• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.1
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• pp.150-164
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• 2017

The development of an appropriate public service quality model has become increasingly recognised as an important subject of interest in the public sector as well as academia. In particular, the public systems enacted by governments are widely used and have a significant impact on national competitiveness. But few researches have been conducted to explore the quality dimensions of a public system service and empirically examine the relationship among related variables. Therefore, in this study, we strive to develop a quality measurement model of public system service that can be effectively used in practice. Using 601 samples gathered through a structured survey from project engineers, a conceptual quality model of public system is presented and discussed. Given the exploratory nature of this study, an exploratory factor analysis is used to investigate quality dimensions and partial least square (PLS) is employed in determining the structural relationships. From empirical results, we found that the quality dimensions of the public system had four distinct quality dimensions (design quality, environment quality, primary outcome quality, additive outcome quality). All four quality dimensions showed good representative factors in explaining user satisfaction. Perceived trust was proved to significantly mediate the relationship between quality dimensions and user satisfaction. Our research is expected to contribute to the literature by providing a good conceptual framework for assessing public system quality by linking four quality dimensions with user satisfaction. In particular, the developed model can elaborately measure process quality and multi-functional outcome quality of the system by the supplementation of design quality and additive outcome quality respectively. Practical implications are also suggested on the basis of our analysis.

• Journal of Broadcast Engineering
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• v.19 no.1
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• pp.3-13
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• 2014

This study as an exploratory study, investigates personal cloud service use which has been developed and distributed rapidly. Focusing on the user's characteristics and use behaviors, the influences of connected uses of platform and contents are empirically figured out. The results show that the contents which need small-data capacity like pictures and musics have been used very frequently in a cloud service. Second, 'platform-connected use' has been found out as the most influential factor in cloud service. SNS, e-mail, and personal innovativeness are also proved as significant factors. As a leading study analyzing theoretically the personal cloud service, it implies that it is necessary to consider the user's characteristics and use behaviors in developing cloud service in the market and making policy for promoting relevant industry.

• The KIPS Transactions:PartC
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• v.13C no.7 s.110
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• pp.913-922
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• 2006

It used exclusively the radio communication where is the TRS(Trunked Radio Service) at frequency where the person whom it does is specific with hitherto radio communication method differently frequency of the decimal which is allocated to the relay station it talks the at the room which the multiple user uses with commonness. The TRS system the most big feature is the region multiple group and order communication method. The TRS the composition of system is composed of the multi mind group, the each group is composed of the terminal of the users who have the objective which is similar relates in business contents. With above it follows in same multi objective and the connection of the form which is various or group communication accomplishes and quality case, a possibility a or of having many problem point in key distribution for a large scale communication there is it could be exposed to attack of the form which is various. There is a place where it accomplishes the communication which is safe at the TRS from research which it sees it investigates group key distribution method which is an essential element. The method which it sees when it reduces a communication frequency, it stands but is the user, it proposes the efficient group key distribution method it will be able to accomplish.

• Korean Journal of Remote Sensing
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• v.15 no.4
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• pp.349-356
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• 1999

Korea Multi-Purpose Satellite-l (KOMPSAT-l) has been developed by the Korea Aerospace Research Institute (KARI) with the aid of TRW and will be launched on the December 21, 1999 at the Vandenberg Air Base in CA, U.S. Now, the satellite application group in KARI is preparing for the service with the KOMPSAT-l satellite data. For the purpose of supplying good service to the users, data application planning has to be established before launching satellite. To use satellite data effectively, KARI makes a plan for data policy, data price, mission planning, and commercializing strategy. This study was carried out with the purpose of effective use of satellite data. For this purpose, KARI, first, made 60 user groups to use KOMPSAT-l data for public welfare and research sectors. These user groups include government, public corporations, institutes, and universities. KARI will offer the service to users through online using Internet. Secondly, KARI made a policy for the priority of KOMPSAT-l missions. These are classified by the mission priority, payloads, and operational states etc. Thirdly, KARI will make data policy and data price of KOMPSAT-l based on the basic master plan. Especially, data price will be determined at the KOMPSAT-l committee including Ministry of Science and Technology (MOST). KARI is also trying to commercialize the data with the domestic and foreign companies to expand the use of KOMPSAT-l data in the industries sector. Afterward in this study, KARI will continue the improvement for the effective distribution of KOMPSAT-l data for all users.

• Journal of Information Processing Systems
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• v.17 no.1
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• pp.37-50
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• 2021

Query applications based on nested data, the most commonly used form of data representation on the web, especially precise query, is becoming more extensively used. MapReduce, a distributed architecture with parallel computing power, provides a good solution for big data processing. However, in practical application, query requests are usually concurrent, which causes bottlenecks in server processing. To solve this problem, this paper first combines a column storage structure and an inverted index to build index for nested data on MapReduce. On this basis, this paper puts forward an optimization strategy which combines query execution service tree and frequent sub-query trajectory to reduce the response time of frequent queries and further improve the efficiency of multi-user concurrent queries on large scale nested data. Experiments show that this method greatly improves the efficiency of nested data query.

• International Journal of Internet, Broadcasting and Communication
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• v.7 no.2
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• pp.73-78
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• 2015

Touch panel is mainly applied to pressure type touch panel but it occur a low recognition rate and error during long-term use. So, it is partly applied to capacitive touch panel to compensate for these problems but it also can occur a same problems via pollutions. Touch technology has developed a various method but it is not used because of high costs and difficult installation process. So, in this paper, we proposed an input method of touchless panel using IrDA matrix. This method is conducted using an IrDA Matrix composed of depth sensor. It is possible to offer a various contents for multi user. The proposed technology need a development of a high sensitivity sensing method and high-speed processing method of position information for Seamless operation control. And, it is required high-precision drive technology. Also, we proposed a Seamless user recognition for interactive contents service through a touchless panel using IrDA matrix.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.10
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• pp.1999-2007
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• 2017

In this paper, we implement a multi-band network selection (MNS) system based on Linux operating system which determines the optimal communication link for given network conditions among the available LTE, very high frequency (VHF), and high frequency (HF). The implemented software consists of a network interface, an MNS server, and a user GUI. We perform indoor test to verify the function of the implemented MNS system using two sets of MNS system. To this end, two types of VHF communication links that follow ITU-R M.1842-1 Annex 1 and Annex 4 are emulated in software. In addition, the HF transmission (reception) port of one MNS is directly connected to the HF reception (transmission) port of another MNS. We demonstrate through indoor tests that the implemented MNS system can support seamless maritime communication service in spite of artificial disconnection or re-connection of LTE, VHFs, and HF. The implemented MNS system is applicable to various maritime communication services including e-navigation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.3
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• pp.249-257
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• 2013

Recently, data traffic is significantly increased by high rate data service. As a result, radio spectrum is considered one of the most scarce and valuable resources for wireless communications. For the solution of this problem, cognitive radio(CR) has been proposed as an efficient means to opportunistic spectrum sharing between primary (licensed) users and cognitive radio users. In this paper, user selection scheme in CR networks is proposed for additional consideration of secondary system. The proposed user selection scheme mitigates interference to primary user by using orthogonal channel vectors while improves performance of secondary system. Simulation results show that the proposed scheme achieves 1.62bps/Hz higher average throughput of whole system than one of the existing scheme.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.15-23
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• 2013

In this paper, we propose a session management and control architecture for N-Screen services, which enable users to change devices and transfer contents among user's devices during service by session transfer and split. In N-Screen services, users may have multiple devices with different attribute such as screen resolution, CPU capability and access network interfaces. Also, since users may change devices during service, or one user may use multiple stream, N-Screen services need to enable the user to share and transfer contents across N-Screen devices. We introduce the management and control servers to provide session split over user multiple devices and session continuity while changing device. Furthermore, the proposed architecture provides the device capabilities aware session continuity. In addition, the proposed scheme minimizes the session transfer delay and content server processing load. We present results that show the effectiveness and usefulness of proposed architecture.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.5
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• pp.25-33
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• 2010

Multi-media service has been changed into user based audio services, which service supports actively user's preference and interaction with the users. In the market, multi-media products which can support the highest audio-quality by using lossless audio technology have been released and object audio music which user can select the objects has been serviced. In this paper, we design user's preference information based object audio file format and audio scene description for storage and transmission media. The designed file format is designed based on MPEG-4 file format because high-quality audio codecs in MPEG-4 audio can be easily used and the track of file format can be flexibly controlled depend on the number of the instrument in music. The encoded audio data of each objects and encoded audio scene description by binary encoding that has independent track are packed in a file. The scene description for storage media is consist of full and object scene description, the scene description for transmission media has an essential description for object audio operation and a specific description for real audio sound. The designed file format based simulator is developed and it generates an object audio file with several scene descriptions. Also, the real audio sound is serviced by the interaction with user and the unpacked scene description.