• Korean Journal of Agricultural Science
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• v.48 no.4
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• pp.1027-1037
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• 2021

This study aims to evaluate the performance of an electric multi-purpose cultivator through a simulation analysis. The simulation model was developed using commercial software, Simulation X, by applying the specifications of certain parts, such as an electric motor, a battery, and so on. The input parameter of the simulation was the engine load data according to the rotary tillage level using a conventional multi-purpose cultivator. The data were collected by configuring a load measurement system, and the load cycle was developed by repeating the data collection process under the most severe conditions. The average output engine torque values of conventional multi-purpose cultivator were 10.7, 13.0, 9.4, and 11.2 Nm in the D1P1, D1P2, D2P1, and D2P2 conditions, respectively. As a result of the simulation, the maximum values of the motor torque, rotational speed, and power of the electric multi-purpose cultivator were 16.8 Nm, 2,033.3 rpm, and 3.3 kW, respectively, and the motor was driven in sections within 70, 68, and 45% of the maximum output range. The rate of decrease of the battery state of charge (SOC) level per minute was approximately 0.6%, and it was possible to supply electric power to the motor for 9,550 sec. In the future study, research to verify and improve simulation models of electric multi-purpose cultivators should be conducted.

• The Journal of the Acoustical Society of Korea
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• v.41 no.2
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• pp.210-217
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• 2022

Passive source depth estimation has been studied for decades since the source depth can be used for target classification, target tracking, etc. The purpose of this paper is to solve the problem of ambiguity in the previous paper [S.-il. Cho et al. (in Korean), J. Acoust. Soc. Kr. 38, 120-127 (2019)] that source depth is estimated in two points. The patterns of phase shift of Channel Impulse Response(CIR) reflected in ocean surface and bottom is used for removing ambiguity of the source depth estimation, and after removing ambiguity, source depth is estimated at one point through the intersection of CIR. In order to extract CIR in case of unknown source signal and continuous signal or noise, Ray-based blind deconvolution is used. The proposed algorithm is demonstrated through numerical simulation in ocean waveguide.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.74-74
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• 2020

싱가포르의 물분야는 선도적 글로벌 하이드로허브(Global hydrohub)로, 글로벌 물시장에서 싱가포르의 위상을 견고하게 하면서, 지속적으로 괄목할만한 성장세를 이어가고 있다. 200개 이상의 물관련 기업, 25개 이상의 연구소와 더불어, 싱가포르 물분야는 2018년까지 25억 싱가포르달러의 부가가치 창출과 14,400개의 일자리를 창출하면서, 세계 각국으로부터 투자를 유치하고 있다. 또한, 싱가포르는 2006년 이래 국립연구재단(National Research Fund: NRF)에 6억 7천만 싱가포르 달러만큼 기금을 누적하여 2020년에는 28억 싱가포르달러의 부가가치 창출과 15,000개 일자리 창출이라는 목표를 달성 할 수 있을 것으로 예상된다. 이와 더불어 연구, 혁신 및 기업 (Research, Innovation, and Enterprise: RIE) 2020 계획을 달성하기 위하여, 싱가포르 국가 물기관인 PUB, 경제개발이사회(Economic Development Board: EDB) 및 기업싱가포르(Enterprise Singapore)는 싱가포르의 물분야 강점을 활용하여 다음과 같은 세 가지 분야에 초점을 맞추고 있다. 즉 1)"글로벌 국가가 요구하는 솔루션 개발", 2)"기술의 상업화(commercialization)"와 수출"을 가속화하고 3)"다양한 역량과 재능을 육성"하는 것이다. 본 연구는 싱가포르 PUB의 자국 물기업 지원을 위한 전략사례를 분석함으로써 한국 물분야 SOC공공기관의 인프라 건설 및 운영 노하우를 활용한 물분야 부가가치 창출 및 일자리 확대를 통해 현(現)정부의 경제정책 기조인 물분야에 대한 혁신성장과 일자리 창출 방안 마련에 기여하고자 한다. 또한, 본 연구를 통해 물분야 대표적 성공사례인 싱가포르 물분야 공공기관의 운영정책과 PUB의 경영전략을 분석하여, 국내 물기업의 해외진출 활성화를 위한 지원전략 수립의 기초자료를 제공하고자 한다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6D
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• pp.703-709
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• 2009

This article analyzes the obtained data on consciousness survey of disabled and non-disabled pedestrians, and proposes fundamental data for public strategy in order to enhance facilities in subway stations in advance. This paper conduct literature review, new listing survey related to 'The Code for Improvement of Convenience for Moving Vulnerable Pedestrians', and Modified-Importance-Performance Analysis (M-IPA). The results show that disabled pedestrians want enhancement in information facilities as a whole. In addition, the results show that several improvements needs to be applied to accessible sidewalk, to informative notification, to alarm and evacuation system and to toilet for disabled pedestrians. This indicates that disabled pedestrians heavily concentrate on accessibility to subway station and provided information compared with disabled pedestrians.

• Journal of Information Science Theory and Practice
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• v.10 no.spc
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• pp.143-153
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• 2022

With the development of networks and the increase in the number of network devices, the number of cyber attacks targeting them is also increasing. Since these cyber-attacks aim to steal important information and destroy systems, it is necessary to minimize social and economic damage through early detection and rapid response. Many studies using machine learning (ML) and artificial intelligence (AI) have been conducted, among which payload learning is one of the most intuitive and effective methods to detect malicious behavior. In this study, we propose a preprocessing method to maximize the performance of the model when learning the payload in term units. The proposed method constructs a high-quality learning data set by eliminating unnecessary noise (stopwords) and preserving important features in consideration of the machine language and natural language characteristics of the packet payload. Our method consists of three steps: Preserving significant special characters, Generating a stopword list, and Class label refinement. By processing packets of various and complex structures based on these three processes, it is possible to make high-quality training data that can be helpful to build high-performance ML/AI models for security monitoring. We prove the effectiveness of the proposed method by comparing the performance of the AI model to which the proposed method is applied and not. Forthermore, by evaluating the performance of the AI model applied proposed method in the real-world Security Operating Center (SOC) environment with live network traffic, we demonstrate the applicability of the our method to the real environment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5D
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• pp.723-730
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• 2006

Recently, The flexible moving block system in train operation has been introduced to the worldwide rail transportation markets. This paper is a comparative study of the conventional fixed block systems effects and the flexible moving block system on train operating time saving. Based on the literature review, the new algorithm is developed. It is to calculate the optimum headway time of the train. The proposed algorithm can overcome some of the existing algorithm problems, such as the limits of the data and unaware of the rail characteristic. The total travel time saving effect has been analyzed by applying the skip stop scheduling system to the each block system. The results of this study indicated that the total travel time is approximately 40% decreased and the schedule velocity is approximately 24% improved when the moving block system is applied. The results of this study could be used as a theoretical basis for the selection of rail signal system in Seoul's subway number 2 line.

• The Journal of Sustainable Design and Educational Environment Research
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• v.22 no.3
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• pp.14-29
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• 2023

This study aims to elucidate the content and format of school safety standards to clarify the roles and responsibilities of schools in realizing school safety. Toward this end, difficulties in operating school safety standards at various sites were classified into four small groups with a total of 26 educational administrators, superintendents, and researchers to listen to the opinions of experts in the field and analyze related data. As a result, we comprehensively analyzed in-depth interviews with the respondents who are working at provincial offices of education regarding the proposed school safety standards. We also analyzed the necessity of developing these standards and examining the appropriateness of their content and format. Results were derived from four aspects, including the field applicability of such standards. The study draws the following conclusions. First, it focuses on setting the direction for the development of school safety standards. Second, it highlights the exploration of the system and content of these standards. Third, it pertains to the preparation of a draft of these standards.

• Journal of Korean Society of Rural Planning
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• v.29 no.4
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• pp.81-92
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• 2023

The purpose of this study is to identify rural research topics, differences in research topics over time, and key mediators through the analysis of academic research trends using topic modeling. This study analyzed a total of 1,183 articles published in the Journal of Rural Planning and Rural Society over a 23-year period (2000-2022). We categorized rural research topics into 30, examined the proportion of research in each topic, and identified major changes in research topics over time. We also identified key words that mediate between research topics. The study found that, first, rural research trends can be categorized into five types (resources and utilization, area/space, people, ecosystem/environment, and tourism), with area/space being the most studied. Subtopics include rural amenities, rural disappearance/village miniaturization, and rural landscape management. Second, the research topics for each period were different. In the first period(2003-2007), the main research topics were rural amenities and Agricultural production- based climate vulnerability assessment. In the second period(2008-2012), the main research topics were Rural extinction and village depopulation, and rural landscape management, and in the third period(2013-2017), the main research topics were rural sixth industrialization and rural ecotourism. In the fourth period(2018-2022), rural development planning and rural life services(life SOC) were the main research topics. The significance of this study is that it extends the existing method of analyzing research trends and provides basic data to enhance comprehensive insights and understanding of rural research.

• Informatization Policy
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• v.30 no.3
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• pp.69-91
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• 2023

The impact of technological advancements on employment is a matter of ongoing debate, with discussions on the effects of AI technology development on employment being particularly scarce. This study employs the natural language processing technique (SBERT) and patents to calculate an occupation-based AI exposure score and to analyze employment trends by group. It proposes a method for calculating the AI exposure score based on the similarity between Korean patent information and US job descriptions and linking SOC(U.S.) and KSCO(Korea). The analysis of domestic AI patent applications and regional employment data in the KOSIS Database since 2013 reveals a K-shaped polarization pattern in Korean employment trends among groups with above and below average levels of AI exposure.

• The Journal of the Acoustical Society of Korea
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• v.25 no.7
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• pp.339-345
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• 2006

We suggest new 2D two-way Parabolic equation algorithm for multiple scattering. Our method is based on the successive performance of the single scattering approach. First. as the single scattering algorithm, the reflected and transmitted fields are calculated at the vertical interface of a range independent sector. Then. the reflected field is saved and the transmitted field Propagated to the next vertical interface with the split-step Pade method. After one step ends, the same Process is repeatedly performed with the change of the Propagation direction until the reflected field at the vertical interface is close to zero. Final incoming and outgoing fields are obtained as the sum of the wave fields obtained for each step. Our algorithm is relatively simple for the numerical implementation and requires less computational resources than the existing algorithm for multiple scattering