• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1263-1266
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• 1997

In a fault-tolerant modern manufacturing systms characterized by the configuration, in which automated redundant machines prone to unexpected failures are interconnected with other complex subsystems such as AGV's, robots, computer control systems to produce complete parts, faulures together with repairs and reconfigurations should be considered as the three basic events to be modeled for computing the performance of manufacturing systems. In this papre, transient analysis is applied to modular cell manufacturing systems form a performability viewpoint whose modeling adantage is that various performanc e measures can be evaluated compositely in the context of application. The hypothertical modular cells are modeled firstly with hybrid decomposition method and availability measures as special cases of performability are computed and comments on performabililty modeling analysis are mentioned.

• Journal of Computing Science and Engineering
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• v.2 no.2
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• pp.137-160
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• 2008

The increasing availability of personal location data pushed by the widespread use of location-sensing technologies raises concerns with respect to the safeguard of location privacy. To address such concerns location privacy-preserving techniques are being investigated. An important area of application for such techniques is represented by Location Based Services (LBS). Many privacy-preserving techniques designed for LBS are based on the idea of forwarding to the LBS provider obfuscated locations, namely position information at low spatial resolution, in place of actual users' positions. Obfuscation techniques are generally based on the use of geometric methods. In this paper, we argue that such methods can lead to the disclosure of sensitive location information and thus to privacy leaks. We thus propose a novel method which takes into account the semantic context in which users are located. The original contribution of the paper is the introduction of a comprehensive framework consisting of a semantic-aware obfuscation model, a novel algorithm for the generation of obfuscated spaces for which we report results from an experimental evaluation and reference architecture.

• Journal of Korea Multimedia Society
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• v.11 no.6
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• pp.891-902
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• 2008

The software once developed enters in to the $2^{nd}$ phase of its useful operational life, where it performs its functions for which it has been developed. This is an important phase of software life, wherein the developers and users have to assess the performance of the software to prolong its operational life with efficiency, effectiveness and economy. Performance of the software is based on the measurement of the quality characteristics to ascertain that it is meeting or exceeding the needs of customers in terms of its functionality, usability, efficiency, reliability, availability, maintainability, portability etc. These software quality attributes defined under ISO 9126 provide an overall good framework for assessing the performance of the software. This paper describes a Software Performance Assessment (SPA) model using the Goal-Question-Metric (GQM) paradigm which has been applied to the operational software in real context with successful results.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.106-106
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• 2018

Ecosystem service valuation is a crucial step for the sustainable management of watershed. In the context of various ecosystem services provided by watershed, this study, particularly deals with water yield computation in Bagmati Basin of Nepal. The water availability per population in Bagmati Basin is lowest compared to other basins in Nepal. Also, the rate of urbanization is rapidly growing over a decade. In this regard, the objectives of this study are 1) to compute the total water yield of the basin along with computation on a sub-watershed scale, and 2) Study the impacts of land use change on water yield based on CLUE-S model. For the study, Integrated Valuation of Environmental Services and Tradeoffs (InVEST), a popular model for ecosystem service assessment based on Budyko hydrological method is used to compute water yield. As well, CLUE-S model is used to study land use change, which is further related to study variation on water yield. The sub-watershed wise outcome of the study is expected to provide the guidelines for the effective and economic management of a watershed on a regional scale.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.3
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• pp.192-203
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• 2016

Uganda is a country blessed with the biggest number of mountain Gorillas in the whole world. These animals contribute at least 12% in revenue generation to the Tourism sector through tracking by both local and foreign tourists who pay for the tracking permits. However, Gorilla tracking is also a big challenge even in the presence of highly skilled and well-trained game rangers. Development and implementation of a secure Computer and Mobile based Gorilla Tracking (GT) system that uses GIS and GPS technologies would be the most ideal technology to use. Therefore, this study aimed to find out the critical factors that would affect the Behavioral Intention of the would-be users to successfully decide to use such GIS/GPS-GT system. We used the existing UTAUT model to integrate six factors such as Performance Expectancy, Effort Expectancy, Employee Peer Influence, Facilitating Conditions, Behavioral Intention and System Use. However, Infrastructure Availability and Non-Technical Facilitating Conditions were added to reflect Ugandan ICT context. This amended UTAUT model was used to carry out the survey. The questionnaire was emailed to 220 government employees in the fields of ICT, Tour and Travel, Environmental Groups officials and Farmers who garden near the game reserves. A total of 133 were obtained fully completed, whereas 127 were deemed usable thus yielding a response rate of 58%. The analysis results show that except for non-technical facilitating conditions, effort expectancy, peer influence, performance expectancy and infrastructure availability positively affects behavioral Intention to use GIS/GPS-GT. This indicates that people in Uganda don't bother about regulations and rules in regard to using information system. As long as the system does what they want it to, anything else does not matter. As an employee in an organization is told to use a system by their supervisor, they have no objection to otherwise they risk losing their job. This implies that, supervisors have a great responsibility in the process of developing, implementing and using the system in Uganda.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.5
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• pp.1013-1019
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• 2016

This paper describes a novel Context-awareness Markov Chain Prediction (CMCP) algorithm based on movement prediction using Markov chain in Delay Tolerant Network (DTN). The existing prediction models require additional information such as a node's schedule and delivery predictability. However, network reliability is lowered when additional information is unknown. To solve this problem, we propose a CMCP model based on node behaviour movement that can predict the mobility without requiring additional information such as a node's schedule or connectivity between nodes in periodic interval node behavior. The main contribution of this paper is the definition of approximate speed and direction for prediction scheme. The prediction of node movement forwarding path is made by manipulating the transition probability matrix based on Markov chain models including buffer availability and given interval time. We present simulation results indicating that such a scheme can be beneficial effects that increased the delivery ratio and decreased the transmission delay time of predicting movement path of the node in DTN.

• Journal of Korean Society of Archives and Records Management
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• v.18 no.4
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• pp.231-257
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• 2018

This paper aims to suggest a facet-based ontology model that can help sort and access records of dispersed families to address these problems. The facet systematically defines the categories of target concepts, which can create diverse and multiple access points. Using the top-down and bottom-up approaches, the facets, which consist of five upper classes and 18 lower classes, were derived for the records of dispersed families. The proposed ontology model was evaluated by real users. The results show that, overall, the ontology is complete and relevant in terms of access points, availability of context information of the records, and description elements for search and use of the records on dispersed families.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.47 no.2
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• pp.168-175
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• 2024

Due to the complexity of urban area, the city vehicle routing problem has been a difficult problem. The problem has involved factors such as parking availability, road conditions, and traffic congestion, all of which increase transportation costs and delivery times. To resolve this problem, one effective solution can be the use of parcel lockers located near customer sites, where products are stored for customers to pick up. When a vehicle delivers products to a designated parcel locker, customers in the vicinity must pick up their products from that locker. Recently, identifying optimal locations for these parcel lockers has become an important research issue. This paper addresses the parcel locker location problem within the context of urban traffic congestion. By considering dynamic environmental factors, we propose a Markov decision process model to tackle the city vehicle routing problem. To ensure more real situations, we have used optimal paths for distances between two nodes. Numerical results demonstrate the viability of our model and solution strategy.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.222-222
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• 2015

Vietnam is one of the most vulnarable countries affected by climate change and sea level rise. One of the consequences of climate change and sea level rise is the increase of salinity intrusion into the rivers which is challenging to irrigation systems in coastal areas. This indicates the necessary to study the ability of taking water through sluice gates of irrigation systems in coastal zones, especially in the dry season with the effects of climate change and sea level rise in the future. In this paper, Nam Thai Binh irrigation system is selected as a case study. The irrigation system is one of 22 biggest irrigation systems of the Red River delta in Vietnam located in coastal region. The computed duration is selected in dry season to irrigate for Winter-Spring crops. The irrigation water for the study area is taken from different sluice gates along the Red River and the Tra Ly River. In this paper, MIKE-11 model was applied to assess the ability of taking water for irrigation of the study area in current situation and in the context of climate change and sea level rise senario in 2050 (under the medium emissions scenario (B2) published by the Ministry of Natural Resources and Environment of Vietnam published in 2012) with different condition of water availability. The operation of the gates depends on the water levels and sanility conditions. The sanility and water level at different water intake gates of Nam Thai Binh irrigation system were simulated with different senarios with and without climate change and sea level rise. The result shows that, under climate change and sea water level rise, some gates can take more water but some can not take water because of salinity excess and the total water taking from the different gates along the rivers decrease while the water demand is increase. The study indicates the necessary to study quantitatively some recommended solutions in the study area particularly and in coastal region generally in Vietnam to ensure water demand for irrigation and other purposes in the context of climate change and sea level rise in the future.

• Journal of the Korean Operations Research and Management Science Society
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• v.38 no.1
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• pp.123-138
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• 2013

Keyword advertising has been used as a promotion tool rather than the advertising itself to online retailers. This is because the online retailer expects the direct sales increase when they deploy the keyword sponsorship. In practice, many online sellers rely on keyword advertising to promote their sales in short term with limited budget. Most of the previous researches use direct revenue factors as dependent variables such as CTR (click through rate) and CVI (conversion per impression) in their researches on the keyword advertising[14, 16, 22, 25, 31, 32]. Previous studies were, however, conducted in the context of aggregate-level due to the limitations on the data availability. These researches cannot evaluate the performance of keyword advertising in the individual level. To overcome these limitations, our research focuses on conversion of keyword advertising in individual-level. Also, we consider manageable factors as independent variables in terms of online retailers (the costs of keyword by implementation methods and meanings of keyword). In our study we developed the keyword advertising conversion model in the individual-level. With our model, we can make some theoretical findings and managerial implications. Practically, in the case of a fixed cost plan, an increase of the number of clicks is revealed as an effective way. However, higher average CPC is not significantly effective in increasing probability of purchase conversion. When this type (fixed cost plan) of implementation could not generate a lot of clicks, it cannot significantly increase the probability of purchase choice. Theoretically, we consider the promotional attributes which influence consumer purchase behavior and conduct individuals-level research based on the actual data. Limitations and future direction of the study are discussed.