limit in normalization process. The threshold points for establishing upper or lower limits let us know what degree of fulfillment of designer or customer is. This paper proposes a new design optimization technique for multi-characteristic design problem by integrating the Taguchi method and our desirability functions. Finally, the proposed technique is able to obtain the optimal solution that is robust to multi-characteristic performances.
        4,000원
        22.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Species distribution model (SDM) is used to preserve biodiversity and climate change impact. To evaluate biodiversity, various studies are being conducted to utilize and apply SDM. However, there is insufficient research to provide useful information by identifying the current status and recent trends of SDM research and discussing implications for future research. This study analyzed the trends and flow of academic papers, in the use of SDM, published in academic journals in South Korea and provides basic information that can be used for related research in the future. The current state and trends of SDM research were presented using philological methods and text-mining. The papers on SDM have been published 148 times between 1998 and 2023 with 115 (77.7%) papers published since 2015. MaxEnt model was the most widely used, and plant was the main target species. Most of the publications were related to species distribution and evaluation, and climate change. In text mining, the term ‘Climate change’ emerged as the most frequent keyword and most studies seem to consider biodiversity changes caused by climate change as a topic. In the future, the use of SDM requires several considerations such as selecting the models that are most suitable for various conditions, ensemble models, development of quantitative input variables, and improving the collection system of field survey data. Promoting these methods could help SDM serve as valuable scientific tools for addressing national policy issues like biodiversity conservation and climate change.
        4,600원
        23.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        대량유살 기술을 통한 총채벌레 방제 기술이 시설 고추재배지를 중심으로 개발되었다. 이 기술의 핵심 요인은 효과적 유인제 개발에 있다. 집합페로몬에 의존하였던 유인전략은 노지 재배지에서는 뚜렷한 효과를 보이지 않았다. 따라서 본 연구는 노지 고추재배지에서 총채벌레의 대량 유살을 위해 새로운 유인물질의 추가가 필요하였다. 또한 노지재배지에서 집합페로몬의 유인력 감소 원인을 규명할 필요가 있었다. 새로운 유인 물질로서 methyl isonicotinate (MIN)이 제시되었고, 이 물질이 실내 유인행동분석을 통해 총채벌레에 대한 자체 유인력은 물론이고 집합페로 몬과 협력효과를 보였다. 이를 바탕으로 집합페로몬과 혼합물 형태로 노지 고추재배지에서 분석한 결과 총채벌레의 포획밀도를 증가시켰다. 특 히 이러한 증가는 꽃노랑총채벌레(Frankliniella occidentalis)에서 뚜렷하게 나타났다. 유인트랩에 집합페로몬의 함량 증가는 노지 고추재배지에 서 꽃노랑총채벌레는 물론이고 다른 총채벌레류의 포획밀도를 뚜렷하게 증가시켰다. 본 연구는 집합페로몬 유인력이 시설재배지와 노지재배지 사이에서 차이가 있으며, 노지 재배지의 경우 효과적 유인력을 발휘하기 위해서는 더욱 많은 집합페로몬 함량을 요구한다는 것을 밝혔다. 또한 본 연구는 집합페로몬에 MIN을 추가하여 꽃노랑총채벌레에 대한 고효율 유인제를 개발할 수 있는 기술을 제시한다.
        4,000원
        24.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the AHP (analytic hierarchy process) technique was used to analyze the risk of expected risk factors and fishing possibilities during gillnet fishing within the floating offshore wind farms (floating OWF). For this purpose, the risks that may occur during gillnet fishing within the floating offshore wind farms were defined as collisions, entanglements, and snags. In addition, the risk factors that cause these risks were classified into three upper risk factors and ten sub risk factors, and the three alternatives to gillnet fishing available within the floating OWF were classified and a hierarchy was established. Lastly, a survey was conducted targeting fisheries and marine experts and the response results were analyzed. As a result of the analysis, among the top risk factors, the risk was the greatest when laying fishing gear. The risk of the sub factors for each upper risk was found to be the highest at the berthing (mooring), the final hauling of fishing net, and the laying of the bottom layer net. Based on the alternatives, the average of the integrated risk rankings showed that allowing full navigation/fisheries had the highest risk. As a result of the final ranking analysis of the integrated risk, the overall ranking of allowing navigation/fisheries in areas where bottom layer nets were laid was ranked the first when moving vessels within the floating OWF was analyzed as the lowest integrated risk ranking of the 30th at the ban on navigation/fisheries. Through this, navigation was analyzed to be possible while it was analyzed that the possibility of gillnet fishing within the floating OWF was not high.
        4,000원
        30.
        2023.11 구독 인증기관·개인회원 무료
        Wolsong Unit 1, a domestic heavy water reactor nuclear power plant, was permanently shut down in December 2019. Accordingly, Wolsong Unit 1 plans to prepare a Final Decommissioning Plan (FDP), submit it to the government by 2024, receive approval for decommissioning, and begin full-scale decommissioning. One of the important tasks in the decommissioning of Wolsong Unit 1 is to determine the decommissioning strategy. It is necessary to decide on a decommissioning strategy considering various factors and variables, secure the technical background, and justify it. The selection of a decommissioning strategy is best achieved through the use of formal decisionmaking assistance techniques, such as considerations related to influencing factors. It is very important to understand the basic decommissioning strategy alternatives and whether sufficient consideration has been given to situations where only a single unit is permanently shut down in a multi-unit site like Wolsong Unit 1, while the remaining units are in normal operation. As a process for selecting a decommissioning strategy, first, all considerations that could potentially affect decommissioning presented in the KINS Decommissioning Safety Review Guidelines were synthesized, influencing factors to be used in the decision-making process were determined, and the concept was defined. In order to select the most appropriate decommissioning strategy by considering various evaluation attributes of possible decommissioning alternatives (immediate dismantling and delayed dismantling), the Wolsong Unit 1 decommissioning strategy was evaluated by reflecting the AHP decision-making technique.
        31.
        2023.11 구독 인증기관·개인회원 무료
        Domestic commercial low- and intermediate-level radioactive waste storage containers are manufactured using 1.2 mm thick cold-rolled steel sheets, and the outer surface is coated with a thin layer of primer of 10~36 μm. However, the outer surface of the primer of the container may be damaged due to physical friction, such as acceleration, resonance, and vibration during transportation. As a result, exposed steel surfaces undergo accelerated corrosion, reducing the overall durability of the container. The integrity of storage containers is directly related to the safety of workers. Therefore, the development of storage containers with enhanced durability is necessary. This paper provides an analysis of mechanical properties related to the durability of WC (tungsten carbide)-based coating materials for developing low- and intermediate-level radioactive waste storage containers. Three different WC-based coating specimens with varied composition ratios were prepared using HVOF (high-velocity oxy-fuel) technique. These different specimens (namely WC-85, WC-73, and WC-66) were uniformly deposited on cold-rolled steel surfaces ensuring a constant thickness of 250 μm. In this work, the mechanical properties of the three different WCbased coaitng materials evaluated from the viewpoints of microstructure, hardness, adheision force between substrate and coating material, and wear resistance. The cross-sectional SEM-EDS (Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy) images revealed that elements W (tungsten), C (carbon), Ni (nickel), and Cr (chromium) were uniformly distributed within the each coating layers which was approximately 250 μm thick. The average hardness values of HWC-85 and HWC-73 were found to be 1,091 Hv (Vickers Hardness) and 1,083 Hv, respectively, while the HWC-66 exhibited relatively lower hardness value of 883 Hv. This indicates that a higher WC content results in increased hardness. Adhesion force between and substrates and coating materials exceeded 60 MPa for all specimens, however, there were no significant differences observed based on the tungsten carbide content. Furthermore, a taber-type abrasion tester was used for conducting abrasion resistance tests under specific conditions including an H-18 load weight at 1,000 g with rotational speed set at 60 RPM. The abrasion resistance tests were performed under ambient temperatures (RT: 23±2°C) as well as relative humidity levels (RH: 50±10%). Currently, the ongoing abrasion resistance tests will include some results in this study.
        34.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Proprioception in the ankle joint is important for maintaining balance. There is a correlation between joint position sense (JPS), balance and ankle dorsiflexion range of motion (DF-ROM). Objectives: The purpose of this study was to compare the effects of talocrural joint mobilization (TJM) and muscle energy technique (MET) of plantar flexor muscle (PF) on improving joint position sense (JPS) and static balance. Design: Cross-over randomized trial research. Methods: Sixteen participants (male 10, female 6; 20’s of their age) without ankle instability were recruited. In a randomized, three conditions, no intervention, talocalcaneal mobilization, and PF-MET were all applied to 16 participants. For TJM, the Kaltenborn grade 3 joint gliding method, in which the talus moves posteriorly perpendicular to the tacrocrural joint plane, were used. In the PF-MET, MET method were applied gastrocnemius muscle and soleus muscle with 25% of 1 Repeat Maximum of each muscle. The all participants performed PF-MET and TJM for 18 minutes. DF-ROM measured the weightbearing lunge test. JPS measured using the active joint angle reproduction test. Static balance was measured displacement of center of pressure parameter. Results: PF-MET and TJM had significant differences in DF-ROM and AP displacements. PF-MET significantly increased at 5° and 15° of plantar flexion and 5° of dorsiflexion, and COP velocity significantly decreased in JPS compared to TJM. Conclusion: PF-MET and TJM are effective in increasing DF-ROM. However, PF-MET has a more positive effect on improving JPS and static balance than on talocrural joint mobilization.
        4,000원
        35.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The metal bush assembling process is a process of inserting and compressing a metal bush that serves to reduce the occurrence of noise and stable compression in the rotating section. In the metal bush assembly process, the head diameter defect and placement defect of the metal bush occur due to metal bush omission, non-pressing, and poor press-fitting. Among these causes of defects, it is intended to prevent defects due to omission of the metal bush by using signals from sensors attached to the facility. In particular, a metal bush omission is predicted through various data mining techniques using left load cell value, right load cell value, current, and voltage as independent variables. In the case of metal bush omission defect, it is difficult to get defect data, resulting in data imbalance. Data imbalance refers to a case where there is a large difference in the number of data belonging to each class, which can be a problem when performing classification prediction. In order to solve the problem caused by data imbalance, oversampling and composite sampling techniques were applied in this study. In addition, simulated annealing was applied for optimization of parameters related to sampling and hyper-parameters of data mining techniques used for bush omission prediction. In this study, the metal bush omission was predicted using the actual data of M manufacturing company, and the classification performance was examined. All applied techniques showed excellent results, and in particular, the proposed methods, the method of mixing Random Forest and SA, and the method of mixing MLP and SA, showed better results.
        4,000원
        36.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        With the recent advent of Metaverse, the character industry that reflects the characteristics of users' faces is drawing attention. there is a hassle that users have to select face components such as eyes, nose, and mouth one by one. In this paper, we propose a diffusion-based model that automatically generates characters from content human photographs. Our model generates user artistic characters by reflecting content information such as face angle, direction, and shape of a content human photo. In particular, our model automatically analyzes detailed information such as glasses and whiskers from content photo images and reflects them in artistic characters generated. Our network generates the final character through a three-step: diffusion process, UNet, and denoising processes. We use image encoders and CLIP encoders for the connection between style and input data. In the diffusion process, a collection of noise vectors is gradually added to a style vector to enable lossless learning of the detailed styles. All input values except for the style images are vectorized with CLIP encoders and then learned with noise style vectors in the UNet. Subsequently, noise is removed from the vectors through the UNet to obtain the artistic character image. We demonstrate our performance by comparing the results of other models with our results. Our method reflects content information without loss and generates natural high-definition characters.
        4,000원
        37.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        With the increasing number of aging buildings across Korea, emerging maintenance technologies have surged. One such technology is the non-contact detection of concrete cracks via thermal images. This study aims to develop a technique that can accurately predict the depth of a crack by analyzing the temperature difference between the crack part and the normal part in the thermal image of the concrete. The research obtained temperature data through thermal imaging experiments and constructed a big data set including outdoor variables such as air temperature, illumination, and humidity that can influence temperature differences. Based on the collected data, the team designed an algorithm for learning and predicting the crack depth using machine learning. Initially, standardized crack specimens were used in experiments, and the big data was updated by specimens similar to actual cracks. Finally, a crack depth prediction technology was implemented using five regression analysis algorithms for approximately 24,000 data points. To confirm the practicality of the development technique, crack simulators with various shapes were added to the study.
        4,000원
        38.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        치유농업의 목적은 건강회복 및 유지, 증진을 위한 사회적 비용의 절감과 농촌의 활력, 소득원의 창출을 통한 농업‧농촌의 지속가능한 성장에 있다. 이러한 치유농업의 가치는 치유농업 대상자뿐만 아니라 농 업인, 지역사회, 보건서비스 제공자 등 다양한 주체가 혜택을 얻는 데 있다. 이 연구는 치유농업의 지속 가능한 생태계 구축방안을 제시하고자 선행연구를 통해 핵심요인을 도출하여 환경생태적, 사회경제 적 편익, 지역사회발전으로 설정하였다. 또한 각각의 요인은 하위요인으로 구분하여 적합도와 중요도 를 파악하였다. 델파이 조사는 치유농업에 실무와 경험이 풍부한 연구자, 교수, 치유농가 등 전문가 15 명을 대상으로 하였는데 이 중 불성실한 답변을 제외하고 최종 12명을 대상으로 2차에 걸친 조사를 하 였다. 분석결과 치유농업의 지속가능한 생태계 구축을 위한 핵심요인을 도출하였다. 또한 측정영역과 하위요인에 대한 중요도와 적합도 분석결과 7개의 상위요인과 33개 하위요인을 선정하였다. 지역사회 의 다양한 주체와의 교류 활성화를 통해 농업, 의료, 사회, 교육 분야에서 농업의 새로운 대안으로써 치 유농업을 운영할 필요가 있다. 이를 통해 치유농업의 지속가능한 생태계 구축을 위한 정책지원과 기초 적인 방향성을 제시하였다는 점에서 의미가 있다.
        4,000원
        39.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 현재 가설되어 가용 중인 프리스트레스트 구조물에 대해서 긴장 응력을 계측하는 방법에 관한 연구를 위해 외부 자화를 이용한 PSC 텐던의 긴장 응력 계측에 관한 연구를 진행하였다. 이에 유한요소해석을 이용하여 PSC 거더에 외부 자화 시 잔존 긴장 응 력을 검출하기 위해 PSC 거더 내부의 PS 텐던까지 영향을 줄 수 있는 코일 배치 및 크기 등을 고려하여 최적의 센서를 설계하였다. 또 한, 유한요소해석을 이용하여 설계한 센서와 동일한 수치 및 재질 데이터를 이용해 이론적 검증을 진행하였으며 타겟 위치에서 자화 의 세기를 계산하였을 때, 유한요소해석 결과와 동일한 결과를 얻어낼 수 있었다. 이를 통해 설계한 센서의 검증 및 비 접촉 외부 자화 EM 센서를 활용하여 PSC I형 거더 내부 텐던의 자화가 가능함을 확인하였다.
        4,000원
        40.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the physical properties and fracture characteristics according to the tensile load are evaluated on the materials of the polymeric filler and carbon fiber-based composite sleeve technique. The polymeric filler and the composite sleeve technique are applied to areas where the pipe body thickness is reduced due to corrosion in large-diameter water pipes. First, the tensile strength of the polymeric filler was 161.48~240.43 kgf/cm2, and the tensile strength of the polyurea polymeric filler was relatively higher than that of the epoxy. However, the tensile strength of the polymeric filler is relatively very low compared to ductile cast iron pipes(4,300 kgf/cm2<) or steel pipes(4,100 kgf/cm2). Second, the tensile strength of glass fiber, which is mainly used in composite sleeves, is 3,887.0 kgf/cm2, and that of carbon fiber is up to 5,922.5 kgf/cm2. The tensile strengths of glass and carbon fiber are higher than ductile cast iron pipe or steel pipe. Third, when reinforcing the hemispherical simulated corrosion shape of the ductile cast iron pipe and the steel pipe with a polymeric filler, there was an effect of increasing the ultimate tensile load by 1.04 to 1.06 times, but the ultimate load was 37.7 to 53.7% compared to the ductile cast iron or steel specimen without corrosion damage. It was found that the effect on the reinforcement of the corrosion damaged part was insignificant. Fourth, the composite sleeve using carbon fiber showed an ultimate load of 1.10(0.61T, 1,821.0 kgf) and 1.02(0.60T, 2,290.7 kgf) times higher than the ductile cast iron pipe(1,657.83 kgf) and steel pipe(2,236.8 kgf), respectively. When using a composite sleeve such as fiber, the corrosion damage part of large-diameter water pipes can be reinforced with same level as the original pipe, and the supply stability can be secured through accident prevention.
        4,300원
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