• Journal of KIISE:Information Networking
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• v.32 no.2
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• pp.123-133
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• 2005

In recent years, service discovery is one of the major technologies of home networks which head for a pervasive computing environment. However, existing service discovery techniques are difficult to understand semantics, and they only provide syntactic level service matching. To solve these problems, we have designed and developed ontology for semantic service discovery. Our ontology could enrich the amount of devices and services representations with semantics, and the relation of devices and service could be efficiently described through primitive service. For representing context information of devices, we describe attributes of device including location information, device status and etc. To determine whether the developed ontology can be applied to service discovery systems, we have implemented a semantic service discovery system by extension of the existing Jini lookup service. Also, we have evaluated our ontology with associated software environment according to some experiment scenarios, and have proved the usefulness of our ontology-based semantic service discovery system.

• Journal of Welding and Joining
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• v.34 no.2
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• pp.59-66
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• 2016

The Gas Metal Arc(GMA) welding, called Metal Inert Gas(MIG) welding, has been an important component in manufacturing industries. A key technology for robotic welding processes is seam tracking system, which is critical to improve the welding quality and welding capacities. The objectives of this study were to develop the intelligent and cost-effective algorithms for image processing in GMA welding which based on the laser vision sensor. Welding images were captured from the CCD camera and then processed by the proposed algorithm to track the weld joint location. The proposed algorithms that commonly used at the present stage were verified and compared to obtain the optimal one for each step in image processing. Finally, validity of the proposed algorithms was examined by using weld seam images obtained with different welding environments for image processing. The results proved that the proposed algorithm was quite excellent in getting rid of the variable noises to extract the feature points and centerline for seam tracking in GMA welding and could be employed for general industrial application.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.5
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• pp.9-17
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• 2008

This paper proposes a method of color reproduction considering the viewing conditions of a PDP TV. Because of a change of peripheral environments by a temporal and spatial location of observers, the ambient lightings should be considered in the process of color reproduction of displays. A conventional method enhances the contrast and saturation of images by controlling voltage gains in each channel, so that there is a limit to implementing the phenomenon of human adaptation. This method also faces difficulties in reproducing the perceived colors under a variety of viewing conditions. Accordingly, in order to solve this problem, we first characterize the device by considering the brightness and the flare effect. The chromatic adaptation is finally applied to reproduce colors in a PDP TV using the information from the viewing conditions by the sensor. The images reproduced by the proposed method are visually more superior to those reproduced by a conventional method in the experiments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.3
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• pp.700-712
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• 2011

Due to recently advanced electrical devices, human can access computer network regardless of working location or time restriction. However, currently widely used mouse, joystick, and trackball input system are not easy to carry and they bound user hands exclusively within working space. Those make user inconvenient in Ubiquitous environments.. In this paper, we propose multiple dimension human motion detection system based on wireless sensor networks. It is a portable input device and provides easy installation process and unbinds user hands during input processing stages. Our implemented system is comprised of three components. One is input unit that senses user motions and transmits collected data to receiver. Second is receiver that conveys the received data to application, which runs on server computer. Third is application that performs command operations according to received data. Experiments shows that proposed system accurately detect the characteristics of user arm motions and fully support corresponding input requests.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.1
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• pp.141-150
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• 2011

In this paper, we propose a Cross-Layer Cooperative Routing(CLCR) architecture to support transmission efficiency in mobile wireless sensor networks. The main features and contributions of the proposed architecture and method are as follows. First, the clustering which uses the location information of nodes is utilized as infrastructure. Second, a cross-layer strategy which uses the technologies of network layer, MAC layer, physical layer together to support transmission efficiency and channel efficiency for cooperative-aided routing and transmission. Third, we consider realistic approach in the view points of the mobile ad-hoc wireless sensor networks while conventional methods just consider fixed sensor network environments. The performance evaluation of the proposed method is performed via simulation using OPNET and theoretical analysis. The results of performance evaluation of the proposed CLCR show improvement of transmission efficiency by the proposed CLCR.

• Journal of Navigation and Port Research
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• v.38 no.5
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• pp.457-462
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• 2014

Indoor-positioning systems are useful to various applications. Navigation system is one of the most popular applications, which needs the information of directions of nodes' movements. Specifically the applications should get the information in real-time to properly show the current moving position of a node. In this paper, simple vector-based algorithms are proposed to compute amount and direction of changes of azimuth of mobile nodes' heading directions using existing indoor positioning systems in indoor environments where azimuth sensors do not work properly. Previous algorithms calculate the azimuth changes by too many steps of topology-based formula. The algorithms proposed in this paper get the amount of changes of azimuth by simple formula based on vector, and determine the direction of changes by the sign of value of simple formula based on the previous movement of nodes. The algorithms are much simpler and less error-prone than previous ones, and then they can detect changes in many location-based applications as well. The performance of the algorithms is proved logically and mathematically.

• Journal of the Korea Computer Industry Society
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• v.6 no.3
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• pp.465-476
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• 2005

The wireless sensor network consists of a number of sensor nodes which have physical constraints. Each sensor node senses surrounding environments and sends the sensed information to Sink. In order to alleviate the inherent vulnerability in security of the wireless sensor nodes with the hardware constraints, the lightweight security protocol is needed and a variety of research is ongoing. In this paper, we propose a non-hierarchical sensor network and a security protocol that is suitable for monitoring man-made objects such as bridges. This paper, furthermore, explores a two-layer authentication, key distribution scheme which distributes the key and location of a sensor node in advance, and an effective security routing protocol which can take advantage of the Sleep and Awake state. This also results in the increased data transfer rate by increasing the number of alternative routing paths and the reduced energy consumption rate.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.5
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• pp.535-543
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• 2024

Studies on estimating the underwater sound source localization using acoustic signal characteristics have mainly been conducted in shallow waters. Recently, technologies for stably and efficiently estimating the underwater sound sources localization using the underwater sound propagation characteristics of the Reliable Acoustic Path(RAP) in deep water areas are being studied. Underwater surveillance technology in deep sea areas is known to have the advantage of having low detection performance variability due to time-varying underwater environments and having a small shadow zone, making it easy to stably detect underwater sound sources and estimate location even from relatively long distance. In this study, we analyzed the sound propagation characteristics based on the actual marine environment in the deep sea of the Korean Peninsula and conducted a study to analyze the estimation performance of sound source depth using the broadband interference pattern of direct wave and sea surface reflected waves radiating from underwater sound sources.

• The Journal of the Korea Contents Association
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• v.9 no.4
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• pp.299-312
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• 2009

Unlike profit-seeking businesses, hospitals provide medical services to promote the public good in a way, and they need a reform of management to ensure sustainable growth in fast-changing medical environments. The key to the managerial reform is enhancing efficiency, and inefficient managerial practices and factors affecting that should be grasped first of all to boost the efficiency of hospital management. But evaluation methods that are prevalent in the private sector are hardly applicable to hospitals. The purpose of this study was to assess hospital efficiency by using a data envelopment analysis(DEA). The 2006 data on 74 residency training hospitals with 500 beds or more were analyzed. The selected input variables included the number of bed, the number of doctors, the number of nurses, the number of medical technicians, personnel expenses, management cost and materials cost. And the selected output variables were the yearly number of outpatients, the yearly number of inpatients, the number of operation cases and earnings. In addition, the influence of the type of hospital establishment, location, the year of foundation and the type of hospital on hospital efficiency was checked as well.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.9
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• pp.289-296
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• 2015

The explosive growth of information has been difficult for users to get an appropriate information in time. The various ways of new services to solve problems has been provided. As customized service is being magnified, the personalized recommendation system has been important issue. Collaborative filtering system in the recommendation system is widely used, and it is the most successful process in the recommendation system. As the recommendation is based on customers' profile, there can be sparsity and cold-start problems. In this paper, we propose personalized movie recommendation system using collaborative filtering techniques and context-based techniques. The context-based technique is the recommendation method that considers user's environment in term of time, emotion and location, and it can reflect user's preferences depending on the various environments. In order to utilize the context-based technique, this paper uses the human emotion, and uses movie reviews which are effective way to identify subjective individual information. In this paper, this proposed method shows outperforming existing collaborative filtering methods.