• Journal of Information Technology Applications and Management
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• v.14 no.3
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• pp.49-77
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• 2007

Role-based access control (RBAC) models are recently receiving considerable attention as a generalized approach to access control. In line with the increase in applications that deal with spatial data. an advanced RBAC model whose entities and constraints depend on the characteristics of spatial data is required. Even if some approaches have been proposed for geographic information systems. most studies focus on the location of users instead of the characteristics of spatial data. In this paper. we extend the traditional RBAC model in order to deal with the characteristics of spatial data and propose new spatial constraints. We use the object-oriented modeling based on open GIS consortium geometric model to formalize spatial objects and spatial relations such as hierarchy relation and topology relation. As a result of the formalization for spatial relations. we present spatial constraints classified according to the characteristics of each relation. We demonstrate our extended-RBAC model called OOGIS-RBAC and spatial constraints through case studies. Finally. we compare our OOGIS-RBAC model and the DAC model in the management of access control to prove the efficiency of our model.

• ETRI Journal
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• v.38 no.5
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• pp.858-867
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• 2016

A high dynamic range (HDR) video service is an upcoming issue in the broadcasting industry. For compatibility with legacy devices receiving a non-constant luminance (NCL) signal, new tools supporting an HDR video service are required. The current pre-processing chain of HDR video can produce color noise owing to the chroma component down-sampling process for video encoding. Although a luma adjustment method has been proposed to solve this problem, some disadvantages still remain. In this paper, we present an adaptive color noise reduction method for an NCL signal of an HDR video service. The proposed method adjusts the luma component of an NCL signal adaptively according to the information of the luma component from a constant luminance signal and the level of color saturation. Experiment results show that the color noise problem is resolved by applying our proposed method. In addition, the speed of the pre-processing is increased more than two-fold compared to a previous method.

• Journal of the Korea Safety Management & Science
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• v.9 no.4
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• pp.99-112
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• 2007

In most recent years, the business competition has spreads over all fields of corporations and their management area regardless of time and place, which makes the survival environment of each enterprise fiercer. In order to secure a high position in the competitive market, the various firms has implemented many methods related to price, quality, and service efficiency. However, the implementation with only low price or high quality might be helpless to hold a high position in modem market. Moreover more attention should be paid to the internal business processes of an organization. Therefore, a new and different method should be searched or developed in order to win the competitive power among other enterprises. This research will focus on the improvement of the business processes within the non-manufacturing industry by applying Lean Six Sigma methodology. DMAIC method will be applied to improve the inbound and outbound logistics processes, manage the inbound and outbound vehicles, and control the receiving and shipping activities.

• Journal of the Korea Safety Management & Science
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• v.19 no.1
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• pp.123-129
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• 2017

This study aims to analyze the performance of the beneficiaries of the SMEs(Small and Medium Enterprises) support project that has been handled online on the 'BizOK System', which is the integrated support system for SMEs in Incheon, by comparing before and after receiving support. Various performance indicators can be used, but this study used the rate of increase in sales, exports and employed manpower collected by the 'BizOK System'. Moreover, to analyze the trend of business performance by corporate feature, this study grouped the businesses into 7 categories including sales, business history, number of employees and capital. The results of this study are expected to be used in drawing implications for business support policies by utilizing them as basic data for enhancing efficiency of the support project and establishing corporate policies.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.5B
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• pp.443-448
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• 2009

A boundary value of the velocity of data gathering node (DGN) and a critical value for training overhead beyond which the scheme will not be feasible for a Multiple Input Multiple Output (MIMO) based cooperative communication for energy-limited wireless sensor networks is proposed in this paper. The performance in terms of energy efficiency and delay for a combination of two transmitting and two receiving antennas is analyzed. The results show that a set of critical value of velocity and training overhead pair is present for the long haul communication from the sensors to the data gathering node. Finally a relation between training overhead and velocity is simulated.

• IE interfaces
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• v.19 no.1
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• pp.26-33
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• 2006

Many Firms consider the application of a cross-docking system to reduce inventory and lead-time. However, most studies mainly concentrate on the design of a cross-docking system. This study presents the method that selects the cross-docking center under the existing logistics network. Describing the operation environment to apply the cross-docking system, the selection criteria of the cross-docking center, and the main constraints of transportation planning under the environment of multi-level logistics network, we define the selection problem of the cross-docking center applied to a logistics field. We also define the simulation model that can analyze variously the cross-docking volume and develop the selection methodology of the cross-docking center. The simulation model presents the algorithm and influence factors of the cross-docking system, the decision criteria of the system, policy parameter, and input data. In addition, this study analyzes the effect of increasing the number of simultaneous receiving and shipping docks, and the efficiency of the overnight transportation and cross-docking by evaluating each scenario after simulating the scenarios with the practical data of the logistics field.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.8
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• pp.1827-1832
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• 2014

In this thesis, we use one by one each of the analog switch and a high-speed DAC instead of the DAC that two or more are used in transmitting and receiving antennas multiple systems, maintaining the advantages of the existing method, reducing design costs, physical to provide a method that can reduce the data converters from MIMO system can improve the economic efficiency and the size reduction of a basis.

• Journal of Information Processing Systems
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• v.13 no.4
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• pp.668-676
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• 2017

Recently, the importance of big data has been emphasized with the development of smartphone, web/SNS. As a result, MapReduce, which can efficiently process big data, is receiving worldwide attention because of its excellent scalability and stability. Since big data has a large amount, fast creation speed, and various properties, it is more efficient to process big data summary information than big data itself. Wavelet histogram, which is a typical data summary information generation technique, can generate optimal data summary information that does not cause loss of information of original data. Therefore, a system applying a wavelet histogram generation technique based on MapReduce has been actively studied. However, existing research has a disadvantage in that the generation speed is slow because the wavelet histogram is generated through one or more MapReduce Jobs. And there is a high possibility that the error of the data restored by the wavelet histogram becomes large. However, since the wavelet histogram generation system based on the MapReduce developed in this paper generates the wavelet histogram through one MapReduce Job, the generation speed can be greatly increased. In addition, since the wavelet histogram is generated by adjusting the error boundary specified by the user, the error of the restored data can be adjusted from the wavelet histogram. Finally, we verified the efficiency of the wavelet histogram generation system developed in this paper through performance evaluation.

• Journal of Power Electronics
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• v.18 no.1
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• pp.300-308
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• 2018

An online estimation method for wireless power transfer (WPT) systems is presented without using any measurement of the secondary side or the load. This parameter estimation method can be applied with a controlling strategy that removes both the receiving terminal controller and the wireless communication. This improves the reliability of the system while reducing its costs and size. In a wireless power transfer system with an LCCL impedance matching circuit under a rectifier load, the actual load value, voltage/current and mutual inductance can be reflected through reflected impedance measuring at the primary side. The proposed method can calculate the phase angle tangent value of the secondary loop circuit impedance via the reflected impedance, which is unrelated to the mutual inductance. Then the load value can be determined based on the relationships between the load value and the secondary loop impedance. After that, the mutual inductance and transfer efficiency can be computed. According to the primary side voltage and current, the load voltage and current can also be detected in real-time. Experiments have verified that high estimation accuracy can be achieved with the proposed method. A single-controller based on the proposed parameter estimation method is established to achieve constant current control over a WPT system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.8
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• pp.457-463
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• 2013

Nowadays, adsorption chillers have been receiving considerable attention, as they are energy saving and environmentally benign systems. A fin tube type heat exchanger in which adsorption/desorption takes place is required with more compact size. The adsorption chiller is expected to have high energy efficiency in utilizing the waste heat exhausted from a process. The objectives of this paper are to scrutinize the effect of design parameters on the adsorption performance, especially the fin pitch of the fin tube, and to develop an optimal design fin tube heat exchanger in a silica gel/water adsorption chiller. From the numerical results, the fin pitch of 2.5 mm shows the highest adsorption rate, compared to other fin pitches, such as 5 mm, 7.5 mm and 10mm. Also, the adsorption rate is affected by the cooling water and hot water temperature.