원형편파특성과 반송파 간섭신호특성을 적용한 OFDM 시스템 성능 개선

안재성,하덕호,Ahn, Je-Sung,Ha, Deock-Ho 한국통신학회 2007 韓國通信學會論文誌 Vol.32 No.8a

OFDM(Orthogonal Frequency Division Multiplexing)신호는 독립적으로 변조된 다수의 부반송파들이 동위상으로 더해질 경우 신호의 크기가 크게 발생하여 PAPR(Peak-to-Average Power Ratio)이 크게 나타난다. PAPR이 커지면 시스템의 복잡도가 증가하고 RF 전력증폭기의 효율이 감소하므로 시스템의 성능 열화의 요인이 된다. 본 논문에서는, 기존의 OFDM 시스템의 BER 성능과 PAPR 특성을 개선하기위하여 페이딩 특성에 강인한 효과를 나타내는 원형편파와 반송파 간섭신호를 시스템에 함께 적용하여 컴퓨터 모의실험으로 그 성능을 평가하였다. 그 결과 시스템 BER 특성이 $2{\sim}3$[dB] 정도의 개선효과가 있었으며 PAPR특성도 크게 감소시킬 수 있음을 알 수가 있었다. In this paper, in order to enhance the performance improvements of both BER and PAPR characteristic for the conventional OFDM system, both circularly polarized waves and carrier interferometry signals which shows the robustic fading reduction effect are applied to the system, and then the performance of the proposed system has been evaluated by computer simulation. From the analysis, it can be seen that the system BER performance can be improved by 2 or 3 dB. Furthermore, it can be also seen that the PAPR characteristic can be markedly reduced.

기저동맥 분지부 동맥류의 치료결과

안재성,김정훈,권양,권병덕,Ahn, Jae Sung,Kim, Jung Hoon,Kwon, Yang,Kwun, Byung Duk 대한신경외과학회 2000 Journal of Korean neurosurgical society Vol.29 No.7

Objective : The authors analyzed the results of management outcomes for basilar bifurcation aneurysms treated with transcranial surgery and endovascular surgery. Methods : At the authors' institution between May 1989 and December 1998, 47 aneurysms with 45 patients were treated with transcranial surgery including surgical clipping/wrapping and endovascular surgery for basilar bifurcation aneurysms. The medical records and neuroimaging studies of the patients were reviewed retrospectively. Results : Of the 45 patients, 87 percent of the aneurysms were ruptured and 13% unruptured. Forty six percent of the patients had multiple aneurysms including basilar bifurcation aneurysm. Of the 39 patients with subarachnoid hemorrahge, 77% were in good neurological status(Hunt Hess grade I-III), 23% were in poor grade(H-H grade IV-V). Thirty two patients were treated with transcranial surgery and 15 patients were treated with endovascular surgery. Two patients who had treated with wrapping surgery later bled during follow-up period and treated with endovascular surgery. The management outcome of the transcranial surgery was : Glasgow outcome scale(GOS) I 66%, GOS II 12.5%, GOS III 6.3%, GOS IV 6.3% and GOS V(death) 9.4%. The major causes of morbidity related to transcranial surgery were perforator occlusion, vasospasm and retraction injury. The management outcome of the endovascular surgery was : GOS I 66.7%, GOS II 6.7%, and GOS V 26.7%. The major causes of mortality related to endovascular surgery were related to intraoperative aneurysmal bleeding. Conclusion : This report documents that more than 75% of patients undergoing treatment either transcranial or endovascular surgery can expect good clinical outcomes. Treatment modality in management of basilar bifurcation aneurysm must be carefully selected based on various considering factors.

추골동맥 및 분지부 동맥류의 치료결과

안재성,김준수,김정훈,권양,권병덕,Ahn, Jae Sung,Kim, Joon Soo,Kim, Jeong Hoon,Kwon, Yang,Kwun, Byung Duk 대한신경외과학회 2001 Journal of Korean neurosurgical society Vol.30 No.1

Objective : Aneurysms of vertebral artery and its branches make up approximately 3% of all intracranial aneurysms. As the aneurysm have an intimate relationship with lower cranial nerves and medulla, surgical management of the aneurysms are one of the challenging neurosurgical problems. The authors analyzed the management outcomes for aneurysms arising from vertebral artery and its branches. Methods : At the authors' institution between May 1989 and Jan. 2000, 42 patients were treated with transcranial and endovascular surgery for aneurysms of vertebral artery and its branches. The medical records and neuroimaging studies of the patients were reviewed retrospectively. Results : Forty two patients were comprised of 28 female and 14 male patients aged from 26-80 year old(mean : 51.8). Of the 42 patients, 37 patients(88%) had subarachnoid hemorrhage. Of the 37 patients with subarachnoid hemorrahge, 35 patients(95%) were in good neurological status(Hunt Hess grade I-III), 2 patients(5%) in poor grade(H-H grade IV-V) before operation. Location of the aneurysm were 16 in vertebral artery, 12 in vertebro-PICA junction, and 14 in the peripheral PICA. Twenty nine patients were treated with transcranial surgery and 13 patients with endovascular surgery. The management outcome of the transcranial surgery was : Glasgow outcome scale(GOS) I and II ; 24, GOS III ; 2, GOS IV ; 1 and GOS V(death) ; 2. The causes of mortality related to transcranial surgery were rebleeding after failure in clipping in one and suspected brainstem infarct in one. Morbidity was attributed to vasospasm(3), lower CN palsy(7, including temporary dysfunction) and pseudomeningocele(1). The management outcome of the endovascular surgery was : Glasgow outcome scale(GOS) I-II ; 9, GOS III ; 1, GOS IV ; 1, and GOS V(death) ; 2. The causes of mortality related to endovascular surgery were sepsis from pneumonia(1) and vasospasm(1). There were one cerebellar infarct and one lateral medullary syndrome. Conclusion : Excellent and good surgical results can be expected in 80% of the patients with aneurysms of vertebral arery and its branches. The outcomes of endovascular surgery in treating vertebral artery aneurysm were satisfactory and endovascular surgery may offer a therapeutic alternative especially in vertebral dissecting aneurysm.

비파열 뇌동맥류의 치료-자연경과 및 수술적 치료결과

안재성,권병덕,Ahn, Jae Sung,Kwun, Byung Duk 대한신경외과학회 2001 Journal of Korean neurosurgical society Vol.30 No.6

Objectives : The best results of treating intracranial aneurysms can be achieved with treating aneurysm before they rupture. Some recent reports about the risk of the bleeding of the unruptured intracranial aneurysm(UIA) being too low(0.05% per year) compared with 1~2% of the previously reported bleeding probability, casts the question about the need for treatment of the UIAs. The purpose of this report is to review the recent reports about the risk of rupture of the UIAs and to assess the morbidity and mortality associated with surgical treatment for UIAs.

지역분석을 위한 시계열 공간연관성 탐색도구

안재성,박기호,이양원,Ahn Jae-Seong,Park Key-Ho,Lee Yang-Won 한국공간정보학회 2006 한국공간정보학회지 Vol.14 No.1

지역분석 기법에서 지리사상의 공간적인 특성을 가장 잘 반영하는 개념 중 하나인 공간연관성은 "모든 것은 다른 모든 것과 연관되어 있지만, 가까운 것은 먼 것보다 더욱 관련이 있다"고 하는 Tobler의 법칙과 그 맥을 같이 한다. 이 연구는 공간통계와 지리적시각화를 결합하여 공간연관성의 시계열 패턴을 탐색적으로 분석하는 지리정보시스템을 개발하는 것을 목적으로 하며, 전역적 및 국지적 공간연관성 분석을 통한 공간현상의 클러스터 탐지나 공간연관성의 시계열 탐색을 통한 사회경제적 변화의 모니터링은 공간정책 투입의 의사결정을 지원하는 수단으로 기능할 수 있다. 전역적 및 국지적 공간연관성을 측정하는 데 반드시 필요한 근린가중치행렬은 행정구역 폴리곤의 기하 및 거리에 기반한 유연한 가중치모형을 구현하여 사용하였으며, 기존의 지리적시각화 기법을 응용 및 개선한 시계열 평행좌표플롯, 시계열 애니메이션지도, 3D 시계열 모란산포도 등을 통해 공간연관성의 시계열 패턴을 효과적으로 표현하였다. 실제 공간현상에 대한 적용 및 평가를 위하여 1995년부터 2004년까지 10년간의 전국 시군구단위 지가변동률 자료를 이용하여 공간연관성의 시계열적 특성을 분석함으로써 시스템의 유용성을 확인하였다. The concept of 'spatial association' explains spatial distribution pattern of geographical phenomenon based on similarity with neighborhoods, as in the Tobler's Law of Geography: 'Everything is related to everything else, but near things are more related than distant things.' In this study, we develop a time-series exploratory analysis tool for discovering temporal patterns of spatial association by combining spatial statistics and geo-visualization, and thus present a possibility to support spatial decision-making process. As for the spatial proximity weight matrix indispensable to measuring global and local spatial association, we employ a variety of flexible weighting schemes using geometric characteristics of areal unit. In addition, we renovate the existing visualization methods for more effective understanding of the procedures and results of time-series analysis on spatial association: for instance, temporal parallel coordinate plot with box plot, animated map for spatial association, and 3D Moran scatterplot. The feasibility of our system is verified by time-series analysis experiments on the spatial association of land price fluctuation rate for all administrative units in Korea, $1995{\sim}2004$.

Ki-67, Proliferating Cell Nuclear Antigen, Flow Cytometry를 이용한 수막종의 증식력 분석

안재성,김정훈,권병덕,Ahn, Jae Sung,Kim, Jeong Hoon,Kwun, Byung Duk 대한신경외과학회 2001 Journal of Korean neurosurgical society Vol.30 No.7

Objective : In this study, we investigated the relationship between the histologic grading of meningiomas and proliferative potentials determined by the Ki-67, proliferating cell nuclear antigen(PCNA) and flow cytometry (FCM) with the aim of determining whether these potentials can be used as a parameter to the proliferative activity, in particular of atypical and malignant meningiomas. Methods : This study consisted of 47 meningiomas(6 malignant, 14 atypical, and random sampled 27 benign meningiomas). By immunohistochemical staining of Ki-67 and PCNA on formalin-fixed, paraffin-embedded sections, the anti-human rabbit polyclonal antibody against Ki-67 antigen and anti-PCNA monoclonal antibody(PC10) scores were counted. FCM was also performed on paraffin-embedded tissue using a selective staining technique for DNA. DNA ploidy, S-phase fraction, and proliferative index(PI)) were determined. Results : The results are summarized as follows ; 1) Proliferation rates as assessed by Ki-67 and PCNA closely correlated with the degree of anaplastic histologic features. 2) Proliferative potentials determined by FCM(S-phase fraction and PI) were not able to distinguish between benign and atypical/malignant meningiomas. 3) DNA ploidy was not a useful indicator of histologic grade in these tumors. 4) Proliferative potentials such as Ki-67 staining index(SI) and PCNA SI did not correlate with the ploidy pattern. 5) There was a linear correlation between Ki-67 SI and PCNA SI, but we could not find a correlation between Ki-67 SI and S-phase fraction or PI. Our results also did not show a statistically signficant correlation between PCNA SI and S-phse fraction or PI. Conclusions : We conclude that evaluation of the proliferative potentials with Ki-67 and PCNA is important as an additional factor for the prediction of malignancy in meningiomas. A dual study of Ki-67 and PCNA SIs on the same tissue might improve the accuracy with which the proliferative potential of a tumor can be predicted. We demonstrated that FCM in meningiomas is not valuable in predicting the behavior of these neoplasms, but we did observe a trend toward more malignancy with higher percent S-phase fraction and higher PI. Analysis of the S-phase fraction and PI might therefore be a useful tool to discriminate among histologic grades of meningiomas.

공공형 임대물류공간 입지적정성 평가체계에 관한 실증 연구

안재성,이승지,김태균,이현주,Ahn, Jaeseong,Lee, Seungji,Kim, Taegyun,Lee, Hyeonjoo 한국토지주택공사 토지주택연구원 2020 LHI journal of land, housing, and urban affairs Vol.11 No.2

In recent years, market access is expected to become more important in logistics location selection. In addition, it is necessary to support logistics functions for small and medium-sized enterprises. In this study, we propose a location suitability evaluation system for public rental logistics spaces. The location selection and evaluation system of the public rental logistics space proposed in this study is composed of large (5), medium (10), and small (20) indicators. The 1^st class were five factors: market factors, economic factors, transportation factors, site factors, policy and social factors, and the 2^nd classifications per the 1^st class, and the 3^rd class for each 2^nd class. After deriving the relative importance of each indicator through AHP for experts, it was verified by utilizing GIS analysis for virtual candidates in the metropolitan area. As a result of the trial application, it was evaluated that it could be applied with realistic results. In addition, it was confirmed that it is possible to apply evaluation indicators using spatial data constructed in Korea, and to use the evaluation indicators, it is necessary to perform various spatial analysis and processing tasks on raw data.

위성 DMB용 2.65GHz 안테나 설계 및 제작

안재성,하덕호,Ahn, Je-Sung,Ha, Deock-Ho 한국정보통신학회 2007 한국정보통신학회논문지 Vol.11 No.12

In this paper, we propose a microstrip antenna with sufficient impedance bandwidths and gains for the 2.65GHz antenna which can be used in the satellite digital multimedia broadcasting. The prposed 2.65GHz satellite DMB bandwidth microstrip antenna is implemented on a substrate, which is small enough to be installed in practical mobile phones, and described simulation feature using by CST MicroWave Studio program. And also, we measured the antenna performance between the proposed antenna and the commercial antenna. From the analysis, it was found that the radiation pattern of proposed antenna is superior to the commercial antenna and an acceptable frequency band is more wider than the existing products. 본 논문에서는 충분한 대역과 이득을 갖는 2.65GHz 위성 DMB 대역의 마이크로 스트립 안테나를 설계 제작하였다. 마이크로 스트립 안테나는 CST MicroWave Studio 프로그램으로 설계하여 시뮬레이션 특성을 기술하고 실제 이동 전화기에 내장 될 수 있도록 충분히 작은 기판에 제작되었다. 또한 실제 제작된 안테나와 상용 안테나의 성능을 비교 측정하였다. 그 결과 본 논문에서 제안한 안테나는 실제 상용화 되고 있는 안테나보다도 방사패턴 성능이 우수하게 나타났고, 이용될 수 있는 대역도 광대역의 특성을 보였다.

비파열 뇌동맥류의 수술적 치료

안재성,권양,권병덕,Ahn, Jae Sung,Kwon, Yang,Kwun, Byung Duk 대한신경외과학회 2000 Journal of Korean neurosurgical society Vol.29 No.3

Objective : The purpose of this report is to assess the morbidity and mortality associated with clipping of intracranial unruptured aneurysms. Methods : At the authors' institution between May 1989 and December 1998, a total of 128 unruptured aneurysms in 110 patients were treated with surgical clippings. The medical records and neuroimaging studies of the patients were reviewed retrospectively. Results : The main locations of the aneurysms were : middle cerebral artery 31%, internal carotid-posterior communicating artery 28%, anterior communicating artery 16%, paraclinoid 6.5%, internal carotid-anterior choroidal artery 7%, posterior circulation 7%. Forty three percent of the aneurysms were symptomatic and 57% asymptomatic. The overall outcome of the surgery was : Glasgow outcome scale(GOS) I 86%, GOS II 6%, GOS III 4.3%, GOS IV 0% and GOS V(death) 3.5%. The operative risk is higher for large to giant aneurysms, and for aneurysms in posterior circulations. Patients with non-giant aneurysm in anterior circulation showed no mortality, but morbidity of 8.2%, and in posterior circulation : 25% of mortality and 75% of morbidity. Patients with giant anterior circulation aneurysm have 22% of mortality and 22% of morbidity. For patients with giant posterior circulation aneurysm, mortality and morbidity were 25% and 25%, respectively. The postoperative deaths were related to occlusion of the major parent artery in 3 cases(75%). The postoperative morbidity was related to occlusion of artery(9/13), intraoperative rupture(3/13), and cranial nerve injury(1/13). Conclusion : This report documents 3.5% mortality and 13% of morbidity in the clipping surgery for unruptured intracranial aneurysms, and the relatively low risk of surgical clipping in non-giant and those located in anterior circulation. The natural history, especially risk of bleeding, of the unruptured intracranial aneurysms is still controversial. However, with respect to surgical results, unruptured non-giant aneurysm located in anterior circulation should be operated in patients with low risk.

원편파의 특성을 이용한 CPCI-OFDM 시스템의 성능평가

안재성(Je-Sung Ahn),황인권(In-Kwon Hwang),하덕호(Deock-Ho Ha) 제어로봇시스템학회 2005 제어로봇시스템학회 합동학술대회 논문집 Vol.2005 No.12