• Journal of Korea Water Resources Association
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• v.52 no.5
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• pp.373-380
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• 2019

In this study, the optimum pump operation technique is suggested to decrease the damage rate of water distribution system. Pump operation system was developed to achieve the effective pump operation. Pressure sensors which can communicate with pumps are installed at the end of water distribution system. Pump operation system can control the pressure of water pump according to data sent from the pressure sensors. Therefore, water distribution system can reduce the pressure and maintain enough pressure which can supply the demand of water users. For proving effectiveness of new system, reliability model was introduced to compare the results of damage rates between the maintaining high pressure and selective pressure in water pump. Unsteady analysis was conducted with several scenarios. And the results were used to calculate the probability of pipe breakage. From the results, it was found that new pump operation system can reduce the energy usage and probability of pipe breakage by applying to pumps.

• International Journal of High-Rise Buildings
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• v.8 no.2
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• pp.107-116
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• 2019

The use of computational fluid dynamics (CFD) is becoming an increasingly popular means to model wind flows in and around buildings. The first published application of CFD to both indoor and outdoor building airflows was in the 1970's. Since then, CFD usage has expanded to include different aspects of building design. Wind tunnel testing (WTT) on buildings for wind loads goes back as far as 1908. Gustave Eiffel built a pair of wind tunnels in 1908 and 1912. Using these he published wind loads on an aircraft hangar in 1919 as cited in Hoerner (1965 - page 74). The second of these wind tunnels is still in use today for tests including building design ($Damljanovi{\acute{c}}$, 2012). The Empire State Building was tested in 1933 in smooth flow - see Baskaran (1993). The World Trade Center Twin Towers in New York City were wind tunnel tested in the mid-sixties for both wind loads, at Colorado State University (CSU) and the [US] National Physical Laboratory (NPL), as well as pedestrian level winds (PLW) at the University of Western Ontario (UWO) - Baskaran (1993). Since then, the understanding of the planetary boundary layer, recognition of the structures of turbulent wakes, instrumentation, methodologies and analysis have been continuously refined. There is a drive to replace WTT with computational methods, with the rationale that CFD is quicker, less expensive and gives more information and control to the architects. However, there is little information available to building owners and architects on the limitations of CFD for flows around buildings and communities. Hence building owners, developers, engineers and architects are not aware of the risks they incur by using CFD for different studies, traditionally conducted using wind tunnels. This paper will explain what needs to happen for CFD to replace wind tunnels. Ultimately, we anticipate the reader will come to the same conclusion that we have drawn: both WTT and CFD will continue to play important roles in building and infrastructure design. The most pressing challenge for the design and engineering community is to understand the strengths and limitations of each tool so that they can leverage and exploit the benefits that each offers while adhering to our moral and professional obligation to hold paramount the safety, health, and welfare of the public.

• Journal of the Korea Convergence Society
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• v.12 no.2
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• pp.179-184
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• 2021

In this study, the conversation behavior of users is investigated by using in-vehicle voice interaction system. The purpose of this study is to identify the elements of conversations that the users expect in voice interactions with systems and present the structural improvements to enable the voice interactions similar to those between people. To observe the users' behavior of voice interaction in the vehicle, the data through contextual inquiry are collected and the interview contents are analyzed by using the open coding. We have been able to explore the usefulness of voice interaction features, which are of great importance in that they increase the user's satisfaction with the features and their usage persistence. This study is meaningful in analyzing the user's empirical needs for the technology of interpersonal model from the perspective of conversation.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.10 no.4
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• pp.59-71
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• 2000

Due to the advance of computer and communication technology, intrusions or crimes using a computer have been increased rapidly while various information has been provided to users conveniently. As a results, many studies are necessary to detect the activities of intruders effectively. In this paper, a new association algorithm for the anomaly detection model is proposed in the process of generating user\`s normal patterns. It is that more recently observed behavior get more affection on the process of data mining. In addition, by clustering generated normal patterns for each use or a group of similar users, it is possible to identify the usual frequency of programs or command usage for each user or a group of uses. The performance of the proposed anomaly detection system has been tested on various system Parameters in order to identify their practical ranges for maximizing its detection rate.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.1
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• pp.33-42
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• 2002

We present a systematic way to armor a zero-knowledge interactive proof based identification scheme that has badly chosen keys. Keys are sometimes mistakenly chosen to be weak(neither random nor long), and a weak key is often preferred to a strong key so that it might be easy for human to remember. Weak keys severely degrade the security of ZKIP based identification schemes. We show using off-line guessing attack how the weak key threats the security of ZlKIP based identification schemes. For the proper usage of ZKIP, we introduce a specialized form of ZKIP, which has a secret coin-tossing stage. Using the secret coin tossing, a secure framework is proposed for ZKIP based identification schemes with weak key in the ideal cipher model. The framework is very useful in password based authentication and key exchange protocol

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.2
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• pp.45-54
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• 2006

As widespread of using digital documents in various fields, control the usage of digital document is needed. So, Digital Rights Management(DRM) will become a key component of digital document system, but absence of proper digital document DRM system, there is a real risk to lose important information when a hacker achieved intrusion in important system. This paper designs and implements digital document DRM system based on OMA(Open Mobile Alliance) DRM model and OpenOffice. We considered being a digital document DRM system to contain appropriate solution of security and document compatibility.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.6
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• pp.93-103
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• 2005

As the usage of XML documents increases the requirement of security for XML documents is growing. Especially it is very important to solve the problem of access control to XML object which shares in the environment where various users connect to each others. In this paper, we propose the access control model and mechanism which is combined with role hierarchy in the RBAC and hierarchical key derivation/assign method for the access to XML object. So we implement the access control mechanism by including hierarchical key derivation method. The technique, we proposed, gives not only the benefit in management which RBAC provides in access control to XML objects, but also it ran help derive a lower layer key from the higher layer user's. This feature decrease the number of keys managed in each role hierarchy in comparison with previous methods.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.1
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• pp.155-167
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• 2012

Cloud computing service is a next generation IT service which has pay-per-use billing model and supports elastically provisioning IT infra according to user demand. However it has many potential threats originating from outsourcing/supporting service structure that customers 'outsource' their own data and provider 'supports' infra, platform, application services, the complexity of applied technology, resource sharing and compliance with a law, etc. In activation of Cloud service, we need objective assessment standard to ensure safety and reliability which is one of the biggest obstacles to adopt cloud service. So far information security management system has been used as a security standard for a security management and IT operation within an organization. As for Cloud computing service it needs new security management and assessment different from those of the existing in-house IT environment. In this paper, to make a Information Security Management System considering cloud characteristics key components from threat management system are drawn and all control domain of existing information security management system as a control components are included. Especially we designed service security management to support service usage in an on-line self service environment and service contract and business status.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.6
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• pp.261-270
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• 2010

As the usage of social network service(SNS) increases recently, great attention has been shown to the information security in SNS. However, there has been little investment in SNS environment for security while preferential investment to attract subscribers has been made so far. Moreover, there is still a lack of confidence for investment effect and an absence of framework to analyze the threat factors of information security in SNS. In this paper, we propose to model for decision-making standard of SNS information security investment by the AHP. The result shows that 'service image' is the most important criterion for the decision of SNS information security. It also shows that 'Profile-squatting and reputation slander through ID thefts' and 'Corporate espionage' are important threat factors in SNS information security.

• Journal of Digital Convergence
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• v.19 no.6
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• pp.143-162
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• 2021

Research on consumers' perception and willingness to purchase Battery Electric Vehicles (BEVs) is necessary to simulate BEVs' deployment in South Korea because South Korea's BEVs market is still in the early stage. This paper derives a theoretical framework for consumer segmentation based on consumers' willingness to purchase before and after BEV usage experience. In particular, this study empirically evaluates consumers' willingness to purchase and concerns using the survey data from BEVs users in either Seoul or the Jeju region. The empirical results from logit models show that experienced consumers' concerns about the heater and air conditioning (HAC) in BEVs decreased the consumers' willingness to buy, while greater daily driving distances increased the consumers' willingness to buy. In addition, the empirical findings from ordered probit models show that experienced consumers' concerns about the short driving distance, the availability of maintenance service (i.e., A/S service) during unexpected events, and the difficulties of driving BEVs up-hill increased the degree of concern about HAC. This paper will provide insights related to consumer segmentation, R&D, marketing strategies, and policy design for policymakers and firms.