• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3421-3425
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• 2015

In sensor networks, sensor nodes are usually distributed to manage the networks in continuous unique area, however as by the network property nodes can be located in several areas. The data gathering of distributed nodes to several areas can be different with current continuous area. Hence, the distributed networks can be differently managed to the current continuous networks. In this paper, we describe the data gathering of sensor nodes in distributed sensor areas. It is possible that sensor nodes cannot instantly connect the mobile sink, and the node operation should be considered. The real time data sending to the instant connection scheme of mobile sink can be implemented, but the property of mobile sink should be considered for the sink connection of distributed areas. In this paper, we analyze the proposed scheme by the simulation results. The simulation results show that the overall lifetime to the periodic data gathering method is longer than the threshold method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.7
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• pp.3412-3432
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• 2019

Recent advances in radio frequency (RF) power transfer provide a promising technology to power sensor nodes. Adoption of mobile chargers to replenish the nodes' energy has recently attracted a lot of attention and the mobility assisted energy replenishment provides predictable and sustained power service. In this paper, we study the joint optimization of mobile charging and data gathering in sensor networks. A wireless multi-functional vehicle (WMV) is employed and periodically moves along specified trajectories, charge the sensors and gather the sensed data via one-hop communication. The objective of this paper is to maximize the uplink throughput by optimally allocating the time for the downlink wireless energy transfer by the WMV and the uplink transmissions of different sensors. We consider two scenarios where the WMV moves in a straight line and around a circle. By time discretization, the optimization problem is formulated as a 0-1 programming problem. We obtain the upper and lower bounds of the problem by converting the original 0-1 programming problem into a linear programming problem and then obtain the optimal solution by using branch and bound algorithm. We further prove that the network throughput is independent of the WMV's velocity under certain conditions. Performance of our proposed algorithm is evaluated through extensive simulations. The results validate the correctness of our proposed theorems and demonstrate that our algorithm outperforms two baseline algorithms in achieved throughput under different settings.

• Journal of the Korean Society for Library and Information Science
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• v.39 no.3
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• pp.165-182
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• 2005

This study examines the changed information-gathering environment of these days has indeed changed the patterns of reporters in their information seeking efforts. For the study, two groups of reporters were surveyed. The first group consists of 9 senior-level reporters working for daily papers with 15 years or more of journalism career, the second group 11 junior reporters who have been in the industry for less than 10 years. The surveying of these reporters has indicated significant change in their patterns of information-seeking endeavor, the dominant trend changing from reporters' putting an emphasis on off-the record types of information through person-to-person contacts to their new focus on made-public information. The senior-level reporters, identify person-to-person contacts as most valuable sources for information and take meetings with their contacts as providing critical opportunities for information-gathering. On the other hand, this examination has found junior reporters to be spending more time in collecting made-public information and paying more attention to acquiring a higher level of professionalism and greater analytical abilities. In short, this study confirms the ever-rising importance of making available a wider range of information for reporters.

• Journal of Digital Convergence
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• v.14 no.5
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• pp.283-291
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• 2016

The railroad is one of the most popular means of transport. However, railroad agencies are managing the railroad information and provide its service respectively. That is, because of managing the different information and its type, the user will not receive the correct and integrated information. Thus, it is needed to employ methods for converting the various types of railroad information into the unified railroad information. In this study, we investigated how to (semi-)automatically convert railroad information in each agencies to standard railroad information. Railroad passengers can use the railroad information service at a time, at a glance and in one place. In addition, we believe that there can be provided the opportunity to create an new service, which will dramatically develop a railroad information service through these systematic and integrated railroad information management.

• Journal of the Korea Society of Computer and Information
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• v.23 no.1
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• pp.75-84
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• 2018

In this study, the researchers attempted to automate the process of painting the characters on the road surface, which is currently done by manual labor, by using the information and communication technology. Here are the descriptions of how we put in our efforts to achieve such a goal. First, we familiarized ourselves with the current regulations about painting letters or characters on the road, with reference to Road Mark Installation Management Manual of the National Police Agency. Regarding the graphemes, we adopted a new one using connection components, in Gothic print characters which was within the range of acceptance according to the aforementioned manual. We also made it possible for the automated program to recognize the graphemes by means of the feature dots of the isolated dots, end dots, 2-line gathering dots, and gathering dots of 3 lines or more. Regarding the database, we built graphemes database for plotting information, classified the characters by means of the arrangement information of the graphemes and the layers that the graphemes form within the characters, and last but not least, made the character shape information database for character plotting by using such data. We measured the layers and the arrangement information of the graphemes consisting the characters by using the information of: 1) the information of the position of the center of gravity, and 2) the information of the graphemes that was acquired through vertical exploration from the center of gravity in each grapheme. We identified and compared the group to which each character of the database belonged, and recognized the characters through the use of the information gathered using this method. We analyzed the input characters using the aforementioned analysis method and database, and then converted into plotting information. It was shown that the plotting was performed after the correction.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.1
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• pp.27-35
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• 2008

A navigation system is one of the important components of an unmanned ground vehicle (UGV). A GPS receiver collects data signals transmitted by (Earth orbiting) satellites. However, these data signals may contain many errors resulting misinformation and depending on one's position (environment), reception may be impossible. The proposed self-driven algorithm uses three low-cost GPS in order to minimize errors of existing inexpensive single GPS's driving algorithm. By using reliable final data, which is analyzed and combined from each of three GPS's received data signals, gathering a vehicle's steering performance information and its current pin-point position is improved even with error containing signals or from a place where signal gathering is impossible. The purpose of this thesis is to explain navigation system algorithm using multiple GPS and compass sensor and prove the algorithm through experiments.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.10a
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• pp.48-49
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• 2009

This study predicts and compares the evacuation times of a training ship, which is easily influenced by gathering patterns of crews' onboard life style. As the results, the evacuation times of the high density, like meal time, take 1.5 times longer than the low density, like normal time. And it is also evaluated that the evacuation times of high density affected by evacuation speeds show 4 times higher than the low density.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.4
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• pp.22-33
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• 2018

Recently domestic manufacturing companies have been experiencing worsening profitability and stunted growth due to the long-term economic recession and the rapid rise of developing countries such as China and Southeast Asia. These difficulties force many companies to concentrate their core competencies on new value creation and innovation in order to gain momentum for new growth. Enterprise Resource Planning (ERP) has been considered as one of viable solutions. Among the various modules in ERP, shop floor control function in the production management module is rather limited. In order to overcome this problem, Manufacturing Execution System (MES) has been used as a subsystem which has a strong information gathering power and flexibility. Both systems interact closely with each other. In particular, ERP requires fast, accurate shop floor information at MES. This paper describes how to synchronize relevant information between ERP and MES with theory of constraints (TOC). The processing time information transmitted from the MES workplace is received at the ERP workplace. In the process, the received processing time is causing information distortion in ERP, when the information gathering standard of MES is different from the ERP information interpretation standard. The Drum-Buffer-Rope theory of TOC was applied to resolve this problem, therefore, information synchronization between both systems was made. As a precondition, the standard time of the upper ERP system was rearranged according to the capacity constraints resource. As a result, standard time restructuring has affected changes in labor costs. Standard labor costs have come close to actual ones, and information synchronization of MES transmission data has improved the reliability of standard product costs, such that it enabled various company-wide restructuring actions to be much more effective.

• Communications for Statistical Applications and Methods
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• v.7 no.2
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• pp.427-433
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• 2000

In this paper, we review several two-stage randomized response techniques for gathering self-report data when persons are asked sensitive question. Also efficiencies and privacy protections based on the two-stage randomized response procedures are compared. Finally, we find optimal parameter conditions.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10b
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• pp.131-133
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• 1999

요즘처럼 웹을 이용하여 저오 검색시 너무나 많은 양의 정보를 수집, 정리, 관리해야 하는 문제에 직면하게 되었다. 또한 인터넷상에는 기존의 텍스트 자료 이외에도 이미지, 사운드, 데이터 베이스 등 우리가 원하는 여러 유형의 자료가 존재한다. 하지만 웹상에서는 텍스트만을 위주로 자료를 검색, 수집, 분류를 한다. 이러한 문제점을 해결하기 위해 XML를 이용하여 정보의 종류에 관계없이 수집할 수 있다. 이 논문에서는 이동 에이전트를 이용한 정보 검색 모형을 제시하고 이때 이동에이전트가 정보의 표현방법으로 XML를 사용한다. 또한 XML의 계층적인 특성을 활용하여 XML 문서의 분류, 병합을 할 수 있다. 따라서 수집된 정보의 정리된 형태로 쉽게 얻을 수 있다.