• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1999년도 KOBA 방송기술 워크샵 KOBA Broadcasting Technology Workshop
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• pp.227-232
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• 1999

We have been making researches on 3-D displays using computer-generated holograms(CGHs). Our CGHs are binary Fresnel holograms that reconstruct point light sources and are recorded by using high resolution laser printers (image setters). We use an image setter with a resolution of 5080 dots per inch. It is possible to reconstruct CGHs with light-emitting points. As the resolution of the image setter is not so high, it is better to use a spherical wave as a reference beam. We considered the recordable points objects are restricted by the low resolution, and proposed the multiplex type hologram to reduce the number of point objects recorded in the unit area of the CGH. We proposed a method to make computer-generated color hologram which could reconstruct color point light sources, by combining RGB color filters with the stripe CGHs corresponding to each color. We considered two kinds of gradation method on our binary CGHs. In this paper, we propose a multiple reconstruction method for improving the narrow viewing field.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2008년도 춘계 종합학술대회 논문집
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• pp.15-18
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• 2008

본 논문은 구조 광 영상을 이용하여 3차원 얼굴을 복원하는 방법을 제안한다. 프로젝터와 카메라의 시선벡터가 평행하다고 가정한다. 먼저 격자 형태의 구조 광을 배경에 투영하고 참조 구조 광 영상을 획득한다. 참조 구조 광 영상을 사용하여 카메라와 프로젝터를 보정한다. 이후 사람의 얼굴에 동일한 형태의 구조 광을 투영하고 얼굴 구조 광 영상을 획득한다. 획득한 두 종류의 구조 광 영상에서 추출된 특징 점들의 위치 변화를 측정하고 측정된 변화량으로 3차원 얼굴을 복원 한다. 실험 결과를 보면, 이런 간단한 장치를 통해 사람이 인식할 수 있을 정도의 3차원 얼굴 영상을 얻을 수 있음을 알 수 있다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.479-480
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• 2005

The Analog data is impossible to perfect reconstruct original data at a hologram data storage because of noise such as cross talk. So it is necessary that data can be stored by digital signal unavoidably. Therefore this work deals with experiments from this point of view through writing & reading of digital data. We stored 256bit digital data at one point on As-Ge-Se-S chalcogenide thin film and we reconstruct original data of 100% through the specified algorithm such as the histogram equalization, the interactive correction, etc. This result shows that the data is able to reconstruct under relative low diffraction efficiency. As the result, we expect the possibility of chalcogenide thin film for HDDS as the analysis of the effective resolution refer to reconstruction rate and diffraction efficiency.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권6호
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• pp.1994-2017
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• 2022

In view of the past, the mobility of the multicast source in the mobility networks is seldom discussed in the traditional multicast protocols. It is a heavy cost for the traditional multicast protocols to reconstruct the multicast tree in the Network Mobility (NEMO) environment. This article proposes an alternative multicast protocol, referred to as Mobility-Sensitive Multicast protocol (MSM), for the NEMO environment. The MSM can be considered as an alternative version of the Multicast Listener Discovery (MLD) protocol to maintain the multicast tree in the NEMO. There are two obvious contributions for the MSM. Reconstruct mechanism could rebuild the multicast tree for the mobility of the multicast source. Multi-group suppression mechanism reduce the multicast tree maintaining cost for the mobility of the multicast members. Through the performance evaluations and analyses, the MSM has less cost to maintain the multicast tree than the traditional multicast protocols, especially for a large numbers of multicast groups. Moreover, the MSM allows the mobility of the multicast source to reconstruct the multicast tree easily.

• Archives of Plastic Surgery
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• 제49권6호
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• pp.764-768
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• 2022

The wrap-around flap (WAF) has become a popular approach to thumb reconstruction because the results are functionally and cosmetically excellent. By modifying to a partial toenail transfer, the WAF can also be used for finger reconstruction. However, performing cosmetically superior finger reconstruction is a significant challenge because it is difficult to reconstruct the natural nailfold by partial nail transplantation, although partial nail transplantation is required to reconstruct a narrow fingernail. One side of the reconstructed lateral nailfold tends to be a missing nail margin, and one side of the proximal nailfold angle tends to be retracted. Based on the rationale that loss of the lateral nailfold volume due to the postoperative tension of the volar flap would result in a missing nail margin, the volume of the lateral nailfold was maintained with a single thread that was passed from the nail to the volar flap. Additionally, half of the proximal nailfold from the nail plate was elevated to advance it forward. The results indicated that a cosmetically natural nailfold was achieved with the WAF approach to finger reconstruction. These easy and simple techniques enable reconstruction of a cosmetically natural nailfold using WAF for finger reconstruction.

• 대한두경부종양학회지
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• 제17권2호
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• pp.190-193
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• 2001

Background and Objectives: Reliable and versatile free flap has become a mainstay in reconstruction of the head and neck. But until now pectoralis major myocutaneous flap (PMMCF) as workhorse is useful and has some advantages such as good viability, one-stage reconstruction and carotid protection. The objective of this study was to review the role and indication of PMMCF in this era of potent free flaps for head and neck reconstruction. Patients and Methods: Sixty one PMMCF and one hundred forty six free flaps used for head and neck reconstruction between 1991 and 2001 were reviewed retrospectively. We compared the applied sites of flap, the flap failure rate and complications. Results: Contrary to the free flap, use of PMMCF has gradually decreased after the middle of 1990s. PMMCF were mainly used for mucosal defect(33cases, 54.1%) and cervical skin defect(22cases, 36.1%) and free flap were mainly used for mucosal defect(129cases, 88.4%). In point of use of PMMCF according to years, from 1991 to 1997, 30cases(70%) are used to reconstruct mucosal defect and 12cases(29%) are used to reconstruct skin defect. But from 1998 to 2001, only 2cases(10.5%) are used to reconstruct mucosal defect and 13cases(68.4%) are used to reconstruct neck skin defect. In case of free flap, from 1991 to 1997, 41cases (87%) are used to reconstruct mucosal defect and from 1998 to 2001 88cases(89%) are used as same purpose. Three major necrosis (more than 50%) deveolped in 61 PMMCF (4.9%) and three major necrosis developed in 146 free flaps(2.1%). Conclusion: PMMCF is no longer flap of choice for primary reconstruction but it is a still one of a good tool in some head and neck reconstruction such as covering single wide defect of face or neck skin, back-up procedure of free flap, postoperative status, treatment of pharyngocutaneous fistula and covering vital structure.

• Journal of Mechanical Science and Technology
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• 제14권1호
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• pp.1-10
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• 2000

This work shows that it is possible to obtain information about more than one parameter from acoustic field information. A variety of ultrasonic Lamb wave modes were utilized to reconstruct thickness and density of an isotropic plate. An image reconstruction of one parameter (thickness of a plate) was carried out for four cases, i.e., the lowest symmetrical and anti symmetrical modes, and the fastest symmetrical and anti symmetrical Lamb waves among multiple modes. For two parameter reconstructions (thickness and density), the image processing was performed using the lowest symmetrical and antisymmetrical modes simultaneously. In this work, a modified version of algebraic reconstruction technique (ART), which is a form of finite-series expansion method, was employed to reconstruct the ultrasonically computed tomographic images. Results from several sample geometries are presented.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.497-502
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• 2001

Three-dimensional natural convection from a discrete flush-mounted circular heat source on the bottom of a cubic enclosure was studied by using a holographic interferometric tomography. The heat source was located at the off-center of the bottom plate so that three-dimensional temperature field can be achieved. A set of multidirectional holographic interferogram was recorded by employing a double-reference beam, double-exposure holographic technique in order to eventually reconstruct the temperature fields. The recorded interferometric data appear good enough to be further processed to extract optical pathlength data from them and finally reconstruct the temperature fields. A complete analysis of the temperature fields including the field reconstructions and comparison with thermocouple measurements is underway and will be reported shortly.

• Journal of applied mathematics & informatics
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• 제9권2호
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• pp.607-620
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• 2002

In this paper, we consider the updating problems to reconstruct the biconnected-components and to reconstruct the weighted shortest path in response to the topology change of the network. We propose two distributed algorithms. The first algorithm solves the updating problem that reconstructs the biconnected-components after the several processors and links are added and deleted. Its bit complexity is O((n'+a+d)log n'), its message complexity is O(n'+a+d), the ideal time complexity is O(n'), and the space complexity is O(e long n+e' log n'). The second algorithm solves the updating problem that reconstructs the weighted shortest path. Its message complexity and ideal-time complexity are $O(u^2+a+n')$ respectively.

• 한국컴퓨터산업학회논문지
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• 제5권7호
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• pp.711-720
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• 2004

프로그램을 계산적으로나 수명적으로 최적화하는 기법에는 수식 모션 변환과 수식 모션을 포함하는 배정문 모션 변환이 있다. 본 논문에서는 노드 단위 분석과 명령어 단위 분석의 혼용 때문에 발생하는 모호함을 가지는 Knoop의 알고리즘을 개선하는 불필요한 코드 모션 재구성 알고리즘을 제안하였다. 제안한 알고리즘은 수식이나 배정문의 불필요한 재계산이나 재수행을 피하게 함으로써 프로그램의 능률과 수행시간을 개선하였다.