• Journal of Electrical Engineering and Technology
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• v.4 no.3
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• pp.315-322
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• 2009

Penetration and installation of a new dynamic technology known as Flexible AC Transmission Systems (FACTS) in a practical and dynamic network requires and force expert engineer to develop robust and flexible strategy for planning and control. Unified Power Flow Controller (UPFC) is one of the recent and effective FACTS devices designed for multi control operation to enhance the power system security. This paper presents a dynamic strategy based on Particle Swarm Optimization (PSO) for optimal parameters setting of UPFC to enhance the system loadability. Firstly, we perform a multi power flow analysis with load incrementation to construct a global database to determine the initial efficient bounds associated to active power and reactive power target vector. Secondly a PSO technique applied to search the new parameters setting of the UPFC within the initial new active power and reactive power target bounds. The proposed approach is implemented with Matlab program and verified with IEEE 30-Bus test network. The results show that the proposed approach can converge to the near optimum solution with accuracy, and confirm that flexible multi-control of this device coordinated with efficient location enhance the system security of power system by eliminating the overloaded lines and the bus voltage violation.

• Journal of Advanced Marine Engineering and Technology
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• v.8 no.1
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• pp.85-99
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• 1984

The stability of the two-phase flow in a heated channel is of great importance in the design and operation of the boilers and light water nuclear reactors, because it can cause flow oscillations and lead to a violation of thermal limits with resultant overheating of the channels and cladding. This paper presents a systematic evaluation to the variation effects of the basic four (4) dimensionless parameters in a homogeneous equilibrium model. The flow stability is examined on the ground of static characteristic curves. The complicated transfer function of flow dynamics which gives consideration to the transport lag of density wave is derived, and the transient flow stability is analysed by applying the Nyquist stability criterion in control engineering. The analysis results summed up as follows 1. The coolant flow becomes stable in large friction number and specific flow, while it is unstabale in small friction number and flow. 2. Large phase-change number and Froude number destabilize the two-phase flow, but small numbers stabilize it. The effect to variation of phase-change number is more dominant compared with Froude number. 3. The dynamic analysis is required to hold the sufficient safety of heated channels since only static results does not keep it. The special attention could be payed in the design and operation of heat engines, because the unstaable region exists within the stable boundary at small and middle phase-change number and Froude number.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.28 no.2
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• pp.8-17
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• 2005

This paper dealt with a kind of heterogeneous vehicle routing problem with known demand and time deadline of customers. The customers are supposed to have one of tight deadline and loose deadline. The demand of customers with tight deadline must be fulfilled in the deadline. However, the late delivery is allowed to customers with loose deadline. That is, the paper suggests a model to minimize total acquisition cost, total travel distance and total violation time for a fleet size and mix vehicle routing problem with time deadline, and proposes a heuristic algorithm for the model. The proposed algorithm consists of two phases, i.e. generation of an initial solution and improvement of the current solution. An initial solution is generated based on a modified insertion heuristic and iterative Improvement procedure is accomplished using neighborhood generation methods such as swap and reallocation. The proposed algorithm is evaluated using a well known numerical example.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.11 no.4
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• pp.229-237
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• 2011

As smart phones have become widely adopted, they have brought about changes in individual lifestyles, as well as significant changes in the industry. As the mobile technology of smart phones has become associated with all areas of industry, it is not only accelerating innovation in other industries such as shopping, healthcare service, education, and finance, but is also creating new markets and business opportunities. The preparation of thorough security measures for smart phones is increasing in demand. While offering excellent mobility and convenience, smart phones can be exposed to a range of violation threats. In particular, it is necessary to make efforts to develop a security system that can preemptively cope with potential security threats in the banking service area, which requires a high level of reliability. This paper suggests a security reference model that is considered for the smart phone-based joint mobile banking development project being undertaken by the Bank of Korea in 2010. The purpose of this study is to make a security reference model for a reliable smart phone-based mobile financial service, by recognizing the specific security threats directed toward smart phones, and providing countermeasures to these security threats. The proposed mobile banking security reference model is useful in improving system security by systematically analyzing information security threats to the mobile financial service, and by presenting the guideline for the preparation of countermeasures.

• Korean Journal of English Language and Linguistics
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• v.2 no.3
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• pp.305-327
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• 2002

This paper is in line with the attempts to examine two assumptions implied about the role of Universal Grammar (UC) in nonnative language acquisition: Are the EFL learners at disadvantage in acquiring UC-driven knowledge? Are there critical period effects in EFL learning? Based on the research with the seven studies of ESL and EFL adult learners performance on the Subjacency violation sentences, the paper investigates the extent to which the EFL adult learners can attain UG-driven knowledge represented by the Subjacency Principle. It also makes comparison of the EFL learners level of access to UG with that of their counterparts, the ESL learners. The research findings suggests that the EFL environment doesn't prevent the learners from acquiring target grammar in UG domain. That is, the current paper strongly suggests that the EFL adult-learners be able to acquire UG-driven knowledge to a considerable extent, at least as high as the ESL adult learners can attain. For the interpretation of the research results of the seven studies, Constructionist Hypothesis (CH) supported by a Minimalist Program (MP) assumption is employed. CH seems more plausible to account not only for incomplete acquisition observed among the beginning and intermediate level learners but also for the native-like competence acquired by advanced level L2 learners.

• IEIE Transactions on Smart Processing and Computing
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• v.1 no.1
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• pp.65-71
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• 2012

Mobile RFID is a new application that uses a mobile phone as an RFID reader with wireless technology and provides a new valuable service to users by integrating RFID and ubiquitous sensor network infrastructures with mobile communication and wireless Internet. Whereas the mobile RFID system has many advantages, privacy violation problems on the reader side are very concerning to individuals and researchers. Unlike in regular RFID environments, where the communication channel between the server and reader is assumed to be secure, the communication channel between the backend server and the RFID reader in the mobile RFID system is not assumed to be safe. Therefore it has become necessary to devise a new communication protocol that secures the privacy of mobile RFID-enabled devices. Recently, Lo et al. proposed a mutual key agreement protocol that secures the authenticity and privacy of engaged mobile RFID readers by constructing a secure session key between the reader and server. However, this paper shows that this protocol does not meet all of the necessary security requirements. Therefore we developed an enhanced mutual key agreement protocol for mobile RFID-enabled devices that alleviates these concerns. We further show that our protocol can enhance data security and provide privacy protection for the reader in an unsecured mobile RFID environment, even in the presence of an active adversary.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.3
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• pp.127-133
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• 2009

The pre-existing medical treatment was done in person between doctors and patients. EMR (Electronic Medical Record) System computerizing medical history of patients has been proceed and has raised concerns in terms of violation of human right for private information. Which integrates "Identification information" containing patients' personal details as well as "Medical records" such as the medical history of patients and computerizes all the records processed in hospital. Therefore, all medical information should be protected from misuse and abuse since it is very important for every patient. Particularly the right to privacy of medical record for each patient should be surely secured. Medical record means what doctors put down during the medical examination of patients. In this paper, we applies fingerprint identification to EMR system login to raise the quality of personal identification when user access to EMR System. The system implemented in this paper consists of embedded module to carry out fingerprint identification, web server and web site. Existing carries out it in client. And the confidence of hospital service is improved because login is forbidden without fingerprint identification success.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.3
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• pp.53-62
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• 2015

Recently, number of tablet or Smartphone users increased significantly in domestic and around the world. But violation of personal information such as leakage, misuse and abuse are constantly occurring by using mobile devices which is very useful in our society. Therefore, in this paper it will talk about the problems in the network environment of the mobile environment such as tablet and Smartphone, Mobile Malware, hacking of the public key certificate, which could be potential threat to mobile environment. This thesis will research for people to use their mobile devices more reliable and safer in mobile environment from invasion and leakage of personal information. In order to use Smartphone safely, users have to use Wi-Fi and Bluetooth carefully in the public area. This paper will research how to use App safely and characteristic of risk of worm and Malware spreading. Because of security vulnerabilities of the public key certificate, it will suggest new type of security certification. In order to prevent from the information leakage and infect from Malware in mobile environment without knowing, this thesis will analyze the improved way to manage and use the mobile device.

• Journal of Internet Computing and Services
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• v.17 no.1
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• pp.91-99
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• 2016

A security system in Android OS adopts sandbox and an permission model. In particular, the permission model operates the confirmation of installation time and all-or-nothing policy. Accordingly, the Android OS requires a user agreement for permission when installing an application, however there is very low level of user awareness for the permission. In this paper, the current status of permission requirement within mobile apps will be discovered, and the key inspection list with an appropriate method, when a mobile service provider autonomously inspects the violation of least privilege around financial companies, and its usefulness will be explored.

• Journal of Korean Society of Transportation
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• v.26 no.1
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• pp.89-100
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• 2008

The purpose of this paper is to analyze the differences between the severity of punishments for traffic laws related offenders and the choice of policy measures with a view to reducing traffic accidents. To this end, government data on the drivers given a sentence of license suspension or revocation were collected and analyzed in terms of sex, age, type of driver's license, driving career, number of traffic laws violations, and number of traffic accidents generated. The statistics of analysis of covariance and tests of significance were used and conducted to compare the effectiveness of punishment for the penalty and the incentive groups. The results showed that the incentive policy measure on the drivers who violate traffic regulations repeatedly is more effective to reduce the number of traffic offenders and traffic accidents.