• 한국CDE학회논문집
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• 제16권4호
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• pp.277-284
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• 2011

In tangible augmented reality (AR) environments for virtual prototyping, the user interacts with virtual products by manipulating tangible objects with his or her hands, but the user often encounter awkward situations in which his or her hands are occluded by augmented virtual objects, which reduces both immersion and ease of interaction. In this paper, we present how to resolve such hand region occlusion in order to enhance natural interaction and immersive visualization. In the AR environment considered, we use two types (product-type and pointer-type) of tangible objects for tangible user interaction with a virtual product of interest. Holding the tangible objects with his or her hands, the user can create input events by touching specified regions of the product-type tangible object with the pointer-type tangible object. We developed a method for resolving hand region occlusion frequently arising during such user interaction, It first detect hand region in a real image and refines the rendered image of the virtual object by subtracting the hand region from the rendered image, Then, it superimposes the refined image onto the real image to obtain an image in which the occlusion is resolved. Incorporated into tangible AR interaction for virtual prototyping of handheld products such as cellular phones and MP3 players, the method has been found by a preliminary user study that it is not only useful to improve natural interaction and immersive visualization of virtual products, but also helpful for making the users experience the products' shapes and functions better.

• 한국콘텐츠학회논문지
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• 제18권3호
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• pp.11-18
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• 2018

몰입 가상현실 환경에서 가상 객체들을 선택하고 조작하기 위해서는 사용자가 원하는 가상 객체를 빠르고 정확하게 선택할 수 있어야 한다. 가상현실에서 객체 선택을 위한 가장 알려진 접근 방법은 Ray-casting 방법이다. Ray-casting은 가상현실 환경에서 사용자의 손이나 시야 방향에서 직선으로 이동하는 가상의 선을 발사하고, 이 가상의 선이 발사되는 과정에서 충돌되는 가상 객체를 사용자가 선택할 수 있게 해주는 방법이다. 하지만, 가상 객체들이 겹쳐져 있는 상황에서는 사용자가 원하는 객체가 아닌 다른 객체들이 선택 될 수 있는 모호성 문제가 발생하게 된다. 이러한 방법을 해결하기 위해서 본 논문에서는 겹쳐진 가상 객체들 중 사용자가 원하는 객체를 선택하고자 하는 경우, 사용자가 겹쳐진 객체들의 그룹을 먼저 선택하게 한 후에 이 겹쳐진 객체들이 가지고 있는 기하학적인 연관관계를 계산하고 이를 사용자의 시점에서 겹쳐지지 않게 펼쳐서 시각화를 하는 Explosion-casting 방법을 제안한다. 제안한 방법의 평가를 위해서 기존의 Ray-casting 방법과 비교를 하였을 때, 겹쳐져 있는 가상 객체를 선택할 때 걸리는 속도와 정확도가 증가하는 결과를 보여주었다.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.305.1-305.1
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• 2002

The temporal profiles of the changes of dopaminergic cell and microglial activation induced by transient cerebral ischemia was investigated in the substantia nigral region which lay outside ischemic areas of rat brain after middle cerebral artery occlusion (MCAO). Transient cerebral ischemia was induced by intraluminal occlusion of the right middle cerebral artery for 2 hand reperfusion was continued for 1, 2. 3. 7. 10. 14. 30, 60. and 120 days. Activated microglial cells were visualized with immunohistochmistry using OX-43 antibody. (omitted)

• Maxillofacial Plastic and Reconstructive Surgery
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• 제39권
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• pp.16.1-16.6
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• 2017

Background: Mandibular reconstruction is performed after segmental mandibulectomy, and precise repositioning of the condylar head in the temporomandibular fossa is essential for maintaining preoperative occlusion. Methods: In cases without involvement of soft tissue around the mandibular bone, the autopolymer resin in a soft state is pressed against the lower border of the mandible and buccal and lingual sides of the 3D model on the excised side. After hardening, it is shaved with a carbide bar to make the proximal and distal parts parallel to the resected surface in order to determine the direction of mandibular resection. On the other hand, in cases that require resection of soft tissue around the mandible such as cases of a malignant tumor, right and left mandibular rami of the 3D model are connected with the autopolymer resin to keep the preoperative position between proximal and distal segments before surgical simulation. The device is made to fit the lower border of the anterior mandible and the posterior border of the mandibular ramus. The device has a U-shaped handle so that adaptation of the device will not interfere with the soft tissue to be removed and has holes to be fixed on the mandible with screws. Results: We successfully performed the planned accurate segmental mandibulectomy and the precise repositioning of the condylar head by the device. Conclusions: The present technique and device that we developed proved to be simple and useful for restoring the preoperative condylar head positioning in the temporomandibular fossa and the precise resection of the mandible.

• 대한한방내과학회지
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• 제27권1호
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• pp.288-293
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• 2006

Background : Monoplegia is the paralysis of a limb. It is commonly caused by an injury to the cerebral cortex, and rarely caused by injury to the internal capsule, brain stem, or spinal cord. Most problems with cerebral cortex is derived from the occlusion of a brain cortex blood vessel due to thrombus or embolus. Objectives : This study is to see if there is a significance in thermal differences of acupoints in diagnosis and treatment of monoplegia on an upper extremity to test the validity of acupuncture and herbal treatment for it. Methods : By using Digital Infrared Thermographic Imaging(DITI), thermal differences$({\Delta}T)$ of acupoints on the upper extremity in a patient with monoplegia on the right upper extremity were measured after an attack of the disease. By giving Mangeum-tang(萬金湯) and treating the patient with acupuncture. the temperature changes of the upper extremity were examined through DITI and improvement was observed. Results : Compared with the left arm which suffered no such injury, the right recovered about 80% of sensation, and the grade of monoplegia improved from Grade O to Grade V. Also, the temperatures of right palmar-dorsal hand and the region of Weiguan(外關, Waiguan, TE5) were $1^{\circ}C$ and $1.45^{\circ}C$ higher than the same left region on admission day, but the thermal differences$({\Delta}T)$ narrowed to $0.5^{\circ}C$ by the last day. Conclusions : Results suggest that DITI screening is a reliable method of prognosis and that the time required for treatment can be estimated through this method in cases of monoplegia to an upper extremity. Also, progress in treatment is reflected in thermal differences of acupoints of the monoplegic upper extremity in accordance with the theory of meridian. This supports a role for acupuncture and herbal treatment for monoplegia.

• 대한치과교정학회지
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• 제25권3호
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• pp.355-373
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• 1995

두개악안면 영역은 많은 해부학적 구조를 포함하는 근골격구조(musculodentos keletal system)로 두부골격의 구조, 악궁상태, 저작근의 형성 및 기능은 서로 밀접한 연관성을 가지고 있다. 두개악안면 영역의 성장과 발육은 유전적인 요인이외에 환경적인 요인들 즉, 두개안면부의 근육을 포함한 주위조직의 영향을 받는 것으로 이미 알려져 있다. 그러나 반대로 두개안면부의 골격구조가 변화되는 경우 이에 대응하여 두개안면근육의 기능 또한 변화, 적응되는지에 대해서는 체계적인 연구결과가 미흡한 상태이다. 저자는 골격형 제 III급 부정교합자의 악교정수술 전, 후의 근활성도의 변화에 대한 비교연구를 통해 두부 골격구조와 교합상태에 따른 저작근 기능의 상호관계 및 변화 양상에 대해 알아보고자 정상교합을 가진 성인남자 15명과 술전 및 술후 골격형 제 III급 부정교합자 각각 15명을 대상으로 측모두부 방사선사진과 저작효율검사 및 rest, clenching, chewing, swallowing시의 전측두근, 교근, 상순의 근활성도 검사를 시행하여 다음과 같은 결과를 얻었다. 1. 하악의 안정위(rest)에서 술전 부정교합군에서 술후군보다 전측두근, 교근, 상순에서 높은 활성도를 보였으며, 술후군에서는 상순에서만 정상대조군보다 의미있는 높은 근활성도를 보였다. 2. 최대교합(clenching)시는 술후군에서 술전 부정교합군보다 전측두근, 교근, 상순에서 높은 근활성도를 보였다. 3. 저작(chewing)시는 술후군이 술전 부정교합군보다 전측두근 및 교근에서 높은 활성을 보인 반면 상순에서는 감소된 근활성도를 보였다. 4. 연하(swallowing)시 술후군에서 상순은 술전 부정교합군보다 감소되었으나 정상대조군보다 증가된 근활성도를 나타냈으며, 각 군간에 전측두근 및 교근에서는 유의차가 없었다. 5. 저작효율은 술전부정교합군에서 정상대조군보다 낮았으며, 술후군에서 술전 부정교합군보다 증가되었으나 두군 모두 정상대조군과 유의차를 보였다.

• 구강회복응용과학지
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• 제17권4호
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• pp.283-305
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• 2001

The purpose of this study was to analyze the stress distribution of condylar regions and edentulous mandible with implant-supported cantilever prostheses on the certain conditions, such as amount of load, location of load, direction of load, fixation or non-fixation on the condylar regions. Three dimensional finite element analysis was used for this study. FEM model was created by using commercial software, ANSYS(Swanson, Inc., U.S.A.). Fixed model which was fixed on the condylar regions was modeled with 74323 elements and 15387 nodes and spring model which was sprung on the condylar regions was modeled with 75020 elements and 15887 nodes. Six Br${\aa}$nemark implants with 3.75 mm diameter and 13 mm length were incorporated in the models. The placement was 4.4 mm from the midline for the first implant; the other two in each quardrant were 6.5 mm apart. The stress distribution on each model through the designed mandible was evaluated under 500N vertical load, 250N horizontal load linguobuccally, buccal 20 degree 250N oblique load and buccal 45 degree 250N oblique load. The load points were at 0 mm, 10 mm, 20 mm along the cantilever prostheses from the center of the distal fixture. The results were as follows; 1. The stress distribution of condylar regions between two models showed conspicuous differences. Fixed model showed conspicuous stress concentration on the condylar regions than spring model under vertical load only. On the other hand, spring model showed conspicuous stress concentration on the condylar regions than fixed model under 250N horizontal load linguobuccally, buccal 20 degree 250N oblique load and buccal 45 degree 250N oblique load. 2. Fixed model showed stress concentration on the posterior and mesial side of working and balancing condylar necks but spring model showed stress concentration on the posterior and mesial side of working condylar neck and the posterior and lateral side of balancing condylar neck under vertical load. 3. Fixed model showed stress concentration on the posterior and lateral side of working condylar neck and the anterior and mesial side of balancing condylar neck but spring model showed stress concentration on the anterior sides of working and balancing condylar necks under horizontal load linguobuccally. 4. Fixed model showed stress concentration on the posterior side of working condylar neck and the posterior and lateral side of balancing condylar neck but spring model showed stress concentration on the anterior side of working condylar neck and the anterior and lateral side of balancing condylar neck under buccal 20 degree oblique load. 5. Fixed model showed stress concentration on the anterior and lateral side of working condylar neck and the posterior and mesial side of balancing condylar neck but spring model showed stress concentration on the anterior side of working condylar neck and the anterior and lateral side of balancing condylar neck under buccal 45 degree oblique load.. 6. The stress distribution of bone around implants between two models revealed difference slightly. In general, magnitude of Von Mises stress was the greatest at the bone around the most distal implant and the progressive decrease more and more mesially. Under vertical load, the stress values were similar between implant neck and superstructure vertically, besides the greatest on the distal side horizontally. 7. Under horizontal load linguobuccally, buccal 20 degree oblique load and buccal 45 degree oblique load, the stress values were the greatest on the implant neck vertically, and great on the labial and lingual sides horizontally. After all, it was considered that spring model was an indispensable condition for the comprehension of the stress distributions of condylar regions.