• 대한수학회지
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• 제54권4호
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• pp.1281-1299
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• 2017

A submodule N of a module M is called ${\mathcal{S}}$-closed (in M) if M/N is nonsingular. It is well-known that the class Closed of short exact sequences determined by closed submodules is a proper class in the sense of Buchsbaum. However, the class $\mathcal{S}-Closed$ of short exact sequences determined by $\mathcal{S}$-closed submodules need not be a proper class. In the first part of the paper, we describe the smallest proper class ${\langle}\mathcal{S-Closed}{\rangle}$ containing $\mathcal{S-Closed}$ in terms of $\mathcal{S}$-closed submodules. We show that this class coincides with the proper classes projectively generated by Goldie torsion modules and coprojectively generated by nonsingular modules. Moreover, for a right nonsingular ring R, it coincides with the proper class generated by neat submodules if and only if R is a right SI-ring. In abelian groups, the elements of this class are exactly torsionsplitting. In the second part, coprojective modules of this class which we call ec-flat modules are also investigated. We prove that injective modules are ec-flat if and only if each injective hull of a Goldie torsion module is projective if and only if every Goldie torsion module embeds in a projective module. For a left Noetherian right nonsingular ring R of which the identity element is a sum of orthogonal primitive idempotents, we prove that the class ${\langle}\mathcal{S-Closed}{\rangle}$ coincides with the class of pure-exact sequences of modules if and only if R is a two-sided hereditary, two-sided $\mathcal{CS}$-ring and every singular right module is a direct sum of finitely presented modules.

• 정보관리학회지
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• 제31권4호
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• pp.179-200
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• 2014

본 연구는 대학도서관과 공공도서관에서 영상물 이용현황과 그에 따른 저작권 문제를 조사하였다. 이를 위하여 공공도서관과 대학도서관을 대상으로 설문조사를 실시하였으며, 사서의 저작권 문제는 설문조사와 더불어 도메리와 저작권 관련 웹사이트 등의 질문을 분석하였다. 그 결과 영상자료를 위한 설비의 다양화와 서비스의 다양화에 따라 저작권 문제도 공연뿐만 아니라 대출, 보존용 복제, 디지털화, 인터넷을 통한 서비스 등 다양하게 발생하고 있음을 알 수 있었다. 또한 각 영역별 저작권 질문이 기초적인 질문에서부터 세부적인 문제에 대한 질문까지 다양하게 이루어지고 있었다. 이와 관련하여 본 연구는 저작권 문제의 복잡성을 고려해 볼 때 사서양성과 관련한 대학 정규교육과정에서 저작권에 대한 기초적 이해를 위한 교육, 직무연수과정에서 저작권법의 개정에 따른 보완 교육, 세부적인 저작권 문제에 대한 해결을 위해서 사서를 위한 온라인 질의응답 서비스가 실시될 필요가 있음을 제안하였다.

• 의료법학
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• 제10권1호
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• pp.11-38
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• 2009

"Bioethics" may have various meanings depending on its roles. It may mean professional ethics for scientists and physicians, etc. It may also mean an academic discipline using interdisciplinary approach as well as a philosophical or a legal approach. "Bioethics" as an interdisciplinary study should often deal with public policy on bioethical issues. I call this role bioethics as a study of bioethics policy, which has to be developed as a new discipline. From this perspective, I deal with bioethical issues relevant to a human life before birth. There are various and often conflicting arguments about the moral status of a human life before birth such as the fertilization argument, the argument of genetic identity, so-called the "14 days" argument focusing on the formation of primitive streak, the argument of sentient being, and Michael Sandle's argument of an embryo as a being between a thing and a person. I argue that each of them is reasonable. Thus we are faced with reasonable disagreement on the views over whether a human life before birth has the same right to life as that of a person or whether right to life may be considered to be a matter of degree. If we acknowledge reasonable disagreement, as John Rawls pointed out, we should tolerate the views from ours in a plural society. Therefore, we cannot help making a policy that allows abortion and embryonic research with some limitations. When we say a certain act is morally permissible, "moral permissibility" does not mean that the act is morally right for all. Rather it means that the act cannot help being morally allowed for some persons although the others do not believe its moral rightness because they cannot right now rationally persuade others to accept their view.

• Journal of Korean Neurosurgical Society
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• 제44권5호
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• pp.338-340
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• 2008

A rare case of ruptured aneurysm associated with multiple $A_1$ fenestrations resembling plexiform network was demonstrated by 3D angiography. A 56-year-old female presented with a ruptured aneurysm in the $A_2$ segment of the left distal anterior cerebral artery associated with the right $A_1$ fenestration. The ruptured aneurysm was occluded with surgical neck clipping via interhemispheric approach without neurological deficit. Plexiform fenestrations of the right distal $A_1$. opposite side to the left ruptured $A_2$ aneurysm, were clearly visible on postoperative 3D angiography. Our case may strongly support the theory described by Paget, namely that a remnant of the plexiform anastomosis between the primitive olfactory artery and $A_1$ segment is the source of such fenestration.

• Journal of Chest Surgery
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• 제16권3호
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• pp.362-367
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• 1983

Pulmonary arteriovenous fistula is a congenital malformation resulting from errant capillary development, with incomplete formation or disintegration of the vascular septa that normally divide the primitive connections between the venous and arterial plexuses. It generally occurs as part of the disorder known as hereditary hemorrhagic telangiectasia [Rendu-Osler-Weber disease]. The hereditary lesion is transmitted as a simple non-sex-linked dominant trait. It may be single or multiple, too small to see on plain chest films or large and easily recognized. One third of the lesions are multiple on plain chest film. The pathogenesis of its symptoms is that unoxygenated, desaturated arterial blood enters into the pulmonary venous system, directly. Recently we have experienced a case of the pulmonary arteriovenous fistula in 26 years old male soldier, which was confirmed by pulmonary angiography preoperatively. 2 thumb-tip sized, well circumscribed cystic masses filled with bright red colored blood were seen in subpleural and anterolateral portion of the right upper lobe. Right upper Iobectomy was performed due to close approximation of the fistula with pulmonary vein. Microscopically, it shows angiomatous dilatation of the abnormal vessels embedding in the parenchyma. Postoperative physiologic studies show nearly normal arterial oxygen saturation, hemoglobin and RBC count. There was good, uneventful postoperative course.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권7호
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• pp.2703-2718
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• 2015

Nowadays, public cloud storage is gaining popularity and a growing number of users are beginning to use the public cloud storage for online data storing and sharing. However, how the encrypted data stored in public clouds can be effectively shared becomes a new challenge. Proxy re-encryption is a public-key primitive that can delegate the decryption right from one user to another. In a proxy re-encryption system, a semi-trusted proxy authorized by a data owner is allowed to transform an encrypted data under the data owner's public key into a re-encrypted data under an authorized recipient's public key without seeing the underlying plaintext. Hence, the paradigm of proxy re-encryption provides a promising solution to effectively share encrypted data. In this paper, we propose a new certificate-based proxy re-encryption scheme for encrypted data sharing in public clouds. In the random oracle model, we formally prove that the proposed scheme achieves chosen-ciphertext security. The simulation results show that it is more efficient than the previous certificate-based proxy re-encryption schemes.

• Journal of Korean Neurosurgical Society
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• 제38권4호
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• pp.312-315
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• 2005

The persistent hypoglossal artery[PHA] is a rare anomaly that belongs to the group of embryonic carotid-basilar artery anastomoses that may occur in adults. The most commonly reported type of such an anastomosis is the primitive trigeminal artery, followed by the PHA. We report a 35-year old man, hospitalized because of an intraventricular hemorrhage, who was found to have a right persistent PHA. Three-dimensional computed tomography[CT] angiography provided excellent anatomical topology of the anomaly. To our knowledge, this patient is the first case of a PHA identified by this means in Korea.

• Advances in pediatric surgery
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• 제12권1호
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• pp.17-23
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• 2006

A 3-year-old girl with a primitive neuroectodermal tumor (PNET) and a 6-yearold girl with acute lymphoid leukemia were referred to us because of problems with their implantable central venous ports (Port-A-Cath$^{(R)}$). On physical examination, the ports were upside-down, so a needle could notbe inserted through the membrane of the port. Right lateral side view of the chest radiogram confirmed port inversion in both cases. At operation, the ports were inverted and the transfixing sutures were totally absorbed. The ports were rotated 180 degrees and anchoring sutures placed.

• International Journal of Contents
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• 제8권3호
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• pp.79-82
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• 2012

In digital contents distribution environments, a user authentication is an important security primitive to allow only authenticated user to use right services by checking the validity of membership. For example, in Internet Protocol Television (IPTV) environments, it is required to provide an access control according to the policy of content provider. Remote user authentication and key agreement scheme is used to validate the contents accessibility of a user. We propose a novel user authentication scheme using smart cards providing a secure access to multimedia contents service. Each user is authenticated using a subset of attributes which are issued in the registration phase without revealing individual's identity. Our scheme provides the anonymous authentication and the various permissions according to the combination of attributes which are assigned to each user. In spite of more functionality, the result of performance analysis shows that the computation and communication cost is very low. Using this scheme, the security of contents distribution environments in the client-server model can be significantly improved.

• 대한수의학회지
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• 제61권3호
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• pp.27.1-27.4
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• 2021

A 13-year-old castrated Maltese dog was presented to a local animal hospital with an oral hemorrhage. An intraoral examination revealed an irregular proliferated lobular mass at the right side of the maxillary gingiva and hard palate. A surgically excised mass was requested for a histopathology examination. Histopathologically, the neoplastic foci were composed of biphasic morphologic patterns, such as primitive mesenchymal tissue and mature or immature cartilage tissue. Immunohistochemically, most of the neoplastic cells forming cartilaginous islands tested positive for S-100; the surrounding mesenchymal cells tested positive for vimentin. This paper describes a rare case of mesenchymal chondrosarcoma in the maxillary gingiva of a Maltese dog.