• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.4C
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• pp.277-282
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• 2012

In this paper, we present a real-time eye contact system for realistic telepresence using a Kinect depth camera. In order to generate the eye contact image, we capture a pair of color and depth video. Then, the foreground single user is separated from the background. Since the raw depth data includes several types of noises, we perform a joint bilateral filtering method. We apply the discontinuity-adaptive depth filter to the filtered depth map to reduce the disocclusion area. From the color image and the preprocessed depth map, we construct a user mesh model at the virtual viewpoint. The entire system is implemented through GPU-based parallel programming for real-time processing. Experimental results have shown that the proposed eye contact system is efficient in realizing eye contact, providing the realistic telepresence.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.4B
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• pp.227-235
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• 2012

Holes that generated by the unpredictable and harsh nature application environment or uneven energy consumption are an inevitable phenomenon in wireless sensor networks. Most of the existing schemes for this hole problem tend to use a static detour path to bypass a hole. The static detour path may lead to uneven energy consumption of the nodes on the boundary of the hole, thus it may enlarge the region of holes. At the same time, traffic would concentrate on the nodes on the boundary of the hole and tend to be depleted quickly. To solve this problem, we introduce energy-efficient grid-based geographic routing and hole-detouring scheme by taking advantage of grid anchor point in wireless sensor network with holes. The location of hole detour anchor node is dynamically shifted in grid cell. just generating dynamic hole detour paths to reduce total energy consumption. Simulation results are provided to validate the claims.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8B
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• pp.751-759
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• 2009

Due to the advance of WLAN technology, the use of the multimedia service such as the video streaming service has been increased in the home network. However, we need to study the method which decreases the transmission delay and the frame loss rate to provide QoS of the video streaming service. Therefore, this paper proposes an active buffer management mechanism to guarantee QoS of the streaming service in IEEE 802.11e EDCA. The proposed protocol discards the frame in the HoL of the buffer based on the importance of each frame and the virtual transmission delay of frame newly arriving at the buffer. In the simulation results, the proposed algorithm not only decreases the frame loss probability of important I and P frames but also stabilizes the transmission delay. It may increase the QoS of video streaming services.

• The KIPS Transactions:PartC
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• v.19C no.2
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• pp.149-152
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• 2012

In the roaming case, the cost of using the visited network is larger than that of home network. So, if a mobile terminal is connected to the visited network, even though it actually came back to the home network, the user may unduly pay for communication. Such a problem frequently occurs when many networks are overlapped in the same region, as shown in the case of Poland. In this paper, we propose a network search algorithm to support the fast comeback to home network in the roaming environment. In the proposed scheme, which is based on the 3GPP specification, the mobile terminal tries to search the home network by using a database of network information, as fast as possible. For performance evaluation, we construct a virtual testbed with real terminal and network equipment to emulate the service providers in Poland. From the experimental results, we can see that the proposed scheme can reduce the time of comeback to the home network by 3~60 minutes, compared the existing 3GPP scheme.

• The KIPS Transactions:PartB
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• v.18B no.4
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• pp.193-200
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• 2011

This paper proposes a low-cost visual analyzer algorithm of human body motion for real-time applications such as human-computer interfacing, virtual reality applications in medicine and telemonitoring of patients. To reduce cost of its use, we design the algorithm to use a single camera. To make the proposed system to be used more conveniently, we avoid from using optical markers. To make the proposed algorithm be convenient for real-time applications, we design it to have a closed-form with high accuracy. To design a closed-form algorithm, we propose an idea that formulates motion of a human body joint as a 2D universal joint model instead of a common 3D spherical joint model, without any kins of approximation. To make the closed-form algorithm has high accuracy, we formulates the estimation process to be an optimization problem. Thus-desined algorithm is applied to each joint of the human body one after another. Through experiments we show that human body motion capturing can be performed in an efficient and robust manner by using our algorithm.

• The KIPS Transactions:PartD
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• v.15D no.4
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• pp.569-580
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• 2008

Web services are the current most promising technology for service oriented architecture(SOA) implementations. However, in spite of the large scale acceptance of web services, they have been relegated to internal integration projects, and the grand vision of virtual enterprises where partners can be integrated on demand is yet to be realized. The main reason is that the current standards of web services are not very suitable for the dynamic web service discovery and integration. In this paper, we present a novel SemanticBPEL solution that merges the benefit of WS-BPEL, with the advantage of OWL-S for building a semi-automatic web service composition system. In particular, this work proposes a multi-phase search method for solving dynamic discovery and integration problems of web services. The proposed method is compared with the existing keyword based retrieval method. These comparisons show that our approach outperforms the existing method.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.7
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• pp.393-400
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• 2003

In this paper we deal with the virtually zero power control for the rigid rotor with radial suspension by the permanent magnetic bearing and axial suspension by electromagnetic bearing. The purpose of the virtually zero power control is to reduce the power consumption of the electromagnetic bearings. The axial active force is expressed by the normal second order equation which has only one degree-of-freedom. The virtually zero power control structure has two schemes. One is the coil control current integrator which is used to make the convergence of the control current to a range which is very close to zero. By using the current integrator the DC component which is included in the control current is eliminated, thus the control current converges to a range which is close to zero. The other is normal PD control loop which is used to make the rotor reach to stable equilibrium point and to maintain air gap so that the axial force produced by radial permanent magnet always balances the total weight of the rotor and its load. First we show a simple mathematical plant model and the virtually zero power (VZP) control blocks. Second, we investigate the theoretical feasibility and the stability of the proposed virtually zero Power control levitation system with PD feedback loop by using linear control theory Finally we show the effectiveness of the proposed control method to reduce the power consumption by simulations.

• Convergence Security Journal
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• v.20 no.1
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• pp.15-24
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• 2020

Cyber terror and cyberwarfare are no longer virtual, but real, and as an actual security situation, it is necessary to have new understanding through expanding the concept of war to neutralize not only the other country's military command system, but also the country's main functions such as telecommunications, energy, finance, and transport systems, and it also needs to establish the future development strategy of cyber terror response at the national level. Through analysis of cyberwarfare trends in each country and current status of cyberwarfare in Korea, it will systematically explore the demand of new policy based on laws and systems, including the strategies of cyber security technology development, industry promotion, and manpower training and existing information protection policies. through this, it effectively manages a sustainable national crisis, and it suggests to establish a future strategy for the medium and long term cyber security that can effectively and actively respond to cyberwarfare.

• KSBB Journal
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• v.6 no.4
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• pp.413-424
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• 1991

The optimal condition for manufacturing the yoghurt by using B. bifidum and L. acidophilus was studied. Optimal growth condition of B. bifidum and fermentation effects of B. bifidum, L. acidophilus and Str. thermophilus in mixed culture were investigated separately. Fermentation conditions of B. bifidum were optimized in 12% reconstitued skim milk. The addition of BIOS 2000 to 12% skimmilk was effective on the growth and acid production of B. bifidum. There was asymbiosis among B. bifidum, L. acidophilus and Str. thermophilus in mixed culture which resulted in higher viable cell numbers and acid production. The optimum production of yoghurt was achieved by incubation at $37^{\circ}C$ for 8 hours with 5% mixed starter culture (B. bifidum+L.acidophilus+Str. thermophilus). In this case the effective ratio of B. bifidum: L. acidophilus: Str. thermophilus was 2:1:1 on both acid production and viable cell counts.

• Korean Journal of Construction Engineering and Management
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• v.7 no.5
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• pp.94-104
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• 2006

The changed Korean government law associated with the public apartment housing supply, so called the $^{\circ}{\AE}$Apartment Sales Price $Cap^{\circ}{\phi}$, requires new system for estimating construction cost in order to set appropriate price. A model apartment project was carefully designed and its construction cost were analyzed in many different ways. Based on the analyses outcomes, 1,028,000 Won/m2 (excluding cost for underground parking lot) is the most appropriate Price Cap for a smaller than $85{\beta}{\geq}$ apartment unit. Further, it was revealed that the price have to be adjusted reflecting such factors as underground size; structural system; external complex quality; and consumer preferences. Findings from this study will enable the Korean government to realize faster and better application of the related laws. The methodology for obtaining appropriate apartment construction cost will also benefit for future researchers.