• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.274-275
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• 2000

This paper introduces new ordering algorithms using the graph of data structure and forward/backward substitution of LU decomposition using recursive function. The performance of the algorithm is compared with Tinney's algorithm using 14 bus systems. Test results show that the new fill-in element of Jacobian matrix using the proposed ordering algorithm is same as that of Tinner scheme 3 and the forward/backward substitution can reduce the computation time

• 한국정보통신설비학회:학술대회논문집
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• 2003.08a
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• pp.229-233
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• 2003

최근, 인터넷 사용자가 급증하면서 빠른 서비스에 대한 문제가 큰 관심이 되고있다. 특히 데이터베이스 시스템에서 저장 삭세 수정 등은 사용자에게 긴 대기시간을 요구할 수도 있기 때문에 사용자의 불평을 야기할 수 있다. 이 논문에서는 3-티어 방식에서 요즘 많이 사용되는 application server의 cache에 대해서 말하고자 한다. 기존 application server는 데이터를 application server cache에 저장하여 같은 데이터를 서비스할 경우 server의 cache를 사용하지만 이 논문에서 제안하는 것은 접속된 client를 관리하여 각각의 client에 cache를 만들고 application server나 또는 데이터베이스 server가 서비스를 하지 못할 경우는 가장 최근의 데이터를 가지고 있는 client를 찾아 client cache에 있는 데이터를 서비스 하자는 것이다.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.08a
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• pp.298-301
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• 1998

HMM 훈련 방법에 따른 음소인식률의 변화에 대하여 기술한다. 음성모델은 이산 확률 밀도 혹은 연속 확률 밀도를 갖는 HMM을 사용하였으며, 훈련 알고리즘으로서는 forward-backward 와 segmental K-means 알고리즘을 사용하였다. 연속 확률 밀도는 N개의 mixture로 구성되어 있는데 1개의 mixture로 확장할 경우에서는 이진 트리 방식과 one-by-one 방식을 사용하였다. 여러 가지의 조합을 이용하여 음소인식 실험을 수행한 결과 연속 확률 분포를 사용하고 one-by-one 방식을 사용한 forward-backward 알고리즘이 가장 우수한 결과를 나타내었다.

• The Journal of the Acoustical Society of Korea
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• v.27 no.1E
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• pp.25-29
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• 2008

The projection approximation subspace tracking (PAST) is one of the attractive subspace tracking algorithms, because it estimatesthe signal subspace adaptively and continuously. Furthermore, the computational complexity is relatively low. However, the algorithm still has room for improvement in the subspace estimation accuracy. In this paper, we propose a new algorithm to improve the subspace estimation accuracy using a normally ordered input vector and a reversely ordered input vector simultaneously.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.6
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• pp.1425-1429
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• 1996

A conventional sequence search algorithm for PRI analysis occurs the harmonic problem under missing pulses. An improved PRI analysis algorithm is proposedto remedy the harmonic problem. After dividing an overall PRI range into subbands withoug harmonic, a sequence search is done into forward and backward in time. The proposed algorithm increases the preformance compared with that of conventional sequence search algorithm.

• Journal of the Korean Society of Physical Medicine
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• v.8 no.3
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• pp.467-477
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• 2013

PURPOSE: The purpose of this study was to identify the effects of backward pedaling ergometer training on ankle ROM, lower extremities strength, foot pressure in hemiplegia. METHODS: The subjects consisted of control group(n=10) and experimental group(n=10), subjects were trained 5 times a week for 2 weeks each group. Control group were trained forward, experimental group were trained backward pedaling with physical therapy in both groups. Each group measured ankle joint ROM with DUALER IQ and ankle and knee joint flexor and extensor muscle strength by Manual Muscle Test System and foot pressure by Gait view system. RESULTS: The result of this study between pre and post test that experimental group had statistically significantly differences in ankle joint range of motion and lower extremities strength. But foot pressure had not statistically significant differences. There was not significantly difference of variation between groups. CONCLUSION: Therefore these results mean that backward and forward pedaling ergometer training effected an improvement of lower extremities function in hemiplegia.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.11
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• pp.74-79
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• 2005

Computational studies on the hydrodynamic behavior of the forward-sweep inducers for the rocket-engine turbopump are presented in comparison with the conventional backward- sweep inducers. In the present study, two kinds of forward-sweep inducers are designed and numerically investigated. Forward-sweep inducers have bigger tip solidity compared to backward-sweep inducers even with shorter axial length due to their forward-sweep leading edge profiles. It is shown that back flows at the inlet decreases dramatically for forward- sweep inducers. And the low pressure region at the back flow are also decreased, which is assumed to promote the suction performance of the inducers. It seems that the hub located upstream of the tip at the leading edge induces pre whirl at the inlet blade tip for the backward sweep inducer. And this pre whirl leads to the big back flow.

• The Journal of the Acoustical Society of Korea
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• v.25 no.3E
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• pp.115-122
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• 2006

The bistatic scattering of an incident wave by a hemi-spherically capped cylinder is of particular interest because it has rarely been studied until the present day. The configuration of a hemi-spherically capped cylinder is similar to naval underwater weapons (submarines, mines, torpedos, etc.), but which is not exactly the same. This paper describes a novel laboratory experiment aimed at direct measurement of bistatic scattering by a hemi-spherically capped cylinder. Bistatic scattering by a hemi-spherically capped cylinder was measured in an acoustic water tank (5m long, 5m wide, 5m deep) using a high frequency projector (120kHz) and hydrophone. Measurements of monostatic scattering were also made under the same conditions. The bistatic scattering pattern by a hemi-spherically capped cylinder was measured against the incident angles $(0^{\circ},\;15^{\circ},\;20^{\circ},\;30^{\circ},\;45^{\circ},\;60^{\circ},\;90^{\circ})$ in order to verify various scattering pattern characteristics by the change of incident angle. The results indicate that the bistatic scattering TS at a wide scattering angle is much stronger than the mono static scattering TS. In bistatic scattering, the forward scattering TS is significantly stronger than the backward scattering TS, and the forward scattering pattern is also broader. In case of seven incident angles, the maximum value of forward scattering TS is about 14dB stronger than that of backward scattering TS. It is also found that forward scattering varies with the incident angle of sound to a much less extent than backscattering, and it is not seriously affected by the incident angle. These features could be the advantages of using forward scattering for detecting underwater targets at long range and increasing detection area and probability.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.3
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• pp.135-144
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• 2021

Purpose : The purpose of this study was to investigate the effect of 2 weeks of backward walking exercise (BWE) on cervical angle and gait parameters in college students with forward head posture. Methods : Fifteen subjects participated in the experiment. All the participants had a craniovertebral angle (CVA) of 55 degrees or less. The purpose of the study was explained to all the subjects prior to participation, and volunteered to take part in the study. A camera capable of taking pictures of the lateral plane was installed at a distance of 1.5 meters from each subject. Images of forward head posture were obtained before and after performing the BWE, and the CVA and craniorotational angle (CRA) were compared pre- versus post exercise. Foot pressure and gait parameters (step length of left and right, stride length, stance of left and right, swing of left and right, step time of left and right, and stride time) were measured using a rehabilitation treadmill. The subjects performed the BWE for 2 weeks. The exercise program consisted of a 5-minute warm-up exercise, 20-minute main exercise, and 5-minute cool-down exercise. In the main exercise, the treadmill speed was set to 2.4 km/h in the first week and 3.4 km/h in the second week. A paired t test was used to compare the CVA and CRA and gait parameters before and after the exercise. Results : Comparison of the CVA and CRA before and after the BWE revealed a significant difference post exercise, with a marked improvement in forward head posture after the exercise (p<.05). Conclusion : Based on the results of this study, the BWE is considered to be an effective exercise for the forward head posture. Also, additional research is needed to shed light on the impact of the BWE on gait parameters.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.22 no.2
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• pp.315-327
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• 1992

The purpose of this study was to evaluate the utilization of the orthopantomograph as a diagnostic aid to observe maxillary sinus and adjacent structures. For achieving this goal. the lead plates were attached to the five walls of the maxillary sinus of a human dry skull. The dry skull was placed in fourteen different positions; standard. 20mm forward. 20mm backward. 10 degree upward. 10 degree downward. 20mm lateral. forward & upward, forward & downward. forward & lateral. backward & upward. backward & downward, backward & lateral. upward & lateral. downward & lateral position. The obtained results were as follows: 1. The image of the medial wall was observed very differently according to the head positions. 2. The image of the anterior wall was observed at medial third to half of the maxillary sinus in each head position. 3. the image of the posterior wall was always observed at lateral third of the maxillary sinus in all head positions and more obviously in the downward-lateral position. 4. The image of the superior wall was observed at the inferior third to half of the orbit in each head position. 5. The image of the inferior wall was always observed at the inferior third of maxillary sinus in all head positions and observed more obviously in the standard and downward-lateral positions. 6. The images of the zygomatic process. zygomatic arch and zygomaticotemporal suture were observed very well in the downward-lateral position.