• Korean Journal of Environment and Ecology
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• v.1 no.1
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• pp.35-45
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• 1987

To survey trail damage and vegetational change around trail at Bukhan Mountain National Park in Korea, field survey was executed over Bukhan mountain district during August, 1987. Trail damage was surveyed for he section of 7.18km from Ui valley to Jeongnung valley in which user's density was high. Ground vegetation was surveyed with a belt-transect method from trail edge to forest and edge species were surveyed with a belt method along trail edge. Interrelation between trail damage and user's density was not dear. Damage class II of trail showed 23.9% of the surveyed section and class III showed 8.0% and class II and III of natural trail showed 19.7% and those of facilitated trail showed 12.3%. The length of damage class II and III requiring readjustment were estimated as 3.65 km and 1.22km from the main trail course of 15.3km at Bukhan mountain district. In case of no intervention to forest by users, vegetational change around trails was appeared up to 6-8 m from trailside. But in case of intervention to forest by users, vegetational change was not coincident with the change of soil hardness and was diverse locally. Quercus mongolica, Lespedeza cyrtobotrya and Rbo-dodendron mucronulatum were appeared as Raunkiaer frequency class E, and Weigela subsessilis. Lespedeza maximowiczii, Rhododendron schlippenbachii and Sorbus alnifolid were appeared as class D at trail edge of ridge-Quercus mongolica was appeared as class E and Rhododenderon mucrounulatium. Stephanandra incisa were appeared as class D at trail edge of midslope. Rhododenron mucronulatum. Lespedeza maximowiczii and Stepanandra incisa were appeared as class D at trail edge of valley. Lespedeza cyrtobotrya. Lespedeza maximowiczii and Stephanandra incisa were appeared as class D at trail edge of valley beside motorway.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.4
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• pp.117-124
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• 2015

As recent developing computing environments, service is provided without time or place's limitation, and it is constituted dynamically. Above all, in terms of education supporting system, there is need to conceive user's information and provide optimal service as to right with applying context awareness under Ubiquitous computing environment. It should have groundwork based on user location and time. It is requires service providing based on user location under the condition of class to offer appropriate service with the context. In addition, context information providing technology is needed to offer right education support service in the class, where are different context information. Hence, in this research it is suggested education supporting system to provide context-based for instructor. The framework of this system has a foundation within previous work about Multi-agent based Distributed Framework. To examine implementation of context-based education supporting system in Ubiquitous computing environments suggested by this report, arranging system can fit information relates to instructor's location for service applying in the class.

• Journal of Communications and Networks
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• v.8 no.1
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• pp.21-27
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• 2006

We present and analyze a class of limited sensing random access algorithms with powerful properties. The algorithms are implementable in wireless mobile environments and their operational properties are simple. Their throughput in the worst case of the limit Poisson user model is 0.4297, while this throughput degrades gracefully in the presence of channel feedback errors.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.5
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• pp.671-682
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• 1995

In this paper, we propose a multimedia query language MQL which defines and manipulates multimedia data as integration of monomedia data in time and space. The MQL is designed for a multimedia data model, called the object-relationship model, and based on the multimedia object calculus which formally describes operations on multimedia data. The SQL- like syntax for class definition and object manipulation, such as retrieval, insert, update, and delete, is defined. We show how the MQL can represent the user queries using composite temporal-spatial class structures and various relationships, such as equivalence and sequence.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.12
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• pp.4324-4342
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• 2014

Previous papers analyzed the throughput performance of the CDMA ALOHA system in Rayleigh fading channel, but they assume that the channel coefficient of Rayleigh fading was the same in the whole packet, which is not realistic. We recently proposed the finite-state Markov channel (FSMC) model to the throughput analysis of DS uncoded CDMA/unslotted ALOHA networks for fixed length data traffic in the mobile environment. We now propose the FSMC model to the throughput analysis of coded DS CDMA/unslotted ALOHA networks with variable length data traffic and one or two user classes in the mobile environment. The proposed DS CDMA/unslotted ALOHA wireless networks for two user classes with access control can maintain maximum throughput for the high priority user class under high message arrival per packet duration.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.129-138
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• 2001

This paper studies on the user-interface design elements for the vehicle interior layout of the Korean AGT(Automated Guideway Transit). These are based on the cultural environment and space consciousness of both ethnic and class differences. This means human- oriented interface design. In order to apply the user-interface design, it is necessary to find the examples of lightrail at the foreign country, and research and analyze their design trend. Then try to combine into a concept of user interface design and interior layout. This study will be expected to apply the Korean AGT as a guide.

• Proceedings of the Korea Society for Simulation Conference
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• 2005.05a
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• pp.100-105
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• 2005

Development of complex discrete event simulators requires cooperation between domain experts and modeling experts who involve the development. With the cooperation the domain experts derive user requirement and modeling experts transform the requirement to a simulation model. This paper proposes a method for consistency verification of simulation model in DEVS formalism against the user requirement in UML diagrams. It also presents an automated tool, called VeriDEVS, which implements the proposed method. Inputs of VeriDEVS are three UML diagrams, namely use case, class and sequence diagrams, and DEVS Graph, all in Visio; outputs of a verification result is represented in PowerPoint files.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.1
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• pp.249-256
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• 2011

Since various applications is converged in digital televisions, playing game on DTV will be available in the immediate future. Game programming of DTV is more difficult than that of PC in a viewpoint of game development. Since TV use very simple remote controller as user interface, mapping type, choice type, and one-button type are used among mobile game user interfaces. In addition, we suggest to use text class, numeral class, bitmap class, and shape class of DTV OSD middleware which is proven software, instead of developing new DTV-oriented game engine. The proposed interfaces can be applied in various game situations and allow intuitive and fast operations. By using OSD middleware, game actions can be subdivided into state structures, OSD objects can be used as game objects, and events and actions of remote controller keys are easily defined.

• Journal of Practical Engineering Education
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• v.14 no.2
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• pp.367-376
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• 2022

In this study, the user experience was analyzed from the learner's point of view, focusing on the metaverse platform 'Spatial'. SUS(System Usability Scale) was used to evaluate the usability of the metaverse platform 'Spatial' in a college class, and the Magnitude estimation technique was used to evaluate the immersion and satisfaction with the class. In addition, a questionnaire survey was used to collect user experience opinions on the use of 'Spatial' as a teaching tool. Looking at the usability evaluation results of the 'Spatial' system, the students evaluated the usability, immersion, and satisfaction quite positively. Looking at the user experience of metaverse platform 'Spatial', it was found that students highly valued Metaverse as an educational tool that can provide a place for many people to gather and communicate even in a non-face-to-face space. Compared to other online platforms, metaverse has advantages in ease of use, interaction, immersion, and interest. In particular, in addition to keyboard, touch, and display, interaction using the five senses such as voice, motion, and gaze was recognized as a great advantage. On the other hand, it was found that high openness, freedom, and interest factors can both promote learning and inhibit learning. Nevertheless, it is judged that the metaverse platform 'Spatial' can be effectively applied in college classes because it enables various interactions between instructor and learner or between learner and learner.

• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.4
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• pp.12-22
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• 1999

Operation of an electromagnetic shaker system using a Class-D amplifier may cause unacceptable electromagnetic interference to another electronic system, requiring the user to take whatever steps are necessary to correct the interference. A differential amplifier in a Class-D amplifier is used to decrease the effect of a common-mode noise voltage in a shaker system. To prevent a ground loop, a transformer is inserted in another shaker system. These methods show reduction of the unwanted vibration which has occurred before. A transformer in a charge amplifier was used to prevent a ground loop in a shaker system using a Class-AB amplifier a few years ago, but it was susceptible of noise in a shaker system using a Class-D amplifier. Hence we corrected a ground loop between a charge amplifier and a vibration control/analysis system without a transformer. The usefulness of this approach is illustrated by the results of experiments.