• Journal of the Institute of Electronics Engineers of Korea SC
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• 제46권3호
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• pp.52-58
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• 2009

If a moving target has a linear characteristics, the Kalman filter can estimate relatively accurate the location of a target, but this performance depends on how the dynamic status characteristics of the target is accurately modeled. In many practical problems of tracking a maneuvering target, a simple kinematic model can fairly accurately describe the target dynamics for a wide class of maneuvers. However, since the target can exhibit a wide range of dynamic characteristics, no fixed SKF(Simple Kalman filter) can be matched to estimate, to the required accuracy, the states of the target for every specific maneuver. In this paper, a new AKF(Active Kalman filter) is proposed to solve this problem The process noise covariance level of the Kalman filter is adjusted at each time step according to the study result which uses the neural network algorithm. It is demonstrated by means of a computer simulation that the tracking capability of the proposed AKF(Active Kalman filter) is better than that of the SKF(Simple Kalman Filter).

• The Journal of Korean Medicine
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• 제30권5호
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• pp.88-101
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• 2009

Objectives: Since Korean traditional medicine has an integrative perspective by its nature, the patients' psychological and physical problems in a Korean traditional clinic may be resolved through a more integrative approach. The purpose of this study was to describe the latent characteristics of psychological health of child outpatients and their parents visiting Korean traditional clinic with physical complaints and was to propose an alternative curriculum to meet their needs based on their psychological and physical aspects. Methods: Subjects studied consisted of 100 outpatients (59 boys, 41 girls, mean age 55 months, age range 18 to 83 months) and their parents. Behavior characteristics for children were measured by Korean version of Child Behavior Checklist for Ages 1.5-5 (CBCL1.5-5) while parenting stress, depression, and anxiety for parent were measured by Korean-Parenting Stress Index-Short Form (K-PSI-SF), Center for Epidemiologic Studies Depression Scale (CES-D) and State-Trait Anxiety Inventory (STAI), respectively. The data of subjects were compared to those of standardized groups and then were compared according to child's gender within sample. Results: Child participants were reported to have significantly higher scores of all CBCL 1.5-5 subscales than the standardized group. When compared, no differences of K-PSI-SF, CES-D, and STAI was found between parents of participants and the standardized groups. However, parents of child participants with at-risk psychological problems showed significantly higher scores of all parenting stress subscales than those of all child participants. In addition, the mothers of boy participants demonstrated significantly higher anxiety, depression and parenting stress than those of girl participants irrespective of psychological severity. Conclusions: We discussed the implication of these results in clinical situation and make recommendations for curriculum of psychiatry and pediatrics with the aim of improving proper diagnosis, consulting and treatment.

• Journal of Distribution Science
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• 제7권2호
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• pp.89-119
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• 2009

The purpose of this research is showing an appropriate way of maximizing customer service and establishing VOC system by analyzing different voices from complaining customers as well as loyal customers. This research is also aimed at figuring out how companies can implement effective service marketing methods in the field complying with customers' needs and how they can survive in the competition. The range of research is confined to 5 marketing companies and their web-sites on which customers can get logged and directly post their claims. These web-sites showed how those 5 companies cope with customer claims. A questionnaire research was made in A's store to evaluate customer satisfaction. These are conclusions drawn by this research. First, prompt reactions of sincerity to customers' claims contribute to building favorable corporate images. Second, the preference to VOC channels varies with age and sex. Marketers should implement respectively different channels for customers under age 30 and those over age 40. Women have a tendency to prefer instant phone conversations and want to have their claims well listened to. Third, a series of shift in customer trend drives companies into establishing their own interactive VOC systems based on customers' preferences. Customer-oriented management has become a key factor for survival in recent intensely competitive market situation, as the web-based e-commerce market has been rapidly growing accompanied with a dramatic advance of network marketing methods. This research suggests some practical methods to establish a customer-oriented VOC system that can be easily adopted in the field.

• The KIPS Transactions:PartA
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• 제12A권5호
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• pp.341-354
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• 2005

The main bottleneck for large scale VOD systems is bandwidth of storage or network I/O due to the large number of client requests simultaneously, and then efficient techniques are required to solve the bottleneck problem of the VOD system. Patching is one of the most efficient techniques to overcome the bottleneck of the VOD system through the use of multicast scheme. In this paper, we propose a new patching scheme, called P2P proxy patching, for improving the typical patching technique by jointly using the prefix caching and P2P proxy. In our proposed scheme, each client plays a role in a proxy to multicast a regular stream to other clients that request the same video stream. Due to the use of the P2P proxy and the prefix caching, the client requests that ive out of the patching window range can receive the regular stream from other clients in the previous patching group without allocating the new regular channels from the VOD server to the clients. In the performance study, we show that our patching scheme can reduce the server bandwidth requirement about $33\%$ less than that of the existing patching technique with respect to prefix size and request interval.

• The KIPS Transactions:PartC
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• 제17C권1호
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• pp.15-26
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• 2010

Social Networks such as 'Facebook' and 'Myspace' are regarded as useful tools for people to share interests and maintain or expand relationships with other people. However, they pose the risk that personal information can be exposed to other people without explicit permission from the information owner. Therefore, we need a solution for this problem. Although existing social network sites allow users to specify the exposing range or users who can access their personal information, this cannot be a practical solution because the information can still be revealed to third parties through the permitted users albeit unintentionally. Usually, people allow the access of unknown person to personal data in online social networks and this implies the possibility of information leakage. We could use an access control method based on trust value, but this has the limitation that it cannot reflect the quantitative risk of information leakage. As a solution to this problem, this paper proposes an access control method based on a synthesized metric from trust and risk factors. Our various experiments show that the risk of information leakage can play an important role in the access control of online social networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제37C권11호
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• pp.1138-1147
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• 2012

In this paper, an efficient power control based MF-TDMA resource allocation scheme is proposed for next generation military satellite communication systems. The proposed scheme has the flexibility is used to support heterogeneous terminals with differ in transmission capabilities. The method can be divided into two parts : burst size calculation and burst structure determination. At first, we estimate the link budget taken into account a dynamic satellite link state variation. Then, applicable ACM level and burst size is chosen. In burst structure determination phase, we reorganize the burst structure in time-frequency domain by controlling limited power, bandwidth, time resources. In particular, we compensate the power spectral density among different terminals to integrate them in same transponder, Furthermore, we increase the packing efficiency by controlling the ACM level of the burst in applicable power spectral density range. Simulation results show that the method increase the spectral efficiency and burst packing efficiency. In addition, slot allocation rejection ratio is successfully reduced.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제20권12호
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• pp.546-554
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• 2019

Typically, closed-circuit television (CCTV) monitoring is mainly used for post-processes (i.e. to provide evidence after an incident has occurred), but by using a streaming video feed, machine-based learning, and advanced image recognition techniques, current technology can be extended to respond to crimes or reports of missing persons in real time. The multi-CCTV cooperation technique developed in this study is a program model that delivers similarity information about a suspect (or moving object) extracted via CCTV at one location and sent to a monitoring agent to track the selected suspect or object when he, she, or it moves out of range to another CCTV camera. To improve the operating efficiency of local government CCTV control centers, we describe here the partial automation of a CCTV control system that currently relies upon monitoring by human agents. We envisage an integrated crime prevention service, which incorporates the cooperative CCTV network suggested in this study and that can easily be experienced by citizens in ways such as determining a precise individual location in real time and providing a crime prevention service linked to smartphones and/or crime prevention/safety information.

• Ecology and Resilient Infrastructure
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• 제3권2호
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• pp.117-125
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• 2016

Current cities encounter various types of water problems due to rapid urbanization and climate change. The increasing significance of urban water problems calls for the establishment of resilient alternatives to prevent and minimize social loss that results from these phenomena. As a background research for establishing resilient infrastructures for the mitigation of urban water problems, we evaluated the robustness of structural alternatives for urban flood as a representative case. Combining the robustness index (RI) and the cost index (CI), we suggested the robustness-cost index (RCI) as an indicator of the robustness of structural alternatives, and applied the index to assess the existing infrastructures and structural alternatives (i.e., sewer network expansion, additional storage tank construction, and green roof construction) at a site prone to floods located around Gangnam-station, Seoul, Korea. At a rainfall intensity frequency range of 2 to 20 years, the usage of a storage tank and a green roof showed relatively high RCI value, with a variation of an alternative showing greater RCI between the two depending on the size of design rainfall. For a rainfall intensity frequency of 30 years, installing a storage tank with some green roofing was the most resilient alternative based on the RCI value. We proposed strategies for establishing resilient infrastructures for the mitigation of urban floods by evaluating the robustness of existing infrastructures and selecting optimal structural alternatives with the consideration of scales of design disaster.

• Journal of the Korean Vacuum Society
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• 제16권5호
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• pp.371-376
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• 2007

We have investigated the lasing characteristics of the InGaAs quantum dot laser diode (QD-LD) and InGaAs quantum well laser diode (QW-LD) operated at the 980 nm wavelength range. The 980-nm lasers are used as a pumping source for a erbium-doped fiber amplifier (EDFA) and it shows high efficiency in long-haul optical fiber network. We have compared the threshold current density, the characteristic temperature, the optical power and the internal efficiency of QD-LD and QW-LD under a pulsed current condition. The QD-LD shows superior performances to the QW-LD. Further optimization of a LD structure is expected to the superior performances of a QD-LD.

• Korean Journal of Remote Sensing
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• 제31권2호
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• pp.111-125
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• 2015

In this study, the target detection using both high-resolution satellite SAR and Elecro-Optical (EO) images such as TerraSAR-X and WorldView-2 is performed, considering the characteristics of targets. The targets of our interest are featured by being stationary and appearing as cluster targets. After the target detection of SAR image by using Constant False Alarm Rate (CFAR) algorithm, a series of processes is performed in order to reduce false alarms, including pixel clustering, network clustering and coherence analysis. We extend further our algorithm by adopting the fast and effective ellipse detection in EO image using randomized hough transform, which is significantly reducing the number of false alarms. The performance of proposed algorithm has been tested and analyzed on TerraSAR-X SAR and WordView-2 EO images. As a result, the average false alarm for group of targets is 1.8 groups/$64km^2$ and the false alarms of single target range from 0.03 to 0.3 targets/$km^2$. The results show that groups of targets are successfully identified with very low false alarms.