• Journal of the Korea Convergence Society
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• v.8 no.10
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• pp.61-66
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• 2017

Recently, IoT technology is rapidly developing with the keyword "Anytime, Anywhere, Convenient". In addition, security problems in IoT systems are exploding and the damage is increasing as well. In this paper, we propose a method to develop IoT system safely by using internationally recognized CC evaluation in ICT by identifying the standardization and security technology development status defining IoT system security requirements. For this purpose, IoT system and service security aspects are analyzed. Based on this, it is possible to design the security functional requirements and to demonstrate the rationale of the security objective through the correspondence relation, and it is possible to design the protection profile for the IoT system. This is a sufficient basis for the development methodology to be presented in this paper because it is used as a means of referring to the set of security requirements of administrators, developers, and users.

• Journal of the Korea Society of Computer and Information
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• v.19 no.1
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• pp.65-76
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• 2014

In this paper, we propose a high-level programming language for packet processing called eFlowC and it supporting programming development environment. Based on the C language which is already familiar and easy to use to program developers, eFlowC maintains the similar syntax and semantics of C. Some features that are unnecessary for the packet processing has been removed from C, eFlowC is highly focused on performing packet data, database, string byte information checking and event processing. Design high-level programming languages and apply an existing language or compiler technology, language function and compilation process that is required for packet processing will be described. In order to use the DPIC device such as X11, we designed a virtual machine eFVM that takes into account the scalability and portability. We have evaluated the utility of the proposed language by experimenting a variety of real application programs with our programming environment such as compiler, simulator and debugger for eFVM. As there is little research that devoted to define the formats, meanings and functions of the packet processing language, this research is significant and expected to be a basis for the packet processing language.

• Spatial Information Research
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• v.12 no.4 s.31
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• pp.307-319
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• 2004

Managing GML data in traditional database systems is not efficient since It has not only characteristics of spatial data but also features of (semi) structured n documents. XML enabled database systems can manage U data efficiently, however they cannot handle spatial data. Spatial database systems are good at spatial data handling but those are inefficient for XML data. This paper proposes a storage method of GML data for spatial database systems in order to solve the problems. The proposed method generates spatial database schemas from GML application schemas and store GML data into SDBMS through the generated schemas. A prototype of the storage method has been implemented on the Postgre SQ/SPE system to show the proposed method is appropriate for storing GML data. As a result, the implemented system was able to store various GML data which had diverse XML structures and different size. Stored data size was smaller than GML files. Furthermore, spatial, non-spatial, and mixed content queries could be performed over the stored GML data as quickly.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.1
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• pp.43-50
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• 2016

NAND flash based storage devices adopts multi-channel and multi-way architecture to improve performance using parallel operation of multiple NAND devices. However, multiple NAND devices consume higher current and peak power overlap problem influences on the system stability and data reliability. In this paper, current waveform is measured for erase, program and read operations, peak current and model is defined by profiling method, and estimated probability of peak current overlap among NAND devices. Also, system level TLM simulator is developed to analyze peak overlap phenomenon depending on various simulation scenario. In order to remove peak overlapping, token-ring based simple power management method is applied in the simulation experiments. The optimal peak overlap ratio is proposed to minimize performance degradation based on relationship between peak current overlapping and system performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.1A
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• pp.57-65
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• 2007

The overlay multicast that has been recently presented as IP alternative for the IP multicast has been getting much persuasion by the computing power of the hardware and the advancement of the network techniques to enforce Routing in application-level. In an overlay multicast, the system resource and the network bandwidth must be utilized efficiently to service real-time HDTV images. Specifically, the system must consider the delay and the jitter that can be incurred at the application-level. In this paper, we implement a server and a client to broadcast HDTV, in the session composed by the existing overlay multicast protocol. The broadcasting server performs the service using a TV tuner, An HDTV camcorder, and files, clients constituting a multicast group relay the received data to other clients. At this time, the information that the clients report periodically, including their delay and the network state, to the server is used as an important information to maintain an overlay session. The implementation is based on the DirectX and its performance is evaluated by the LAN test bed that has been set.

• Journal of Information Management
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• v.40 no.1
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• pp.199-215
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• 2009

The web 2.0 concept rapidly spreads to the various field which is based on an opening, the participation, and a share. And the research about the recommendation system, that is the personalize feature, and social network is very active. In the case of the recommendation system and social network, it had been developing in the respectively different area and the new research toward the service model of a form that it fuses these is insignificant. In this paper, I'm going to introduce efficient social network which is called the researcher connection network. It is possible to recommend the researcher intellectually who studies the similar field by analyzing the usage log and user profile. Through this study, we could solved the network expandability problem which is due to the user passive participation and the difficulty of the initial network construction that is the conventional social network problem.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.70-70
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• 2016

하천시설물 설계, 시공 및 관리에 있어서 바닥전단응력은 매우 중요하다. 예를 들어, 호안 등 시설물의 허용 소류력을 계산하거나, 하천의 유사량을 예측하는 데 있어서 바닥전단응력이 기준으로 쓰인다. 정상 등류의 경우, 수로 내 수체에 작용하는 중력과 수로 바닥 및 측면에 작용하는 마찰력의 평형을 고려함으로써 바닥전단응력을 산정할 수 있다. 본 연구에서는 식생을 제외한 아크릴수로에서의 전단판의 움직임을 이용한 바닥전단응력 측정장치를 설계, 교정 및 검증을 실시하였다. 이 전단판은 수체와 바닥면에서 발생하는 마찰력에 의해 변위가 발생하고 이 변위를 바닥전단 응력으로 산정하였다. 직접 측정한 바닥전단응력은 기존에 연구된 두 가지 방법과 비교하여 검증하였다. 비교 검증을 위한 실험은 폭 0.3 m, 길이 10 m인 고속수로에서 Froude수 1이상, Reynolds수 20000이상의 사류이면서 난류인 상태로 실험을 진행하였으며 유속은 PIV을 이용하여 측정하였다. 비교 검증을 위한 첫 번째방법은 Reach-avrage공식을 기초로 manning의 평균 유속 공식을 이용한 바닥전단응력을 산정하는 방법으로 일반적으로 간단한 경험식을 이용하여 바닥 전단응력을 산정하는 방법이다, 두 번째는 Reynolds stress를 산정하는 방법으로 PIV를 통해 흐름방향의 연직프로파일의 유속을 측정 한 후 레이놀즈 분해법에 의해 산정된 난류 강도를 측정하여 Reynolds stress를 산정한 후 Shear stress를 산정하는 방법을 사용하였다. 마지막으로 본 연구에서 가로 0.14 m, 세로 0.14 m의 전단판으로 구성된 바닥전단응력 측정장치를 개발하여 실험을 진행하면서 앞에서 언급한 두가지 방법을 측정하는 동시에 장치를 이용하여 바닥전단응력을 직접측정하여 총 3가지 바닥전단응력을 비교하였다.

• Journal of the Korea Society of Computer and Information
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• v.25 no.12
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• pp.1-15
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• 2020

In this paper, we propose a novel method for converting the existing 2D processes in the design and construction phase of civil engineering, to the future BIM-based processes. First, we compare and analyze the actual application processes of the outputs of the existing 2D method and the outputs of the 3D BIM method, for the whole process of BIM design of earthworks and road structures and integrated utilization of quantity, process(4D) and construction cost(5D), in view of life-cycle. The proposed method acquire the outputs of the design phase integrating IFC international common standard file information and CBS/OBS/WBS standard classification scheme information, and acquire the outputs of the construction stage by using an integrated utilization module for quantity, process(4D) and construction cost(5D). Ultimately, we intend to commercialize the step by step technologies for BIM design and construction in civil engineering by using the proposed method.

• Journal of the Korea Society of Computer and Information
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• v.14 no.11
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• pp.61-71
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• 2009

Vehicle license plate is the only way to check the registrated information of a vehicle. Many works have been devoted to the vision system of recognizing the license plate, which has been widely used to control an illegal parking. However, it is difficult to correctly segment characters on the license plate since an illumination is affected by a weather change and a neighboring obstacles. This paper proposes a robust method of segmenting the character of the license plate on irregular illumination condition. The proposed method enhance the contrast of license plate images using the Chi-Square probability density function. For segmenting characters on the license plate, binary images with the high quality are gained by applying the adaptive threshold. Preprocessing and labeling algorithm are used to eliminate noises existing during the whole segmentation process. Finally, profiling method is applied to segment characters on license plate from binary images.

• Journal of Digital Convergence
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• v.20 no.3
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• pp.507-516
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• 2022

The purpose of this study was to examine the factors influencing on the smartphone usage time according to the happiness perceived by adolescents. This study underwent the approval procedure for using the raw data of the 13th (2017) Adolescents' Health Behavior Online Survey through the homepage of Korea Centers for Disease Control and Prevention and selected 54,603 persons of 12-18 age groups as subjects of the study. The analysis was performed after generating a complex sample plan file by assigning weights using the IBM SPSS 23.0 program. There were significant differences in general characteristics and physical & psychological characteristics according to the use of the smartphone in the happy group and the unhappy group (p<.05). And there was a statistically significant difference in factors affecting smartphone usage time between the group of adolescents who perceived as happy and the group who perceived themselves as unhappy. It is necessary to improve the quality of life by increasing the level of happiness through the correct use of smartphones among adolescents.