• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.6
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• pp.1077-1082
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• 2019

The development of computing technology and networking has developed into a fundamental technology of the Fourth Industrial Revolution, which provides a ubiquitous environment. In the ubiquitous environment, the IoT environment has become an issue so that various devices and the things can be actively accessed and connected. Also, the RFID system using the wireless identification code attaches an RFID tag to the object, such as the production and distribution of products. It is applied to the management very efficiently. EPCglobal is conducting a research on RFID system standardization and various security studies. Since RFID systems use wireless environment technology, there are more security threats than wire problems. In particular, failure to provide confidentiality, indistinguishability, and forward safety could expose them to various threats in the Fourth Industrial Revolution. Therefore, this study analyzes the standard method of EPCgolbal and proposes RFID security method using hash code that can consider the amount of computation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.432-436
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• 2016

The cooler, which is the main part in a Thermal Observation Device (TOD), makes the TOD function by reducing the temperature. As the cooler is imported, overseas enterprises presented 20,000 hours as the operation time and the military have used the cooler as presented. However, failures have occurred occasionally after mass production stage. Therefore, we need to analyze the MTBF of the TOD cooler. So, military and defense industry companies collected the failure data of the TOD cooler. We analyze the MTBF of the TOD cooler using survival probability function and failure data. We find the optimal distribution by applying parametric method and estimate parameters. We determine that the Log-logistic distribution is the most appropriate for this data. Also, we analyze the reliability per hour of the TOD cooler. The result of MTBF of the TOD cooler was higher than that of presented by oversee enterprises.

• Journal of Korean Society of Transportation
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• v.18 no.5
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• pp.99-107
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• 2000

Path-based assignment(PBA) is valuable to dynamic traffic control and routing in integrated ITS framework. As one of widely studied PBA a1gorithms, Gradient Projection(GP) a1gorithm typically fields rapid convergence to a neighborhood of an optimal solution. But once it comes near a solution, it tends to slow down. To overcome this problem, we develop more efficient path-based assignment algorithm by combining Conjugate Gradient method with GP algorithm. It determines more accurate moving direction near a solution in order to gain a significant advantage in speed of convergence. Also this algorithm is applied to the Sioux-Falls network and verified its efficiency. Then we demonstrate that this type of method is very useful in improving speed of convergence in the case of user equilibrium problem.

• Journal of Korean Society of Transportation
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• v.26 no.5
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• pp.175-184
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• 2008

Uncertainties are unavoidable in engineering applications. In this paper we propose an alpha reliable multi-variable network design problem under demand uncertainty. In order to decide the optimal capacity enhancement, three performance measures based on 3E(Efficiency, Equity, and Environmental) are considered. The objective is to minimize the total budget required to satisfy alpha reliability constraint of total travel time, equity ratio, and total emission, while considering the route choice behavior of network users. The problem is formulated as the chance-constrained model for application of alpha confidence level and solved as a lexicographic optimization problem to consider the multi-variable. A simulation-based genetic algorithm procedure is developed to solve this complex network design problem(NDP). A simple numerical example ispresented to illustrate the features of the proposed NDP model.

• Convergence Security Journal
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• v.12 no.6
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• pp.85-92
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• 2012

There are many software reliability models that are based on the times of occurrences of errors in the debugging of software. It is shown that it is possible to do asymptotic likelihood inference for software reliability models based on infinite failure model and non-homogeneous Poisson Processes (NHPP). For someone making a decision about when to market software, the conditional failure rate is an important variables. The finite failure model are used in a wide variety of practical situations. Their use in characterization problems, detection of outliers, linear estimation, study of system reliability, life-testing, survival analysis, data compression and many other fields can be seen from the many study. Statistical Process Control (SPC) can monitor the forecasting of software failure and there by contribute significantly to the improvement of software reliability. Control charts are widely used for software process control in the software industry. In this paper, we proposed a control mechanism based on NHPP using mean value function of log Poission, log-linear and Parto distribution.

• Journal of Korea Society of Industrial Information Systems
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• v.5 no.4
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• pp.16-21
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• 2000

Role Based Access Control(RBAC) reduces the cost of administering access control policies as well as making the process less error-prone. Administration tool is most important component in the concept of RBAC. The administration tool for the RBAC security system must be maintain the integrity of user-role and role-role relationships in the RBAC Database. Therefor, it is required set functions, properties defining integrity of database. When it will be designed security systems which is applying RBAC policy on the Linux(server system environments, this paper defines integrity of database for user-role and role-role relationships, and we propose formal specification of operation in order to manage these relationships. The proposed formal specification leads to the consistency requirements for the RBAC database which are defined as a set of relationship. Also, this paper can easily derive the implementation of the RBAC administration tool by formal specification of operations. It leads us tn the minimal set for a more efficiently implementation of administration tool.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.2
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• pp.117-123
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• 2018

In this study, we suggest a fast image reconstruction scheme using Poisson equation from image gradient domain. In this approach, using the Poisson equation, a guided vector field is created by employing source and target images within a selected region at the first step. Next, the guided vector is used in generating the result image. We analyze the problem of reconstructing a two-dimensional function that approximates a set of desired gradients and a data term. The joined data and gradients are able to work like modifying the image gradients while staying close to the original image. Starting with this formulation, we have a screened Poisson equation known in physics. This equation leads to an efficient solution to the problem in FFT domain. It represents the spatial filters that solve the two-dimensional screened Poisson model and shows gradient scaling to be a well-defined sharpen filter that generalizes Laplace sharpening. We demonstrate the results using a discrete cosine transformation based this Poisson model.

• Journal of Korea Port Economic Association
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• v.31 no.1
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• pp.171-188
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• 2015

Logistics network has been increasingly acknowledged as one of the important driving force for economic development in China. With the scope of logistics effect broadening and the development of logistics infrastructure, both logistics network and economy in terms of GDP in China has experienced rapid development hand in hand. This paper investigates the relationship between logistics network and economic growth, using a dataset covering 31 provinces over the period from 2003 to 2012 in China. Factor analysis is applied to obtain a total evaluation of logistics function defining the impact of logistics network on the national economy growth. According to fixed effect panel data approach, a significant and positive impact of logistics network on economic growth in China is found, meanwhile, a comparative analysis regarding economic development between coastal provinces and interior provinces is also conducted. The results suggest that the impact of logistics network on economic growth is higher in eastern provinces than that in western provinces. The policy implication for other nations, in particular for developing nations, is logistics network should be regarded as an important driving force for economic development, and investment should be made in advance to achieve the best efficiency in economic development and planning.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.5
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• pp.131-137
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• 2011

Recently Lin et al. proposed a simple remote user authentication scheme using smart cards. But the proposed scheme has not satisfied security requirements which should be considered in the user authentication scheme using the password based smart card. In this paper, we show that Lin et al.'s scheme is insecure against off-line password guessing attack. In their scheme, any legal user's password may be derived from the password guessing when his/her smart card is stolen and the secret information is leaked from the smart card by an attacker. Accordingly, we demonstrate the vulnerability of their scheme and present an enhancement to resolve such security weakness. Our proposed scheme can withstand various possible attacks including password guessing attack. Furthermore, this improved scheme can provide mutual authentication to improve the security robustness. Performance evaluation shows that the proposed scheme is relatively more effective than Lin et al.'s scheme.

• Fire Science and Engineering
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• v.30 no.3
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• pp.16-22
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• 2016

Fire fighters rely on fire fighter protective clothing (FFPC) to provide adequate protection in the various hazardous environments. To enhance its protection performance, the FFPC material must be thick and thus it is difficult to achieve weight reduction. One of the methods of overcoming this problem, the addition of phase change material (PCM) to FFPC, is a new technology. In previous studies, the researches was mostly related to the temperature characteristics of the fibers incorporating PCM, but little information is available about its effect on burn injuries. Thus, in this study, the inhibitory effects of adding PCM to FFPC on second degree burns were investigated through numerical calculations. Thermal analyses of biological tissues and FFPC with embedded PCM exposed to several fire conditions causing severe tissue damage were studied by using a finite difference method based on the Pennes bio-heat equation. FFPC with embedded PCM was found to provide significantly greater protection than conventional fire fighting clothing, because the heat of absorption due to the phase change within the material is used to limit the heat conduction of the material.