• Journal of The Korean Association of Information Education
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• v.21 no.6
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• pp.639-646
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• 2017

As computational thinking(CT) is gaining focus as a key 21st century skill much attention has been paid to promoting CT through software education. However, more studies are needed to design and implement effective CT assessment methods. This study aims to investigate the effects of three CT assessment methods in a course designed to enhance CT competencies of 52 pre-service teachers with a non-computer science background during one semester. To analyze pre-service teachers' CT competencies, we used 3 CT assessment methods: (1) pre-and post-testing based on Bebras computational thinking challenge questions, (2) Dr. Scratch to analyze group scratch projects automatically, and (3) scratch exam designed in this study to evaluate the development of CT. Our results show the positive effects of integrating assessment methods for promoting CT competencies. We end this paper with the discussion of advantages and implications of this integration.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.5
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• pp.125-131
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• 2015

In order to vitalize the Rich Communication Service-e(RCS-e) service, RCS-e users need various ways to use RCS including RCS-e apps. A RCS standards organization has suggested Application Program Interface(API). Since it only dealt with functional requirements, it was not enough to implement the API. This paper suggests an open API framework that can utilize RCS-e through a web interface. By using the framework, web developers can implement various RCS-e-enabled web applications. A system architecture is defined for the framework. Call flows for establishing a RCS-e session between the framework and other nodes are defined. Also, rules and examples for translating protocols between them are provided. Finally, performance evaluation proves that the proposed framework does not add loads to the existing network infrastructure.

• Journal of Navigation and Port Research
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• v.38 no.2
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• pp.121-126
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• 2014

This paper suggests a new algorithm to provide low-cost GPS modules with DGPS service, which corrects the error vector in the already-calculated position by projecting range corrections to position domain using the observation matrix calculated from the satellite elevation and azimuth angle in the NMEA GPGSV data. The algorithm reduced the horizontal and vertical RMS error of U-blox LEA-5H module from 1.8m/5.8m to 1.0m/1.4m during the daytime. The algorithm has advantage in improving the performance of low-cost module to that of DGPS receiver by a software update without any correction in hardware, therefore it is expected to contribute to the vitalization of the future high-precision position service infrastructure by reducing the costumer cost and vender risk.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.2 s.332
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• pp.89-96
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• 2005

In this paper, we propose a customer premise platform for processing multimedia data service on the ATM network. The proposed platform has a specific AAL2 processor that includes AAL2 protocol and scheduler algorithm so as to off-load large potion of burden from host processor and make it easy to process multimedia data from the ATM network in real time compared with conventional platform in which AAL/ATM tasks are processed by software. The ATS scheduler that is implemented based on 2-level time slot ring provides a simple and efficient method for scheduling data of VBR-rt, UBR and CBR traffics. TMS320C5402 DSP is used to process voice-related tasks such as voice compression and voice packet manupulation and AAL2 processor is implemented on $0.35\;{\mu}m$ process line. We implemented the customer premise equipment for VoDSL service and tested the proposed platform on a test bed network. The experimental results show that the proposed equipment has the call success rate of $97\%$ at least and provides voice service of toll-qualify.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.10
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• pp.83-98
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• 2007

The handover between different radio access networks, especially where their coverage overlaps, suffers various complications since the different access networks provide different service characteristics. One way to reduce service interruptions and QoS (i.e., bandwidth, throughput, delay) degradations during the inter-technology handover is to reserve the required resource in advance. The resource reservation algorithm should minimize the handover latency and maximize the resource utilization based on the accurate estimation on mobile's location, velocity, movement pattern and service requirements. In this paper, we propose a resource reservation algorithm based on the mobile terminal velocity and the cell selection probability, which maximizes resource utilization ana reduces network overhead. We compare the proposed algorithm with PMS(Predictive Mobility Support) and VCDS(Velocity and Call Duration Support scheme) based on 3-layer network model under various scenarios.

• Journal of Digital Convergence
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• v.15 no.8
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• pp.183-193
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• 2017

Digital accredited certificates issued under the Digital Signature Act provide essential functionalities for online service, so certificates are used for various services such as online banking, e-government. However, certificates can be stolen by hackers and users need to install separate software to use certificates. Recently FIDO, which aims to solve the problems of password-based authentication and the lack of interoperability between authentication methods, is used for biometric authentication and TrustZone, hardware-based secure environment, is used for safe smartphone usage. In this paper, the new service method is suggested which uses FIDO-based biometric authentication and stores certificates in TrustZone. This method can not only improve security and convenience but also be easily applied to the service because it uses built-in functionalities of new smartphones such as biometric sensors and TrustZone. It is expected that people can use certificates in a safe and convenient way with this method.

• Journal of the Korean Institute of Telematics and Electronics
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• v.17 no.6
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• pp.33-37
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• 1980

The information display control system is designed and implemented on an automobile in which the conventional panel displays are replaced by electronic ones. The system hardware consists of three main parts, i. e., (i) the function select keyboard (ii) the central processing unit (iii) the displays, The system software consists of main routine and several interrupt service routine such as keyboaiuand display interrupt service routine:. The main routine handles various sensor inputs to generate the appropriate information for the driver such as running speed, available fuel quantity. coolant temperature, battery voltage, remaining distance to the destination , time of day, and so on. Finally the results of the field test of the system and some associated difficulties of realization problems are discussed.

• Journal of Advanced Navigation Technology
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• v.18 no.1
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• pp.14-21
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• 2014

In this paper, we devise a new ontology-based context-aware system to recognize the smart car information, in which driver's intent is utilized by information of car, driver, environment as well as driving state, driver state. So proposed system can handle dynamically risk changes by adding real-time situational awareness information. We utilize the camera image recognition technology for context-aware intelligent vehicle driving information, and implement information acquisition scheme OBD-II protocol to acquire vehicle's information. Experiments confirm that the proposed advanced driver safety assist system outperforms the conventional system, which only utilizes the information of vehicle, driver, and environmental information, to support the service of a high-speed driving, lane-departure service and emergency braking situation awareness.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6458-6465
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• 2015

Frequent change of mobile applications has become a burden to management of mobile services. Therefore, the development of mobile Web services, which the central management is easy, has increased. Tools which developers, as well as general users can easily develop, have been developed for mobile Web services. However, researches of standardized metamodel for implementing mobile Web service dynamically by general users is the inadequate situation. In this paper, we propose a dynamic metamodel for developing mobile Web services. The dynamic metamodel consists of a mobile Web pages, mobile Web page instance and dynamic connection using XDPL structure. we study a connection metamodel for condition connection, split connection and join connection, and combile entire metamodel, finally. Also, we carry out a case study in order to verify the suitability of metamodel by based on XPDL.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.620-627
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• 2017

An open sharing market is a market providing a sharing business. It provides open sharing services handling various products, unlike existing sharing services providing specific products. Sharing under an open sharing market can include all products that are difficult for customers to deal with, and provides fluidity of trade through negotiating sharing periods and costs among sharers. There are many variant elements when you provide sharing services for various products. Therefore, in this paper, we propose an extensible architecture that can reflect the variant elements in open sharing markets. We expect the proposed architecture can continuously improve the extensibility of sharing services for various products, because we design sharing services as components to efficiently manage and provide various sharing services, and provide dynamic binding of variant elements.