• Journal of the Society of Naval Architects of Korea
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• v.55 no.1
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• pp.66-74
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• 2018

In order to evaluate the precision degree of the blocks on the dock, the shipyards recently started to use the point cloud approaches using the 3D scanners. However, they hesitate to use it due to the limited time, cost, and elaborative effects for the post-works. Although it is somewhat traditional instead, they have still used the electro-optical wave devices which have a characteristic of having less dense point set (usually 1 point per meter) around the contact section of two blocks. This paper tried to expand the usage of point sets. Our approach can estimate the rework time to weld between the Pre-Erected(PE) Block and Erected(ER) block as well as the precision of block construction. In detail, two algorithms were applied to increase the efficiency of estimation process. The first one is K-mean clustering algorithm which is used to separate only the related contact point set from others not related with welding sections. The second one is the Concave hull algorithm which also separates the inner point of the contact section used for the delayed outfitting and stiffeners section, and constructs the concave outline of contact section as the primary objects to estimate the rework time of welding. The main purpose of this paper is that the rework cost for welding is able to be obtained easily and precisely with the defective point set. The point set on the blocks' outline are challenging to get the approximated mathematical curves, owing to the lots of orthogonal parts and lack of number of point. To solve this problems we compared the Radial based function-Multi-Layer(RBF-ML) and Akima interpolation method. Collecting the proposed methods, the paper suggested the noble point matching method for minimizing the rework time of block-welding on the dock, differently the previous approach which had paid the attention of only the degree of accuracy.

• 한국지구물리탐사학회:학술대회논문집
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• 2006.06a
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• pp.201-206
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• 2006

Earth sciences is undergoing a gradual but massive shift from description of the earth and earth systems, toward process modeling, simulation, and process visualization. This shift is very challenging because the underlying physical and chemical processes are often nonlinear and coupled. In addition, we are especially challenged when the processes take place in strongly heterogeneous systems. An example is two-phase fluid flow in rocks, which is a nonlinear, coupled and time-dependent problem and occurs in complex porous media. To understand and simulate these complex processes, the knowledge of underlying pore-scale processes is essential. This paper presents a new attempt to use pore-scale simulations for understanding physical properties of rocks. A rigorous pore-scale simulator requires three important traits: reliability, efficiency, and ability to handle complex microstructures. We use the Lattice-Boltzmann (LB) method for singleand two-phase flow properties, finite-element methods (FEM) for elastic and electrical properties of rocks. These rigorous pore-scale simulators can significantly complement the physical laboratory, with several distinct advantages: (1) rigorous prediction of the physical properties, (2) interrelations among the different rock properties in a given pore geometry, and (3) simulation of dynamic problems, which describe coupled, nonlinear, transient and complex behavior of Earth systems.

• Cartoon and Animation Studies
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• s.48
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• pp.1-22
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• 2017

Independent short animation was the expression method for young animation creators through creative and progressive representation. Since the birth of animation, independent short animation has become a driving force for qualitative development and diversification of animation. This has brought many works to the world that emphasize experimentation and challenges in the history of animation and in countries that have the rich animation resources such as France, Japan, and Canada, they recognize its importance and supports young creators in order to maintain the value of it. However, Korean animations are evaluated the quality of works by the popularity of the children, moreover, companies that focus on developing and selling products, including toys, rather than animation works themselves and public awareness that accepts them are formed throughout the Korean animation industry. Because of these points, Korean animation creators can not express the creative vision for the future and philosophical awareness of the problem and they are trapped in commercial animation markets. In order to re-leap and expand the Korean animation industry, which has reached the saturation level with infant animation, it is necessary to reestablish the value of independent short animations with challenging and experimental characteristics and requires the creative environment and support system for the diversity of Korean animation industries, including the achieving commercial goals through good planning, story development and technological innovation. For this purpose, this paper analyzes the current state of production, screening, distribution, and government support of independent short animation in Korea, and explores the structural problems and solutions.

• Journal of Trauma and Injury
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• v.26 no.3
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• pp.170-174
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• 2013

Purpose: A flail chest is one of most challenging problems for trauma surgeons. It is usually accompanied by significant underlying pulmonary parenchymal injuries and mayled to a life-threatening thoracic injury. In this study, we evaluated the treatment result for a flail chest to determine the effect of trauma localization on morbidity and mortality. Methods: Between 2004 and 2011, 46 patients(29 males/17 females) were treated for a flail chest. The patients were divided into two group based on the location of the trauma in the chest wall; Group I contained patients with an anterior flail chest due to a bilateral costochondral separation (n=27) and Group II contained patients with a single-side posterolateral flail chest due to a segmental rib fracture (n=19). The location of the trauma in the chest wall, other injuries, mechanical ventilation support, prognosis and ISS (injury severity score) were retrospectively examined in the two groups. Results: Mechanical ventilation support was given in 38 patients(82.6%), and 7 of these 38 patients required a subsequent tracheostomy. The mean ISS for all 46 patients was $19.08{\pm}10.57$. Between the two groups, there was a significant difference in mean ventilator time (p<0.048), but no significant difference in either trauma-related morbidity (p=0.369) or mortality (p=0.189). Conclusion: An anterior flail chest frequently affects the two underlying lung parenchyma and can cause a bilateral lung contusion, a hemopneumothorax and lung hemorrhage. Thus, it needs longer ventilator care than a lateral flail chest does and is more frequently associated with pulmonary complications with poor outcome than a lateral flail chest is. In a severe trauma patient with a flail chest, especially an anterior flail chest, we must pay more attention to the pulmonary care strategy and the bronchial toilet.

• Proceedings of the KACD Conference
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• 2001.05a
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• pp.247-251
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• 2001

;A dental developmental anomaly is defined as an isolated aberration in tooth form, caused by a disturbance or abnormality which occurred during tooth development. There are numerous types of dental anomalies, and a considerable variation in the extent of the defects occurs with each type. Teeth with these anomalies pose unique challenges. Since the defects are not always apparent clinically, they can confuse diagnosticians investigating the etiology of pulpal pathosis. When endodontic treatment is required, the defects often hinder access cavity preparation and canal instrumentation. Treatment planning also becomes more challenging, since the defects can create complicated periodontal problems, and the malformed teeth can be difficult to restore, particularly those weakened by endodontic therapy. Fusion is defined as the joining of two developing tooth germs resulting in a single large tooth structure. The incidence of fusion is < 1% in the Caucasian population, and it is believed that physical force or pressure produces contact of the developing teeth. Clinically and radiographically, a fused tooth usually appears as one large crown with at least partially separated roots and root canals. There may be a vertical groove in the tooth crown delineating the originally separate crowns. Dens invaginatus is a deep surface invagination of the crown or root that is lined by enamel. Teeth in both maxillary and mandibular arches may be affected, but the permanent maxillary lateral incisor is the tooth most commonly involved. Studies have revealed an incidence ranging from 0.25% to as high as 10%. The invagination ranges from a slight pitting to an anomaly occupying most of the crown and root. The invagination frequently communicates with the oral cavity, allowing the entry of irritants and microorganism either directly into pulpal tissues or into an area that is deparated from pulpal tissues by only a thin layer of enamel and dentin. This continuous ingress of irritants and the subsequent inflammation usually lead to necrosis of the adjacent pulp tissue and then to periapical or periodontal abscesses. If the invagination extends from the crown to the periradicular tissue and has no communication with the root canal system, the pulp may remain vital. Recommended treatment of fused tooth and dens invaginatus has been reported in the endodontic literature. This case report describes the endodontic treatment of a maxillary laterl incisors having fused crown and dens invaginatus.natus.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.593-596
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• 2018

The speed of vehicles has remained a significant factor that influences the severity of accidents and traffic accident rate in many parts of the world including South Korea. This behavior where drivers drive at speeds which exceed a posted safe threshold is known as 'speeding'. Over the past twenty years, the Korean National Police Agency (NPA) has become aware of an increased frequency of drivers who are speeding. Therefore, fixed-type ASE systems [1] have been installed on hazardous road sections of many highways. These system monitor vehicle speeds using a camera. However, the use of ASE systems has changed the behavior of the drivers. Specifically, drivers reduce speed or avoid the route where the cameras are mounted. It is not practical to install cameras at every possible location. Therefore, it is challenging to thoroughly explore the location where speeding occurs. In view of these problems, the author of this paper designed and implemented a prototype visualization system in which point and color are used to show vehicle location and associated over-speed information. All of this information was used to create a comprehensive visualization application to show information about vehicle driving. In this paper, we present an approach detecting vehicles moving at speeds which exceed a threshold and visualizing the points those violations occur on a map. This was done using vehicle trajectory data collected in Daegu city. We propose steps for exploring the data collected from those sensors. The resulting mapping has two layers. The first layer contains the dynamic vehicle trajectory data. The second underlying layer contains the static road networks. This allows comparing the speed of vehicles on roads with the known maximum safe speed of those roads, and presents the results with a visualization tool. We also compared data about people who drive over threshold safe speeds on each road on days and weekends based on vehicle trajectories. Finally, our study suggests improved times and locations where law enforcement should use monitoring with speed cameras, and where they should be stricter with traffic law enforcement. We learned that people will drive over the speed limit at midnight more than 1.9 times as often when compared with rush hour traffic at 8 o'clock in the morning, and 4.5 times as often when compared with traffic at 7 o'clock in the evening. Our study can benefit the government by helping them select better locations for installation of speed cameras. This would ultimately reduce police labor in traffic speed enforcement, and also has the potential to improve traffic safety in Daegu city.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.12 no.4
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• pp.191-200
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• 2017

As Korea experienced a Asian foreign exchange crisis in 1997 and a world financial crisis in 2008, the social structure of Korea has undergone many changes. The problem of polarization has become more serious, and the social class has become harder to move between strata. This problem has been accompanied by a growing sense of crisis that the power of social development can be lost along with the problem of population cliffs. Behind the crisis is a reflection of the fact that the growth-oriented economic policies and welfare policies implemented in various European countries can not solve the problem. As an alternative to this, the emergence of social enterprises is attracting attention. Social enterprises have the characteristic of seeking to generate economic profit in order to achieve the purpose of the public interest to provide jobs to the underprivileged. In recent years, the importance of social ventures to expand the scope of new social enterprises in innovative ways has increased. The social venture is a venture business in that it takes risks to develop new areas, not existing business areas, but it also has the character of a social enterprise to achieve the public interest. In other words, an innovative corporate model that provides a creative and challenging solution of social problems in the venture spirit. Although the interest and importance of social enterprises and social ventures are increasing, this academic research is still lacking. The purpose of this study is to introduce and analyze cases of successful social enterprises and social ventures in order to reflect these social interests and their importance and to fill the gap of previous studies. In addition, I hope that this study will stimulate interest and research on the start - up of social venture.

• Archives of Plastic Surgery
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• v.36 no.5
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• pp.583-590
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• 2009

Purpose: In the cases of a vascular compromised condition in an injured lower extremity, soft tissue coverage with free tissue transfer presents a challenging problem to the reconstructive surgeon. For this reason, cross - leg flaps are still used in unusual circumstances. Advances in surgical technique has made the cross - leg free flap possible although it may require long operation time along with significant donor site morbidity. Therefore, a pedicled cross - leg muscle flap may be an alternative treatment modality when local flap or free flap is not possible. Methods: Twelve patients(9 males and 3 females) underwent the operation between October of 2001 and December of 2008. The patients' age ranged from 6 to 82 years. The unusual defects included the regions such as the knee, popliteal fossa, distal third of the tibia, dorsal foot, and the heel. Indications for the cross - leg gastrocnemius flap are inadequate recipient vessels for free flap(in eight cases), extensive soft tissue injuries(in three cases) and free flap failure(in one case). The muscle flap was elevated from contralateral leg and transferred to the soft tissue defect on the lower leg while both legs were immobilized with two connected external fixator systems. Delay procedure was performed 2 weeks postoperatively, and detachment was done after the establishment of the adequate circulation. The average period from the initial flap surgery to detachment was 32 days (3 to 6 weeks). Mean follow - up period was 4 years. Results: Stable coverage was achieved in all twelve patients without any flap complications. Donor site had minimal scarring without any functional and cosmetic problems. No severe complications such as deep vein thrombosis or flap necrosis were noted although mild to moderate contracture of the knee and ankle joint developed due to external fixation requiring 3 to 4 weeks of physical treatment. All patients were able to walk without crutches 3 months postoperatively. Conclusion: Although pedicled cross - leg flaps may not substitute free flap surgery, it may be an alternative method of treatment when free flap is not feasible. Using this modification of the gastrocnemius flap we managed to close successfully soft tissue defects in twelve patients without using free tissue transfers.

• Journal of Broadcast Engineering
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• v.24 no.4
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• pp.592-601
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• 2019

For coronary procedures, X-ray angiogram images are useful for diagnosing and assisting procedures. It is challenging to accurately segment a coronary artery using only a single segmentation model in 2D X-ray images due to a complex structure of three-dimensional coronary artery, especially from phenomenon of vessels being broken in the middle or end of coronary artery. In order to solve these problems, the initial segmentation is performed using an existing single model, and the candidate regions for the sophisticate correction is estimated based on the initial segment, and the local patch-based correction is performed in the candidate regions. Through this research, not only the broken coronary arteries are re-connected, but also the distal part of coronary artery that is very thin is additionally correctly found. Further, the performance can be much improved by combining the proposed correction method with any existing coronary artery segmentation method. In this paper, the U-net, a fully convolutional network was chosen as a segmentation method and the proposed correction method was combined with U-net to demonstrate a significant improvement in performance through X-ray images from several patients.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.4
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• pp.202-217
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• 2018

Urban land use changes by human activities affect spatial configuration of urban areas and their surrounding ecosystems. Although it is necessary to identify patterns of urban land use changes and to simulate future changes for sustainable urban management, simulation of land use changes is still challenging due to their uncertainty and complexity. Cellular automata model is widely used to simulate urban land use changes based on cell-based approaches. However, cell-based models can not reflect features of actual land use changes and tend to simulate fragmented patterns. To solve these problems, object-based cellular automata models are developed, which simulate land use changes by land patches. This study simulate future land use changes in Hanam city using an object-based cellular automata model. Figure of merit of the model is 24.1%, which assess accuracy of the simulation results. When a baseline scenario was applied, urban decreased by 16.4% while agriculture land increased by 9.0% and grass increased by 19.3% in a simulation result of 2038 years. In an urban development scenario, urban increased by 22.4% and agriculture land decreased by 26.1% while forest and grass did not have significant changes. In a natural conservation scenario, urban decreased by 29.5% and agriculture land decreased by 8.8% while each forest and grass increased by 6% and 42.8%. The model can be useful to simulate realistic urban land use change effectively, and then, applied as a decision support tool for spatial planning.