• Communications of the Korean Mathematical Society
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• v.19 no.4
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• pp.601-618
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• 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
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• v.59 no.4
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• pp.400-404
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• 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
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• v.54 no.4
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• pp.595-606
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• 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
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• v.49 no.4
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• pp.226-228
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• 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.

• Journal of the Korean Mathematical Society
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• v.51 no.3
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• pp.463-472
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• 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
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• v.23 no.2
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• pp.126-129
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• 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.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1100-1103
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• 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
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• v.25 no.3
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• pp.315-320
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• 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.

• Journal of the Korean Geographical Society
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• v.45 no.3
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• pp.414-429
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• 2010

With regard to Ieodo, South Korea and China argue that Ieodo belongs to their territory respectively, considering its history. However, both parties haven't suggested concrete evidence to support their argument. Even if they suggest corroborative facts, they are distorted or exaggerated like myth. Therefore, it is important by what side primitive title and effective control are exercised in settling the problem of Ieodo. The issue was to suggest coherence logic by finding concrete geographical facts in the East China Seat the time of applying a method of boundary decision followed by the marine act, namely principle of median line and principle of equidistance. China has argued that China should occupy most of continental shelf in the East China Sea on the basis of silt, a deposit of the continent. However, the base of the East China Sea is a part of Eurasian Plate. In addition, a geographical contribution to formation of the continent shelf by the Korean Peninsula is equal to the Chinese Continent. Ieodo is 'Island of mythos' in China, but is 'Island of legend' suggested by concrete facts in South Korea. Therefore, its cultural titile and primitive title are belonged to South Korea, before its historical title.

• Journal of Korean Neurosurgical Society
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• v.49 no.6
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• pp.359-362
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• 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.