• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.2
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• pp.307-318
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• 2013

Smart grid is composed of variable domains including different systems, and different types of the access control are needed in the multiple domain. Therefore, the access control model suitable for the smart grid environment is required to minimize access control error and deny the unauthorized access. This paper introduce the access control requirements in the smart grid environment and propose the access control model, SG-RBAC, satisfied with the requirements. SG-RBAC model imposes constraints on the access right activation according to the user property, the role property, and the system property. It also imposes constraints on the delegation and the inheritance of access right according to temporal/spatial information and a crisis occurrence.

• KIISE Transactions on Computing Practices
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• v.23 no.9
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• pp.535-541
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• 2017

Today, the scale of the computer software market has increased, and massive sized software has been developed to satisfy diverse requirements. In this context, software complexity is increasing and the quality of software is becoming more difficult to manage. In particular, software reuse is important for the improvement of the environments of legacy systems and new system development. In this paper, we propose a method to reuse modules that are certified by quality. Reusable levels are divided into code area (method, class, and component), project domain, and business levels. Based on the coupling and cohesion of software complexity, we propose a reusable module extraction mechanism with reusability metrics, which constructs a visualization of the "reusable module's chunk" based on the method and class levels. By applying reverse engineering to legacy projects, it is possible to identify reusable modules/objects/chunks. If these modules/objects/chunks are to be reused to develop an extension system or similar new system, we need to ensure software reliability in order to reduce the time and cost of software development.

• The Journal of the Korea Contents Association
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• v.8 no.3
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• pp.127-137
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• 2008

Major purpose of brand establishment of city is to give pride for the citizen and to enhance the city value through improving city image. As modern society wants aggressive and active attitude from all fields, the city, which means as human place of residence, has to try to change for human life and prosperity. It is true that the establishment of brand is shown through politics, economy, society, culture and art, however travel effect and profit creation should be most important. In actual circumstance of our country, that travel deficit is getting increased. the brand establishment of city is more concerned. To build a city, history and time is essential elements. It may be impossible that consistent direction and meaning continue throughout long terms, but after all, the kernel of tourism contents is that idea and development is concentrated focusing consistent direction and meaning. To solve this, problem of strategy and direction was researched through analysis of foreign cities, and also understanding of future role of city in 21st century make a base for rebirth as international travel city. After city brand establishment based on continuous management, it is very important to make city which has strong image power.

• Journal of KIISE:Information Networking
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• v.27 no.2
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• pp.197-205
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• 2000

This paper proposes and evaluates a scheme which enhances real-time performance on the Ethernet-based residential network where cable length is very short and most of traffic passes through a specific device. The scheme aims at enhancing deadline meet ratio of the real-time traffic, for example, video stream by means of applying the functionalities such as queue discrimination and early packet discard as well as maintaining network load properly. The design includes the description on hardware interfaces along with the software modules such as scheduler, device driver and connection manager. The simulation results via SMPL suggest that the proposed network can be used as a cost-effective residential network. We also measure the permissible bandwidth for non-real-time traffic without degrading the performance of real-time traffic.

• Journal of KIISE:Information Networking
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• v.28 no.2
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• pp.229-235
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• 2001

With the explosive popularity of the World Wide Web, the low penonnance of network often leads web clients to wait a long time for web server's response. To resolve this problem, web caching (proxy) has been considered as the most efficient technique for web server to handle this problem. The placement of web proxy is critical to the overall penonnance, and Li et al. showed the optimal placement of proxies for a web server in the internet with the linear and tree topology when the number of proxies, ]M, is given [4, 5]. They focused on minimizing the over all access time. However, it is also considerable for target web server to minimize the total number of proxies while each proxy server guarantees not to exceed certain res(Xlnse time for each request from its clients. In this paper, we consider the problem of finding the optimal number and placement of web proxies with the lin~ar and tree topology under the given threshold cost for delay time.

• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.101-113
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• 2018

Systems such as military inspection equipment which it is important to acquire and evaluate data in real-time should be able to real-time processing at the operating system level. As technology advances, there is a demand for replacing existing equipment with mobile device, but mobile devices with Android are not suitable for systems requiring real-time performance. On Android, garbage collection ensures free memory, while other tasks are interrupted while this task is performed, which cannot guarantee periodicity of particular tasks. In this paper, we designed and implemented a structure to control execution garbage collection of Android to solve this problem. Real-time performance is ensured by controlling garbage collection during the time required for real-time operation, and RTiK(Real-Time implanted Kernel) is applied to ensure real-time performance on Android. In order to evaluate the performance, we measured the call period of the 5ms period task, and, only 34.31% of the task was guaranteed before the control, but the task period of 98.18% was satisfied through control, providing real-time performance to Android.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.6
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• pp.797-804
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• 2013

In this study, the authors develop a methodology for a diagnostic system with a vibration parameter that is influenced by environmental factors. The data tends to have a varying average over time. Often, these features are found in statistical data retrieved from a production line. If we utilize existing statistical techniques for these features, we could derive an incorrect diagnostic conclusion based on the different average values. To overcome the limitations of previous methods, the authors apply a function analyzed through regression analysis to predict the mean value and corresponding upper and lower limits at each stage. This technique also provides corresponding statistical parameters in varying dynamic means. To validate the proposed methods, we retrieve data from the engine assembly line of H Motors and verify the results.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.3
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• pp.166-178
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• 2012

In order to simulate storm surge for the west coast, complex physics of asymmetrical typhoon wind vortex, tide and wave are simultaneously incorporated on a fine finite element mesh extended to the North Western Pacific sea. Asymmetrical vortex based on maximum wind radii for each quadrant by JTWC's best tracks are input in pADCIRC and wave stress is accounted by dynamic coupling with unSWAN. Computations performed on parallel clusters. In hindcasting simulation of typhoon Kompasu(1007), model results of wave characteristic are very close with the observed data at Ieo island, and sea surface records at major tidal stations are reproduced with satisfaction when typhoon is approaching to the coast. It is obvious that increasing of local storm surges can be found by introducing asymmetrical vortex. Thus this approach can be satisfactorily applied in coastal hazard management against to storm surge inundation on low level area and major harbor facilities.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.989-992
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• 2008

In this paper, we are presenting a case that integrates ultra high strength concrete(150MPa) with surface-exposed concrete. Ahead of the field application, we carried out laboratory experiment and B/P Test for a basic property of concrete(slump flow, air content, 50cm flow time, elapse time change and compression strength) and productivity. The next, we conducted Mock-up Test using simulation specimen to evaluate infilling, surface-finishing and hydration heat of concrete. We had satisfactory results for a basic property and hydration heat of concrete. However at the time of field application, it was occurred rupture of formwork because of high lateral pressure of concrete, and then formwork was reinforced and case-in-place time was adjusted. And regardless of low and high frequency vibration, it occurred to surface-pockmark. In case that applies ultra high strength concrete to surface-exposed concrete, we estimate that it is important of systematic management and improvement of construction.

• The KIPS Transactions:PartD
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• v.14D no.2
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• pp.145-156
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• 2007

Recently, the needs for effective real time change detection algorithms for XML/HTML documents and increased in such fields as the detection of defacement attacks to web documents, the version management, and so on. Especially, those applications of real time change detection for large number of XML/HTML documents require fast heuristic algorithms to be used in real time environment, instead of algorithms which compute minimal cost-edit scripts. Existing heuristic algorithms are fast in execution time, but do not provide satisfactory edit script. In this paper, we present existing algorithms XyDiff and X-tree Diff, analyze their problems and propose algorithm X-tree Diff which improve problems in existing ones. X-tree Diff+ has similar performance in execution time with existing algorithms, but it improves matching ratio between nodes from two documents by refining matching process based on the notion of efficiency of matching.