• 대한수학회논문집
• /
• 제19권4호
• /
• pp.601-618
• /
• 2004

Throughout this paper, we will consider that R is a near-ring and G an R-group. We initiate the study of monogenic, strongly monogenic R-groups, 3 types of nonzero R-groups and their basic properties. At first, we investigate some properties of D.G. (R, S)-groups, faithful R-groups, monogenic R-groups, simple and R-simple R-groups. Next, we introduce modular right ideals, t-modular right ideals and 3 types of primitive near-rings. The purpose of this paper is to investigate some properties of primitive types near-rings and their characterizations.

• Journal of Korean Neurosurgical Society
• /
• 제59권4호
• /
• pp.400-404
• /
• 2016

We report a case of acute ischemic stroke involving both the anterior and posterior circulation associated with a persistent primitive trigeminal artery (PPTA), treated by endovascular revascularization for acute basilar artery (BA) occlusion via the PPTA. An otherwise healthy 67-year-old man experienced sudden loss of consciousness and quadriplegia. Magnetic resonance imaging showed an extensive acute infarction in the right cerebral hemisphere, and magnetic resonance angiography showed occlusion of the right middle cerebral artery (MCA) and BA. Because the volume of infarction in the territory of the right MCA was extensive, we judged the use of intravenous tissue plasminogen activator to be contraindicated. Cerebral angiography revealed hypoplasia of both vertebral arteries and the presence of a PPTA from the right internal carotid artery. A microcatheter was introduced into the BA via the PPTA and revascularization was successfully performed using a Merci Retriever with adjuvant low-dose intraarterial urokinase. After treatment, his consciousness level and right motor weakness improved. Although persistent carotid-vertebrobasilar anastomoses such as a PPTA are relatively rare vascular anomalies, if the persistent primitive artery is present, it can be an access route for mechanical thrombectomy for acute ischemic stroke.

• Kyungpook Mathematical Journal
• /
• 제54권4호
• /
• pp.595-606
• /
• 2014

In this paper three more right Jacobson-type radicals, $J^r_{g{\nu}}$, are introduced for near-rings which generalize the Jacobson radical of rings, ${\nu}{\in}\{0,1,2\}$. It is proved that $J^r_{g{\nu}}$ is a special radical in the class of all near-rings. Unlike the known right Jacobson semisimple near-rings, a $J^r_{g{\nu}}$-semisimple near-ring R with DCC on right ideals is a direct sum of minimal right ideals which are right R-groups of type-$g_{\nu}$, ${\nu}{\in}\{0,1,2\}$. Moreover, a finite right $g_2$-primitive near-ring R with eRe a non-ring is a near-ring of matrices over a near-field (which is isomorphic to eRe), where e is a right $g_2$-primitive idempotent in R.

• Journal of Korean Neurosurgical Society
• /
• 제49권4호
• /
• pp.226-228
• /
• 2011

We report a case of spontaneous right carotid-cavernous fistula (CCF) in a proximal segment of persistent primitive trigeminal artery (PPTA) and combined vascular anomalies such as left duplicated hypoplastic proximal posterior cerebral arteries and a variation of anterior choroidal artery supplying temporal and occipital lobe. A 45-year-old male presented with progressive right exophthalmos, diplopia, and ocular pain. With manual compression of the internal carotid artery, a cerebral angiography revealed a right CCF from a PPTA. Treatment involved the placement of detachable non-fibered and fibered coils, and use of a hyperglide balloon to protect against coil herniation into the internal carotid artery. A final angiograph revealed complete occlusion of PPTA resulted in no contrast filling of CCF.

• 대한수학회지
• /
• 제51권3호
• /
• pp.463-472
• /
• 2014

Let R be a ring with identity 1, I(R) be the set of all nonunit idempotents in R and $S_{\ell}$(R) (resp. $S_r$(R)) be the set of all left (resp. right) semicentral idempotents in R. In this paper, the following are investigated: (1) $e{\in}S_{\ell}(R)$ (resp. $e{\in}S_r(R)$) if and only if re=ere (resp. er=ere) for all nilpotent elements $r{\in}R$ if and only if $fe{\in}I(R)$ (resp. $ef{\in}I(R)$) for all $f{\in}I(R)$ if and only if fe=efe (resp. ef=efe) for all $f{\in}I(R)$ if and only if fe=efe (resp. ef=efe) for all $f{\in}I(R)$ which are isomorphic to e if and only if $(fe)^n=(efe)^n$ (resp. $(ef)^n=(efe)^n$) for all $f{\in}I(R)$ which are isomorphic to e where n is some positive integer; (2) For a ring R having a complete set of centrally primitive idempotents, every nonzero left (resp. right) semicentral idempotent is a finite sum of orthogonal left (resp. right) semicentral primitive idempotents, and eRe has also a complete set of primitive idempotents for any $0{\neq}e{\in}S_{\ell}(R)$ (resp. 0$0{\neq}e{\in}S_r(R)$).

• Annals of Clinical Neurophysiology
• /
• 제23권2호
• /
• pp.126-129
• /
• 2021

We present a patient with a primitive neuroectodermal tumor arising from the right atrium who experienced multiple syncope episodes daily, which had first appeared 1 month after surgery. The symptoms continued to worsen over the course of chemotherapy, and the autonomic function test (AFT) was performed after the 14th chemotherapy cycle. The AFT revealed orthostatic hypotension and reduced baroreflex-dependent sympathetic reactivity. Physical counterpressure techniques were applied with a visual biofeedback intervention, and were found to be effective in reducing the syncope episodes.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(II)
• /
• pp.1100-1103
• /
• 1987

In this paper, we report a method for the primitive segments extraction from printed Korean characters without thinning as a preliminary stage to design an efficient recognition system. The primitive segments are defined by fundamental subpatterns which are vertical(I), right sloping(/), left. sloping(\). horizontal(-), and circular segment(o). The circular segment among the five kinds of segment is different from the others in geometrical properties. Therefore, at first, the circular segment is extracted by using the closed circle of the inner boundary and the geometrical characteristics of its outer. Next, linear segments are separated from the character pattern by means of a directional coding method. Finally, primitive segments are extracted from each set of linear segments by using a projection profile which involves the fact whether the segment has branches or not. The experimental results show that this method reduces computation time and storage space in comparision with the existing methods.

• Journal of Chest Surgery
• /
• 제25권3호
• /
• pp.315-320
• /
• 1992

Pulmonary arteriovenous fistula is a rare congenital vascular malformation resulting from abnormal capillary development with incomplete formation of vascular septum normally dividing the primitive connections between the venous and arterial plexuses. Recently we have experienced a case of the bilateral pulmonary arteriovenous fistula in 7 years-old female patient. On admission, clinical manifestations were cyanosis of lips, clubbing and cyanosis of digits, and exertional dyspnea. The PO2 in arterial blood gas analysis was 43.3mmHg. In left upper and right lower lobe pulmonary arteriovenous fistulas were confirmed by bilateral pulmonary angiography. Left upper lobectomy and wedge resection of right lower lobe were performed respectively. Postoperative results were good.

• 대한지리학회지
• /
• 제45권3호
• /
• pp.414-429
• /
• 2010

이어도 영유권 분쟁에 있어서 인접국인 중국의 부당한 주장에 대해 한국으로서 정합적인 논리를 개발 설득함으로써 문제를 평화적으로 해결하는 데 본 연구의 목적이 있다. 이를 위해 먼저 이어도의 자연경관의 특징과 형성과정을 자연지리학으로 정리하고. 이를 토대로 중국의 견강부회적인 주장에 대해 구체적이고 객관적인 반박 논리를 개발한다. 지질 지형과 관련한 지질사를 봤을 때 이어도가 제주도의 부속암초라는 사실이 그대로 드러나고 있으며, 중국이 주장하는 인문학적 증거, 즉 $\ll$산해경$\gg$에 대한 중국측의 해석은 우려할 정도로 왜곡되고 있다. 뿐만 아니라 중국측이 주장하는 논리가 북해대륙붕사건에서 독일의 논리를 도입하고 있으나 중국은 대향국간과 인접국간의 경계획정을 혼동하고 있어 정합성이 전혀 없다고 해도 과언이 아니다. 본 연구 결과는 강단지리학에 관심을 갖도록 할 뿐만 아니라 나아가 국민을 계도하고 관계기관이 상대국과 협상할 때 주요자료와 이론으로 활용할 수 있다.

• Journal of Korean Neurosurgical Society
• /
• 제49권6호
• /
• pp.359-362
• /
• 2011

Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET) is an unusual malignancy with aggressive behavior. ES/PNET in the cerebellopontine angle (CPA) is extremely uncommon, and we report on a rare case here. A 31-year-old man presented with one month history of left facial palsy, hearing loss, swallowing difficulty, and hoarseness. Magnetic resonance images showed a large mass in the left CPA and a small one in the right cerebellar hemisphere. The patient underwent a surgery for the CPA mass lesion, and the pathology was compatible with ES/PNET. Radiation therapy and chemotherapy were administered. In contrast to the initial radiologic findings resembling vestibular schwannoma or meningioma, ES/PNET had several distinct clinical features. A patient with a CPA mass and presenting unusual clinical features should be suspected of having a rare malignancy.