• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.474-476
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• 2009

In the radio communication, such as echo cancellation and channel equalization, adaptive filtering is very practical. Its convergence behavior that is used for updating the weights depends on the correlation of the input signal and length of adaptive filter. Highly correlated input and long length of adaptive filter deteriorate the convergence behavior. To solve this problem, recently, subband affine projection algorithm which pre-whiten the correlation of the input and update the weights in subband structure has been presented. This paper presents convergence analysis method of multiple constrained subband affine projection algorithm.

• Journal of Korea Multimedia Society
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• v.24 no.3
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• pp.396-405
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• 2021

In surgery to remove pancreatic cancer, it is important to figure out the shape of a patient's pancreas. However, previous studies have a limit to detect a pancreas automatically in abdominal CT images, because the pancreas varies in shape, size and location by patient. Therefore, in this paper, we propose a method of learning various shapes of pancreas according to the patients and adjacent slices using Faster R-CNN based on Inception V2, and automatically detecting the pancreas from abdominal CT images. Model training and testing were performed using the NIH Pancreas-CT Dataset, and intensity normalization was applied to all data to improve pancreatic detection accuracy. Additionally, according to the shape of the pancreas, the test dataset was classified into top, middle, and bottom slices to evaluate the model's performance on each data. The results show that the top data's mAP@.50IoU achieved 91.7% and the bottom data's mAP@.50IoU achieved 95.4%, and the highest performance was the middle data's mAP@.50IoU, 98.5%. Thus, we have confirmed that the model can accurately detect the pancreas in CT images.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.681-684
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• 2011

최근 IEEE 802.11 WLAN(Wireless Local Area Network)에서 실시간 멀티미디어 서비스가 증가하고 있다. WLAN 의 패킷 전송방식은 Unicast 또는 Broadcast 방식이 있다. Unicast 방식은 재전송을 포함하여 유실율이 적으나 사용자가 증가할수록 AP 에서 필요한 무선 자원의 크기가 증가한다. 무선 자원의 크기가 증가하면 AP 부하가 증가하여 서비스 수용에 한계가 있다. Broadcast 방식은 사용자 수에 상관 없이 무선 자원의 크기가 일정하나, 패킷 유실율이 높다. 본 논문에서는 이러한 문제점을 해결하기 위해 Broadcast 와 FEC(Forward Error Correction) Erasure Code 기반 기술을 적용하는 것을 제안한다. 방송 패킷을 이용 AP 의 부하를 줄이고, Reed Solomon Erasure Code 를 적용하여 패킷 유실 복구율을 높인다. 이러한 방법을 통하여 다수의 사용자에게 안정적인 실시간 멀티미디어 방송 서비스를 제공 할 수 있다. 제안한 방법을 검증하기 위해 Android Platform 에서 FEC 적용 유무에 따른 수신율을 측정하였다. 그 결과 유실율 30%미만인 Broadcast 환경에서 96.4% 이상의 수신율을 보였다.

• Food Science of Animal Resources
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• v.34 no.5
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• pp.614-621
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• 2014

This study was conducted to isolate and characterize bacteriocin-producing bacteria against Clostridium perfringens (C. perfringens) from domestic animals to determine their usefulness as probiotics. Bacteriocin-producing bacteria were isolated from pig feces by the spot-on-lawn method. A total of 1,370 bacterial stains were isolated, and six were tentatively selected after identifying the inhibitory activity against the pathogenic indicator C. perfringens KCTC 3269 and KCTC 5100. The selected strains were identified as Enterococcus faecalis (E. faecalis) by 16s rRNA sequencing. Most of the isolated bacterial strains were resistant to 0.5% bile salts for 48 h and remained viable after 2 h at pH 3.0. Some E. faecalis also showed strong inhibitory activity against Listeria monocytogenes KCTC 3569, KCTC 3586 and KCTC 3710. In the present study, we finally selected E. faecalis AP 216 and AP 45 strain based on probiotic selection criteria such as antimicrobial activity against C. perfringens and tolerance to acid and bile salts. The bacteriocins of E. faecalis AP 216 and AP 45 strains were highly thermostable, showing anticlostridial activities even after incubation at $121^{\circ}C$ for 15 min. These bacteriocin-producing bacteria and/or bacteriocins could be used in feed manufacturing as probiotics as an alternative to antibiotics in the livestock industry.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.12C
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• pp.1258-1267
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• 2003

As the need for stable and high speed wireless Internet service Brows, the wireless LAN service provider hurries to preempt wireless LAN service market. IAPP(InterAccess Point protocol) is defined to be able to provide a secure handoff mechanism of wireless LAN terminal information between AP(Access Point)s, and the related IEEE standard is IEEE 802.11f. For the secure handoff of wireless LAN terminal, it is necessary to transfer terminal's authentication & accounting information securely from old AP to new AP IEEE 802.11f recommends RADIUS server as IAPP server which authenticates AP and provides information for secure channel between APs. This paper proposes IAPP server using Diameter protocol to overcome the limit of RADIUS sewer, and describes about the interaction between server components and integration method with the current IAPP client system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.2
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• pp.164-172
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• 2014

Recently, as the number of IoT (Internet of Things) devices for personal or home intelligence increases, the need for unified control and cooperative utilization is required. This paper presents a novel idea, proposes methods for virtualizing Internet of Things (IoT) devices and hosting them on the home AP instead of relying on a cloud service or purchasing a new device to do so. For this, the process and profile of the IoT gadgets need to be virtualized into JavaScript-based objects. Then, to execute and control the instances of the virtualized IoT objects on the wireless AP, a novel instance management method and their interfaces are designed. The implementation and performance section demonstrates the proposed system's stability and operability by showing the stress test results while the wireless AP is running for its wireless routing.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.88-91
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• 2005

The combustion characteristics of high burning HTPB/AP solid propellants have been investigated by means of a closed bomb method of interval volume of 200 co and 700 cc at pressures from 1000 to 30,000 psi. The burning rate data measured by closed bomb are in good agreement with strand burner test results at pressure from 1000 to 5000 psi using disc sample of 1 mm thickness. The burning rate dat by using 200 cc closed bomb are in general agreement with that of 700 cc closed bomb. At pressure between $5,000\sim7,000$ psi, a market increase in pressure dependence of the linear burning rate occurs for HTPB/AP propellant.

• Journal of Advanced Navigation Technology
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• v.19 no.6
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• pp.564-573
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• 2015

GPS is the representative positioning technology for providing the location information. This technique has the disadvantage that does not operate in the shadow areas, such as urban or dense forest and the interior. This paper proposes a hybrid indoor positioning algorithm, which estimates a more accurate location of the terminal using strength of the Wi-Fi signal from the indoor AP. To determine the location of the user, we establish the most appropriate path loss model for the measurement environment. by using the RSSI value measured in a variety of environment such as building structure, person, distance, etc. The path loss exponent obtained by the path loss model is changed according to the environment. REKF, PF estimate the position of the terminal by using measured value from the AP with path loss exponent. For more accurate position estimation, we select positioning system by the value of threshold measured by experiments rather than a single positioning system. Experimental results using the proposed hybrid algorithm show that the performance is improved by about 17% than the conventional single positioning method.

• Physical Therapy Korea
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• v.27 no.4
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• pp.292-297
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• 2020

Background: Ankle sprain is one of the most common musculoskeletal injuries in the sports population or during usual daily life activities. The sprain can cause functional ankle instability (FAI), and it is very important to treat FAI. However, the optimum intervention method for FAI has yet to be determined. Objects: This study investigated the impact that virtual reality (VR) training program on balance with ankle kinesio taping for FAI. Methods: Twenty-two people were selected for the study and randomly divided into the experimental (n = 11) and the control group (n = 11). The experimental group had attached kinesio taping on the ankle and then implemented a virtual reality exercise program for 30 minutes a day. Nintendo Wii Fit Plus was used for the VR intervention three times a week for four weeks. The control group performed only two measurements without intervention. Results: There were no statistically significant differences in overall, anterior-posterior (AP), medial-lateral (ML) index of the static balance, and significant differences in overall, AP, ML index of the dynamic balance when taping and VR exercise were applied at the same time (p < 0.05). There were no significant differences in overall and ML index of static and dynamic balance compared with before and after assessment between the experimental and the control group, and found differences in AP index of static and dynamic balance (p < 0.05). Conclusion: Kinesio taping may not influence the balance of FAI as great as people expected. VR approach does not affect the static balance of FAI, but it influences dynamic balance in overall, AP, ML index. The authors suggest that VR-based exercises can be used as an additional concept in clinicians for FAI or as part of a home program because the exercises still have limitations.

• Journal of Software Engineering Society
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• v.29 no.1
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• pp.13-21
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• 2020

As CNN model is applied to various domains such as image classification and object detection, the performance of CNN model which is used to safety critical system like autonomous vehicles should be reliable. To evaluate that CNN model can sustain the performance in various environments, we developed an image data augmentation apparatus which generates images that is changed background. If an image which contains object is entered into the apparatus, it extracts an object image from the entered image and generate s composed images by synthesizing the object image with collected background images. A s a method to evaluate a CNN model, the apparatus generate s new test images from original test images, and we evaluate the CNN model by the new test image. As a case study, we generated new test images from Pascal VOC2007 and evaluated a YOLOv3 model with the new images. As a result, it was detected that mAP of new test images is almost 0.11 lower than mAP of the original test images.