• Archives of Reconstructive Microsurgery
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• 제17권2호
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• pp.101-107
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• 2008

Purpose: Free flaps from the great toe are an established method for reconstruction of absent or partially amputated thumbs. However, options differ as to which technique represents the ideal solution for each level of amputation. Various methods of distal thumb reconstruction have been proposed. We prefer to transplant the entire great toe nail complex with the almost all of the pulp rather than a portion of the nail. This paper reflects our experience in using the great toe mini wrap-around flap for distal thumb reconstruction. Materials and Methods: In the period from October of 2005 to July of 2007, 9 patients were treated for traumatic thumb defects localized at the distal phalanx of the thumb. The patients included seven men and two women. The mean age was 44 years (range, 21~60) and the dominant right hand was involved in seven of nine patients. Results: The transferred flaps have survived completely in all cases. The mean range of motion in the interphalangeal joints was 51o, with 73% of the normal uninjured opposite hands. The two-point discrimination was 10.5 mm (range, 5~13 mm). In Semmes-Weinstein monofilament test, the sensibility was 4.31 in 4 cases, 3.61 in 3 cases and 2.83 in 2 cases. The pinch power was 64% (range, 55~95%) of the opposite hand. All patients were satisfied with the appearance of the reconstructed thumb and felt comfortable at final follow-up. Conclusion: We have successfully reconstructed 9 cases of traumatic distal thumb defects using the mini wrap-around free flap. The mini wrap-around free flap in great toe is an excellent alternative method for distal thumb reconstruction in selected patients.

• Archives of Reconstructive Microsurgery
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• 제13권1호
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• pp.63-67
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• 2004

Because traumatic tissue damage on hands and feet often lead to loss of function, permanent deformity, prompt and adequate reconstruction is essential. For children, future growth, as well as function and esthetics, must be taken into account. Several techniques have been employed to reconstruct hand and foot dorsum defects of children. However, skin graft and muscle free flap with skin graft cannot prevent contracture and will interfere with normal growth. Fasciocutaneous free flap reduces contracture and enables early physical therapy, decreasing the need for additional surgical intervention. Parascapular flap is particularly suitable because it has reliable pedicle and is relatively thin. There is little functional loss in the donor site, and also simultaneous extensor tendon reconstruction of hand and foot is possible. The disadvantage of this technique is that postoperative defatting is needed to adjust volume. Our department has achieved satisfactory results using this approach, and would like to report 13 cases of hand and foot reconstruction using parascapular flap in patients under the age of 15 (from March, 1998 to May, 2003).

• KIEE International Transactions on Power Engineering
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• 제4A권4호
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• pp.171-177
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• 2004

In the current age of the information oriented society in which we live, many people use PCs and are dependant on the databases provided by the network server. However, online data can be missed during the occurrence of a blackout and furthermore, power failure can greatly effect Power Quality. This has resulted in the trend of using interruption-free live-line work when trouble occurs in a power system. However, 83% of the population receives an electric shock experience when a laborer is performing interruption-free live-line work. In the interruption-free method, education and training problems have been pinpointed. However, there are few instructors to implement the necessary training. Furthermore, the trainees undergo only a short training period of just 4 weeks. In this paper, to develop a method with no restrictions on time and place and to ensure a reduction in the misuse of materials, immersion type virtual reality (or environment) technology is used. The users of a 3D immersion type VR training system can interact with the system by performing the equivalent action in a safe environment. Thus, it can be valuable to apply this training system to such dangerous work as 'Interruption-free live-line work exchanging COS (Cut-Out-Switch)'. In this program, the user carries out work according to instructions displayed through the window and speaker and cannot perform other tasks until each part of the task is completed in the proper sequence. The workers using this system can utilize their hands and viewpoint movement since they are in a real environment but the trainee cannot use all parts and senses of a real body with the current VR technology. Despite these weak points, when we consider the trends of improvement in electrical devices and communication technology, we can say that 3D graphic VR application has high potentiality.

• 한국안전학회지
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• 제11권1호
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• pp.133-141
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• 1996

In spite of a tendency automatizing manaufacturing processes, since power presses are highly repetitive at high speeds, they have still been using to a large extent in many industries. More often than not, press workers have to make decisions whether work materials are located well or not, they should rearrange them or not, and their bodies would be safe or not. If the decision would be wrong, of course, they cause severe damages to human workers so that many workers haven't been willing to work with them. However, with the help of computer technologies, it would be possible to aid the press workers' decisions, and to allow or prohibit them from inserting their hands between slide rams and dies. Thus, this research was aimed to evaluate and analyze possibilities of applying Image Processing Techniques for prevention of press accidents. Through a series of procedures including Capturing work sites and material, Image Enhancement, Contouring, and Edge Finding, work characteristics were obtained and analyzed. The results showed that there were somewhat differences in image characteristics between accident-induced work scenes and accident-free ones. Consequently, if the image analyses are well carried out in real time, they would give a successful help to human press workers.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 춘계종합학술대회 A
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• pp.784-788
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• 2008

In this research, we propose a remote speech input unit, a new method of user-friendly speech input in speech recognition system. We focused the user friendliness on hands-free and microphone independence in speech recognition applications. Our module adopts two algorithms, the automatic speech detection and speech enhancement based on the microphone array-based beamforming method. In the performance evaluation of speech detection, within-200msec accuracy with respect to the manually detected positions is about 97percent under the noise environments of 25dB of the SNR. The microphone array-based speech enhancement using the delay-and-sum beamforming algorithm shows about 6dB of maximum SNR gain over a single microphone and more than 12% of error reduction rate in speech recognition.

• The Journal of the Acoustical Society of Korea
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• 제17권2E호
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• pp.3-9
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• 1998

Since the introduction of hands-free phone set and teleconferencing system, acoustic echo cancellation has been a challenge for engineers. Recently many researches have shown that the best solution for the acoustic echo compensation problem is represented by an adaptive filter which iteratively tries to identify the unknown impulse response of the system from loudspeaker to microphone. In this paper, we apply the delayless subband adaptive filters and fast affine projection algorithm for the identification of room impulse response. Simulation results show 3∼8 dB more enhanced performance than conventional fullband adaptive filters or subband adaptive filters. In addition, fast affine projection algorithm shows better convergence speed at the expense of the low computational complexity than conventional LMS algorithm.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 제13회 신호처리 합동 학술대회 논문집
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• pp.19-22
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• 2000

최근 이동전화의 사용이 급격히 확산됨에 따라 핸즈프리 단말기를 이용한 전화통신의 필요성이 대두되고 있다. 차량내 핸즈프리 통신상황의 경우 근거리에 위치한 스피커와 마이크로폰의 커플링에 의해 발생하는 음향반향과 차량내에 존재하는 배경잡음은 통화 품질을 크게 저하시킨다. 본 논문에서는 이동통신에 적합한 음향반향제거기와 잡음제거기의 결합시스템을 제안하고, 이를 고정 소수점 DSP를 이용하여 실시간 구현하였다. 실시간 구현을 위하여 음향반향제거기에는 NLMS 알고리즘에 의해 구동되는 제한된 차수의 적응반향제거기법을 사용하였다. 잔여반향 및 배경잡음제거를 위해 CDMA방식의 셀룰라 이동통신에 사용되는IS-127 EVRC음성 부호화기의 표준안에 포함된 잡음제거방식을 사용하였다. 제안된 시스템을 16 비트 고정소수점DSP인 OAK DSP Core를 이용하여 약 18.6MIPS의 연산량으로 실시간 구현되었다.

• 전기학회논문지
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• 제56권3호
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• pp.629-631
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• 2007

In hands-free full-duplex communication systems, acoustic signals picked up by the microphones can be mixed with echo signals as well as noises, which may result in poor performance of the corresponding communication system. Also, the system performance may decrease further if the reverberation occurs since it is harder to estimate the impulse response of the demixing system. For blind source separation (BSS) in such cases, a time-frequency masking approach can be employed to separate undesired echo signals and noises, but, permutation ambiguities also should be solved for the echo cancellation. In this paper, we propose a new acoustic echo cancellation (AEC) approach utilizing the time-frequency masking and higher-order statistics, whereby a desired signal selection, based on coherence and third-order statistics (i.e., kurtosis), is introduced along with output signal normalization. Simulation results demonstrate that the proposed approach yields better echo and noise cancellation performances than the conventional AEC approaches.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
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• pp.416-418
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• 2006

In this paper, a new acoustic echo cancellation approach based on the DUET algorithm and scaling factor estimation is proposed to solve the scaling ambiguity in case of blind separation based acoustic echo cancellation in a noisy environment. In hands-free full-duplex communication system. acoustic noises picked up by the microphone are mixed with echo signal. For this reason, the echo cancellation system may provide poor performance. For that purpose, a degenerate unmixing estimation technique, adjusted in the time-frequency domain, is employed to separate undesired echo signals and noises. Also, since scaling and permutation ambiguities have not been solved in the blind source separation algorithm, kurtosis for the desired signal selection and a scaling factor estimation algorithm are utilized in this rarer for the separation of an echo signal. Simulation results demonstrate that the proposed approach yields better echo cancellation and noise reduction performances, compared with conventional methods.

• Journal of Chest Surgery
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• 제10권1호
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• pp.53-58
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• 1977

There are many procedures which treat pulmonary tuberculosis. Pneumoperitoneum of those which was begun by Banyai in 1934 is considered effective collapse therapy economically and socially in Korea. The author had studied 30 patients receiving pneumoperitoneum and/or chemotherapy who were moderatedly advanced pulmonary tuberculosis with positive sputum to AFB stain between Apt. 1, 1976 and Oct. 1, 1976. An attempt is to clarify the effects of pneumoperitoneum with chemotherapy [A group: 20 patients] in contrast with chemotherapy alone [B group: 10 patients] for 6 months. The results obtained were as follows: 1] All both groups showed the diminished pulmonary cavity size, but the effect of A group is prominent as 74% rather than 39% of B group. 2] Sputum conversion ratio is 55% in A group, and 20% in B group. 3] In Korea, the moderate amount of air is 1500cc in men, 1000cc in women. 4] Although pneumoperitoneum is in old hands, it is a relatively safe procedure, well tolerated, free from serious complications. 5] The advantages of pneumoperitoneum are evident in the treatment of bilateral lesion, with or without cavity, not too far advanced.