• Journal of Korea Game Society
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• v.17 no.3
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• pp.53-62
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• 2017

VR content manipulation equipment is not easy for individuals to access because it requires high prices. Especially, in the case of a system for tracking the motion of the user among the VR contents, a separate optical sensor device using an infrared camera is generally used. The disadvantage of the optical sensor equipment is that the measurable range is dependent on the measurement direction when tracking the rotation motion when using only a single device. In order to solve the above problems, this paper shows that the inertial sensor of the smartphone, which is generally owned by the public, can track the rotational motion of the user regardless of the measurement direction . The system using the LeapMotion is used as the reference system, and the system using the smart phone is defined as the evaluation system, and the usability of the evaluation system is verified by comparing the user satisfaction of the two systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.12
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• pp.2891-2898
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• 2014

It is feasible to develop a fault tolerant system through module level redundancy on the Integrated Modular Avionics (IMA). However, its great implementation complexity is one of important challenges when asynchronous hardware environment is naturally assumed. To solve this problem, Physically Asynchronous Logically Synchronous (PALS) on IMA has been proposed. But, it has adaptation problem by not addressing specific architecture for IMA system. In the paper, we propose how to synchronize the input data on the IMA system under primary/secondary redundancy architecture by referring to existing PALS. In the proposed scheme, we introduce window frame by considering rate monotonic scheduling and analyze the adequate the synchronization time. Finally, we verify the feasibility of the proposed design pattern through the systematic experiments.

• The KIPS Transactions:PartB
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• v.18B no.4
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• pp.231-240
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• 2011

Many search algorithms have been implemented by many researchers on the world wide web. One of the best algorithms is Google using PageRank technology. PageRank approach computes the number of inlink of each documents then ranks documents in the order of inlink members. But it is difficult to find the results that user needs, because this method find documents not valueable for a person but valueable for the public. To solve this problem, We use the WordNet for analysis of the user's query history. This paper proposes a personalized search engine using the user's query history and PageRank Check. We compared the performance of the proposed approaches with google search results in the top 30. As a result, the average of the r-precision for the proposed approaches is about 60% and it is better as about 14%.

• Journal of the Korea Society of Computer and Information
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• v.17 no.12
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• pp.121-129
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• 2012

In this paper, we proposed WBAN system model to management an application that requires low rate data transfer in IEEE 802.15.4. We have to use different wireless sensor network technology to transfer different date rate and emergency message in medical application service. A suitable system model for WBAN and a WBAN MAC protocol in order to solve these existing system problems are proposed. Firstly, the priority queuing was applied to contention access period, and the system model which could guarantee transmission of a MAC command frame was proposed. Secondly, the MAC frame was newly defined to use the system model which was proposed above. Thirdly, WBAN CSMA/CA back-off algorithm based on data transmission rate was proposed to enhance data throughput and transmission probability of the data frame which does not have priority in the proposed WBAN system. The proposed algorithm is designed to be variable CSMA/CA algorithm parameter, depending on data rate. For the evaluation of WBAN CSMA/CA algorithm, we used Castalia. As a result of the simulation, it is found that the proposed system model can not only relieve loads of data processing, but also probability of collision was decreased.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.4
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• pp.325-336
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• 2013

FlashLinQ, one of the typical D2D communication systems developed by Qualcomm, considers a single-tone communication based distributed channel-aware link scheduling method to realize the link scheduling process with low control overheads. However, considering the frequency selective fading effect of practical multi-path channel, the single-tone based SIR estimation causes a critical scheduling error problem because the received single-tone signal has quite different channel gain at each sub-carrier location. In order to overcome this problem, we propose a novel link scheduling method based on CAZAC (Constant Amplitude Zero Auto-Correlation) sequence for D2D communication system. In the proposed method, each link has a unique offset value set for the generation of CAZAC sequences. CAZAC sequences with the cyclic offsets are transmitted using multiple sub-blocks in the entire bandwidth, and then each device can obtain nearly full-band SIR using a good cyclic cross-correlation property of CAZAC sequence.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.10 s.89
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• pp.983-995
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• 2004

This paper introduces a pre-compensation filter for compensating dispersive and resonant properties experienced along the usage of non-ideal wideband antennas in impulse communication systems. It has been well blown that the transmitted impulse signal becomes deformed because of dispersive and resonant characteristics. Accordingly, in spite of using ideal template signal at the correlator in coherent receiver, these impairments degrade overall performance attributed to low level of coherence. To overcome this problem this paper exploits a realization technique of pre-compensation filter purposely installed at transmitter whose stability is automatically guaranteed because it has an inversion form of minimum-phase ARMA (Auto-Regressive Moving Average) system. The performance of proposed scheme will be shown in results from computer simulations to verify its affirmative impact on impulse communication system with regarding several distinctively shaped antennas.

• Journal of Korea Game Society
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• v.3 no.2
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• pp.35-41
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• 2003

There arose problems of double investment about the game engine part when a lot of game software similar to the property and procedure processed in the game engine develop new game without the reference or reuse in the other games. In particular, using various software development processes is one of main problems of double investment when the enterprises for the game software development develop games now Accordingly, because it does not make standardization of process about the game engine, it does not understand and reuse products created in process of the other software development process in development now. Accordingly, the newly analyzed and designed software was big problems with the present game software about the game engine process similar to the other game software when the enterprises for any game software develop a special game. For solving these problems, this study is to suggest the process improvement about the game engine development, analysis of structure and relation, classification and combination method by the class and module, implementation of storage, and processor model in order to apply the development method based on the component.

• Journal of KIISE:Databases
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• v.31 no.4
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• pp.432-443
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• 2004

As the XML data has been widely used in the Internet, it is necessary to store and retrieve the XML data by using DBMSs. However, relational DBMSs suffer from the model difference between graph structure of the XML data and table forms in relational databases. We propose an ORDBMS-based DTD-dependent XML data management system Xing. Xing stores XML data in a DTD-dependent form in an object database. Since the object database schema has a graph structure and supports multi-valued attributes, mapping from an XML data model and queries into an object data model and OQLs is a simple problem. For rapid storing of large quantities of the XML data, we use SAX parser with customized Xing-tree which requires a small memory space compared with the DOM-tree. Xing also returns the query result in an XML document form. We have implemented the Xing system on top of UniSQL object-relational DBMS for the validity checking and performance comparison. For XML genome data from GenBank, and experimental evaluation shows that Xing can provide significant performance improvement (maximum 10 times) compared with the relational approach.

• The KIPS Transactions:PartA
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• v.12A no.6 s.96
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• pp.547-556
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• 2005

Online collaborative teaming, which has emerged as a new type of education in knowledge-based society, is being discussed actively in the areas of action learning at companies and project-based learning and inquiry-based learning at schools. It regards as an effective method for improving learners practical and highly advanced problem solving abilities, and for stimulating their absorption into learning through pursuing common goals of learning together. Different from individual learning, however, collaborative learning involves complicated processes such as organizing teams, setting common goals, performing tasks and evaluating the outcome of team activities .Thus, it is difficult for a teacher to promote and evaluate the whole process of collaborative learning, and it is necessary to develop systems to support collaborative learning. Therefore, in order to monitor and promote interaction among learners in the process of collaborative learning, the present study developed an extensible collaborative teaming supporting agent (ECOLA) in online learning environments.

• School Mathematics
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• v.19 no.4
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• pp.691-712
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• 2017

It is an important to develop teachers' statistical reasoning or thinking by teacher education. In this study, the "comparing two data sets" tasks is focused as a way to develop pre-service elementary teachers' reasoning about core ideas of statistics such as distribution, variability, center, and spread. 6 teams of each 4 pre-service elementary teachers participated on the tasks and their presentations are analyzed based on Pfannkuch's (2006) teachers' inference model in comparing two data sets. As a result, they paid attention to the distribution and variability in the statistical problem solving by the "comparing two data sets" tasks, and used their contextual knowledge to make a statistical decision. In addition, they used some statistics and graphs as the reference for statistical communication, which is expected to provide implications for improving statistical education. The finding implies that the "comparing two data sets" tasks can be used to develop statistical reasoning of pre-service elementary teachers. Some recommendations are suggested for teacher education by these tasks.