• Journal of Korean Society of Rural Planning
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• v.25 no.3
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• pp.77-87
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• 2019

This study is to identify the factors affecting commuting time and modes in urban and rural areas using household traffic survey data. The findings indicated that commuting time using passenger car in rural areas was 1.6 times longer than those in urban areas. When citizen use public transportation, however, there was not much difference in commuting time in urban and rural areas. Among the various factors affecting commuting time in rural areas (13 factors have statistical significance), the most influential factors were that public transportation, managers and office workers, functional and device managers, and passenger car. In urban areas, the highly influential factors were public transportation and walking among the 16 affecting factors which have statistical significance. The commuting time in rural areas increased according to the occupation types, but the commuting time of full-time workers decreased. This phenomenom means that occupation groups with the full-time system prefer residential areas in the densely populated town.

• Journal of the Korea Society of Computer and Information
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• v.26 no.8
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• pp.47-54
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• 2021

Given a document, keyphrase extraction is to automatically extract words or phrases which topically represent the content of the document. In unsupervised keyphrase extraction approaches, candidate words or phrases are first extracted from the input document, and scores are calculated for keyphrase candidates, and final keyphrases are selected based on the scores. Regarding the computation of the scores of candidates in unsupervised keyphrase extraction, this study proposes a method of adjusting the scores of keyphrase candidates according to the types of keyphrase candidates: word-type or phrase-type. For this, type-token ratios of word-type and phrase-type candidates as well as information content of high-frequency word-type and phrase-type candidates are collected from the input document, and those values are employed in adjusting the scores of keyphrase candidates. In experiments using four keyphrase extraction evaluation datasets which were constructed for full-text articles in English, the proposed method performed better than a baseline method and comparison methods in three datasets.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.1
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• pp.26-32
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• 2022

This paper proposes a power system that includes a 120k W fuel cell DC-DC converter (FDC) and 30 kW bidirectional DC-DC converter (BHDC) for a 150 kW fuel-cell vehicle. With a high DC link voltage of 800 V, the efficiency and power density of the power electronic components are improved. Through the modular design of FDC and BHDC, electric components are shared, resulting in reduced mass production costs. The switching frequency of 30 kHz of full SiC devices and optimal design of coupled inductor reduce the volume, achieving a power density of 8.3 kW/L. Furthermore, a synergetic operation strategy using variable limiter control of FDC and BHDC was proposed to efficiently operate the fuel cell vehicle considering the fuel cell stack efficiency according to the load. Finally, the performance of the prototype was verified by Highway Fuel Economy Driving Schedule testing, EMI test, and the linked operation between FDC and BHDC. The full load efficiencies of the FDC and BHDC prototypes are 98.47% and 98.74%, respectively.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.11 no.3
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• pp.171-177
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• 2011

The decision making process is based on accurate and timely available information. To obtain precise information from the internet is becoming more difficult due to the continuous increase in vagueness and uncertainty from online information resources. This also poses a problem for blind people who desire the full use from online resources available to other users for decision making in their daily life. Ontology is considered as one of the emerging technology of knowledge representation and information sharing today. Fuzzy logic is a very popular technique of artificial intelligence which deals with imprecision and uncertainty. The classical ontology can deal ideally with crisp data but cannot give sufficient support to handle the imprecise data or information. In this paper, we incorporate fuzzy logic with heavyweight ontology to solve the imprecise information extraction problem from heterogeneous misty sources. Fuzzy ontology consists of fuzzy rules, fuzzy classes and their properties with axioms. We use Fuzzy OWL plug-in of Protege to model the fuzzy ontology. A prototype is developed which is based on OWL-2 (Web Ontology Language-2), PAL (Protege Axiom Language), and fuzzy logic in order to examine the effectiveness of the proposed system.

• Journal of Korean Library and Information Science Society
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• v.33 no.4
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• pp.1-18
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• 2002

Library and information science(LIS) has been focused on the issues of information poverty and barriers and their relations, mainly in terms of current information users. However, potential users usually out of sight in library and information services undoubtedly are to be developed as legitimate clientele. In this regard, this paper attempts to shed light on some factors related to the methodological underpinnings of LIS. Ethnographic research is particularly highlighted. Since the mid 1980s, as full-fledged research of analyzing the contingencies of information use as situated in particular times and places. md using that analysis to inform user-centered information systems design LIS researchers and practitioners have been exploring possible use of ethnographic approaches, especially in studies investigating information world of the socially marginalized. This Paper addresses issues in conducting ethnographic studies in the discipline. This paper also discusses the experiences in conducting ethnographic based research md how the results of their studies may be or have been useful in improving information services fir specific populations.

• Journal of Korean Library and Information Science Society
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• v.39 no.2
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• pp.39-63
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• 2008

The purpose of this study Is to Investigate unique features in the everyday information behavior of Korean Americans, in particular, the sub-group residing in the Mid-west area such as Ohio, Kentucky, and Indiana. Major focus was on undercovering the impacts of ethnic identity and residential environment on their information behavior. The data for discussion were mainly collected by a full-scale survey and in-depth interviews. In Conclusion, suggested is the promotion of information welfare policies that are appropriate for the various and complicate information behaviors of ethnic minority groups(such as Korean Americans).

• Journal of KIBIM
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• v.13 no.4
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• pp.74-84
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• 2023

Modern construction projects have stakeholders from various construction fields, highlighting the importance of efficient information sharing and collaboration. The expanding scope of Building Information Modeling (BIM), particularly in the domestic construction sector, necessitates a Common Data Environment (CDE). However, applying foreign commercial CDE solutions within the domestic context is challenging due to the difficulty of aligning them with the unique organizational structures and characteristics prevalent in the country. Furthermore, the information review and approval processes specified by ISO 19650 often fail to harmonize adequately with the domestic design procedures, limiting the full utilization of CDE advantages. This study endeavors to develop a Korean CDE collaborative platform based on ISO 19650, with a focus on adapting workflows and information container systems to the domestic context. Building upon the requirements of ISO 19650-based CDE workflows and information containers, this research involves an in-depth analysis of information generation, sharing, review, and approval processes within domestic design organizations, offering tailored CDE workflows and information container systems that align with the specific needs of the Korean construction industry.

• Journal of the Korean Institute of Gas
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• v.9 no.4 s.29
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• pp.57-61
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• 2005

The objective of paper is to carry out a comparative Quantitative Risk Assessment (QRA) of two KOGAS tank designs using a fault tree methodology, a standard 'Full Containment' tank and a 'Membrane' tank. For the membrane tank, both the initial KOGAS design and 4 modified KOGAS designs have been assessed, giving six separate cases. In this paper, the frequencies of releases are quantified using a fault tree approach. For clarity in the analysis, and to ensure consistency, all cases have been quantified using the same fault tree. Logic within the fault tree is used to select each of the cases. Full quantification of risks is often difficult, owing to a lack of relevant failure data, but the aim of this study has been to be as quantitative as possible, with full transparency of failure information. The most significant general cause of external LNG leaks is predicted to be a seismic event, which has been quantified nominally. 4modified KOGAS desiens to Prevent damage of bottom membrane panels that was shown in preparatory estimation could quantitively confirm safety improvement. According to result, the predicted frequencies of an external LNG leak for the full containment and modified membrane tanks are very similar, failures due to dropped pumps are predicted to be significantly greater for the membrane tank with thickened plate than for the full containment tank.

• Journal of Internet Computing and Services
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• v.21 no.1
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• pp.179-190
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• 2020

In the Unix-like system environment, the GOT overwrite attack is one of the traditional control flow hijacking techniques for exploiting software privileges. Several techniques have been proposed to defend against the GOT overwrite attack, and among them, the Full Relro(Relocation Read only) technique, which blocks GOT overwrites at runtime by arranging the GOT section as read-only in the program startup, has been known as the most effective defense technique. However, it entails loading delay, which limits its application to a program sensitive to startup performance, and it is not currently applied to the library due to problems including a chain loading delay problem caused by nested library dependency. Also, many compilers, including LLVM, do not apply the Full Relro technique by default, so runtime programs are still vulnerable to GOT attacks. In this paper, we propose a GOT protection scheme using the Control Flow Integrity(CFI) technique, which is currently recognized as the most suitable technique for defense against code reuse attacks. We implemented this scheme based on LLVM and applied it to the binutils-gdb program group to evaluate security, performance and compatibility. The GOT protection scheme with CFI is difficult to bypass, fast, and compatible with existing library programs.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.5
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• pp.388-396
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• 2003

In this paper, a fast motion search algorithm that performs motion search for variable blocks in integer pixel unit is proposed. The proposed method is based on the successive elimination algorithm (SEA) using sum norms to find the best estimate of motion vector and obtains the best estimate of the motion vectors of blocks, including 16${\times}$8, 8${\times}$16, and 8${\times}$8, by searching eight pixels around the best motion vector of 16${\times}$16 block obtained from all candidates. And the motion vectors of blocks, including 8${\times}$4, 4${\times}$8, and 4${\times}$4, is obtained by searching eight pixels around the best motion vector of 8${\times}$8 block. The proposed motion search is applied to the H.264 encoder that performs variable blocks motion estimation (ME). In terms of computational complexity, the proposed search algorithm for motion estimation (ME) calculates motion vectors in about 23.8 times speed compared with the spiral full search without early termination and 4.6 times speed compared with the motion estimation method using hierarchical sum of absolute difference (SAD) of 4${\times}$4 blocks, while it shows 0.1dB∼0.4dB peak signal-to-noise ratio (PSNR) drop in comparison to the spiral full search.