• 제목/요약/키워드: time-clipping

검색결과 101건 처리시간 0.026초

Management of Recurrent Cerebral Aneurysm after Surgical Clipping : Clinical Article

  • Kim, Pius;Jang, Suk Jung
    • Journal of Korean Neurosurgical Society
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    • 제61권2호
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    • pp.212-218
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    • 2018
  • Objective : Surgical clipping of the cerebral aenurysm is considered as a standard therapy with endovascular coil embolization. The surgical clipping is known to be superior to the endovascular coil embolization in terms of recurrent rate. However, a recurrent aneurysm which is initially treated by surgical clipping is difficult to handle. The purpose of this study was to research the management of the recurrent cerebral aneurysm after a surgical clipping and how to overcome them. Methods : From January 1996 to December 2015, medical records and radiologic findings of 14 patients with recurrent aneurysm after surgical clipping were reviewed retrospectively. Detailed case-by-case analysis was performed based on preoperative, postoperative and follow-up radiologic examinations and operative findings. All clinical variables including age, sex, aneurysm size and location, type and number of applied clips, prognosis, and time to recurrence are evaluated. All patients are classified by causes of the recurrence. Possible risk factors that could contribute to those causes and overcoming ways are comprehensively discussed. Results : All recurrent aneurysms after surgical clipping were 14 of 2364 (0.5%). Three cases were males and 11 cases were females. Mean age was 52.3. At first treatment, nine cases were ruptured aneurysms, four cases were unruptured aneurysms, and one case was unknown. Locations of recurrent aneurysm were determined; anterior communicating artery (A-com) (n=7), posterior communicating artery (P-com) (n=3), middle cerebral artery (n=2), anterior cerebral artery (n=1) and basilar artery (n=1). As treatment of the recurrence, 11 cases were treated by surgical clipping and three cases were treated by endovascular coil embolization. Three cases of all 14 cases occurred in a month after the initial treatment. Eleven cases occurred after a longer interval, and three of them occurred after 15 years. By analyzing radiographs and operative findings, several main causes of the recurrent cerebral aneurysm were found. One case was incomplete clipping, five cases were clip slippage, and eight cases were fragility of vessel wall near the clip edge. Conclusion : This study revealed main causes of the recurrent aneurysm and contributing risk factors to be controlled. To manage those risk factors and ultimately prevent the recurrent aneurysm, neurosurgeons have to be careful in the technical aspect during surgery for a complete clipping without a slippage. Even in a perfect surgery, an aneurysm may recur at the clip site due to a hemodynamic change over years. Therefore, all patients must be followed up by imaging for a long period of time.

Fast Time-Scale Modification of Speech Using Nonlinear Clipping Methods

  • 정호영;김형순;이성주
    • 대한음성학회지:말소리
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    • 제59호
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    • pp.69-87
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    • 2006
  • Among the conventional time-scale modification (TSM) methods, the synchronized overlap and add (SOLA) method is widely used due to its good performance relative to computational complexity But the SOLA method remains complex due to its synchronization procedure using the normalized cross-correlation function. In this paper, we introduce a computationally efficient SOLA method utilizing 3 level center clipping method, as well as zero-crossing and level-crossing information. The result of subjective preference test indicates that the proposed method can reduce the computational complexity by over 80% compared with the conventional SOLA method without serious degradation of synthesized speech quality.

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Unruptured Intracranial Aneurysms with Oculomotor Nerve Palsy : Clinical Outcome between Surgical Clipping and Coil Embolization

  • Nam, Kyoung-Hyup;Choi, Chang-Hwa;Lee, Jae-Il;Ko, Jun-Gyeong;Lee, Tae-Hong;Lee, Sang-Weon
    • Journal of Korean Neurosurgical Society
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    • 제48권2호
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    • pp.109-114
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    • 2010
  • Objective : To evaluate the clinical outcome of coil embolization for unruptured intracranial aneurysm (UIA) with oculomotor nerve palsy (ONP) compared with surgical clipping. Methods : A total of 19 patients presented with ONP caused by UIAs between Jan 2004 and June 2008. Ten patients underwent coil embolization and nine patients surgical clipping. The following parameters were retrospectively analyzed to evaluate the differences in clinical outcome observed in both coil embolization and surgical clipping : 1) gender, 2) age, 3) location of the aneurysm, 4) duration of the symptom, and 5) degree of ONP. Results : Following treatment, complete symptomatic recovery or partial relief from ONP was observed in 15 patients. Seven of the ten patients were treated by coil embolization, compared to eight of the nine patients treated by surgical clipping (p = 0.582). Patient's gender, age, location of the aneurysm, size of the aneurysm, duration of symptom, and degree of the ONP did not statistically correlate with recovery of symptoms between the two groups. No significant differences were observed in mean improvement time in either group (55 days in coil embolization and 60 days in surgical clipping). Conclusion : This study indicates that no significant differences were observed in the clinical outcome between coil embolization and surgical clipping techniques in the treatment of aneurysms causing ONP. Coil embolization seems to be more feasible and safe treatment modality for the relief and recovery of oculomotor nerve palsy.

이탈리안라이그라스 예취시기가 종자 등숙 및 발아에 미치는 영향 (Effect of Clipping Time on Seed Maturity and Germination in Italian Ryegrass (Lolium multiflorum Lam. Italicum))

  • 서석기;김영두;박호기;박문수
    • 한국작물학회지
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    • 제42권1호
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    • pp.104-111
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    • 1997
  • 이탈리안라이그라스의 청초 이용 및 종자 생산가능성을 검토코자 1986년 10월부터 이듬해 6월까지 Tetrone 등 7품종을 공시하여 예취시기를 각각 4월 10일 예취와 4월 30일 예취 및 무예취로하여 시험을 실시한 결과를 요약하면 다음과 같다. 1. 출수기는 K-11, T.N.T 등 품종이 늦었는데 각 품종 모두 예취시기가 늦을수록 출수기가 지연되고, 천입종은 직선적으로 감소하였다. 2. 입형은 입장, 입폭 및 입후 모두 무예취구에 비하여 예취시기가 늦을수록 작아지는 경향이며, 품종간에는 4배체 품종들이 2배체 품종들 보다 컸다. 3. 최초 발아율 및 발아세는 $25^{\circ}C$에서 15$^{\circ}C$ 보다 높았으며, 최종 발아율은 예취시기가 늦어질수록 낮았는데, 온도간에는 15$^{\circ}C$$25^{\circ}C$보다 다소 높았으며, 품종간에는 출수기가 빨랐던 품종들의 발아율이 높았다. 4. 발아 균일도는 $25^{\circ}C$가 15$^{\circ}C$보다 다소 좋았으며, 예취시기가 늦어질수록 낮아졌는데, 품종간에는 K-11 등 출수기가 빨랐던 것들이 발아가 균일 한 경향이며, 평균 발아일수는 $25^{\circ}C$보다 15$^{\circ}C$에서 길었고, 예취가 늦을수록 길었다. 5. 등숙관련 형질과 발아율 관계는 예취가 늦어질수록 출수가 늦어 발아율은 직선적으로 낮아지고, 천입종이 무거울수록 발아율이 높아지는 경향이었다.

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OFDM 시스템에서 시간 및 주파수 영역 클리핑의 Total Degradation 성능평가 (Total Degradation Performance Evaluation of the Time- and Frequency-Domain Clipping in OFDM Systems)

  • 한창식;서만중;임성빈
    • 대한전자공학회논문지TC
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    • 제44권7호통권361호
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    • pp.17-22
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    • 2007
  • OFDM (Orthogonal Frequency Division Multiplexing)시스템은 다수 반송파 전송의 특수한 형태로 볼 수 있으며 하나의 데이터열이 보다 낮은 데이터 전송률을 갖는 부반송파를 통해 전송된다. OFDM을 사용하는 중요한 이유 중 하나는 OFDM을 사용하면 주파수 선택적 페이딩이나 협대역 간섭에 대한 강건함이 증가하기 때문이다. 하지만, 시간 영역 OFDM 신호는 독립적으로 변조된 많은 부반송파들로 구성되므로 이들이 동위상으로 더해질 때 신호의 진폭이 증가하여 PAPR (Peak-to-Average Power Ratio)이 증가된다. 본 논문에서는 수신단의 구조에 변화를 주지 않으며 또한 추가적인 정보의 전송이 필요 없이 기존 수신기를 그대로 사용할 수 있는 PAPR 감소기법의 성능을 평가하였다. 이 방법은 에러 벡터 크기 (Error Vector Magnitude; EVM) 내에서 시간 영역과 주파수 영역 신호에 대하여 클리핑을 사용한 것으로 기존의 최적화 방법과 비교하여 계산량의 복잡도가 낮다. 이 기법을 비선형 증폭기를 사용하는 OFDM 시스템에서 평가하였다. 모의실험 결과, 시간 및 주파수 영역 클리핑 기반의 PAPR 감소기법은 TD (Total Degradation)관점에서 전력효율이 향상되며 증폭기의 비선형 왜곡의 영향을 줄이는 효과가 있음을 확인할 수 있었다.

OFDM 시스템에서 PAPR기 감소와 고속처리를 위한 새로운 적응형 PTS 기법의 성능분석 (Performance Analysis of a New Adaptive PTS Scheme for Reducing the PAPR and High Speed Processing in OFDM Systems)

  • 채주호;임연주;박상규
    • 한국통신학회논문지
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    • 제28권9A호
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    • pp.710-716
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    • 2003
  • OFDM(Orthogonal Frequency Division Multiplexing)은 주파수 이용효율을 높이고 고속의 데이터 전송이 가능하며 주파수 선택적 페이딩에 강한 전송 방식이지만, 다수 부반송파(sub-carrier)들의 중첩현상으로 인해 전송 신호의 PAPR(Peak to Average Power Ratio)이 크다는 문제점이 있다. 본 논문에서는 PAPR의 감소와 PAPR의 연산량 감소를 위해, PTS 기법에 clipping 개념을 적용하여 두개의 임계 레벨을 갖는 적응형 PTS(Partial Transmit Sequence) 기법을 제안한다. 모의실험을 통해, 제안한 기법이 만족할 만한 BER(Bit Error Rate) 성능을 유지하면서 clipping delta 값(Δ)을 1dB, 2dB 그리고 3dB로 증가 할수록 clipping 개념이 없는 기존의 적응형 PTS 기법보다 PAPR의 연산량을 크게 줄임으로써 시스템의 데이터 처리 속도면에서 우수한 성능을 가짐을 보인다.

다각형 클리핑 알고리즘(Polygon Clipping Algorithm)을 이용한 배구경기 분석 프로그램 개발 (Development of Volleyball Match Analysis Program through Polygon Clipping Algorithm)

  • 홍성진;이기청
    • 한국운동역학회지
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    • 제23권1호
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    • pp.45-51
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    • 2013
  • The current study developed the analysis program by employing the Polygon Clipping Algorithm to calculate the open area on the court when players try to spike a ball. The program consists of two kinds of output screen. First, on the main output screen, it is possible to calculate both blocked area by net and blockers, and opened area to avoid the blocked area when players spike the ball. Additionally, the secondary output screen shows the moving path of setter and the location of set. Main output screen indicates hitting points of spiking, blocking, and open area. Also, it is possible to analyze the movement of setter, location of set, and hitting point of attacker. The program was tested by comparing real coordinate value and location coordinate value which is operated on the program. To apply this program in the field, future study needs to develop the program that can calculate three dimensions coordinate fast by tracking the location of players or ball in real time.

Comparison between Lateral Supraorbital Approach and Pterional Approach in the Surgical Treatment of Unruptured Intracranial Aneurysms

  • Cha, Ki-Chul;Hong, Seung-Chyul;Kim, Jong-Soo
    • Journal of Korean Neurosurgical Society
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    • 제51권6호
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    • pp.334-337
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    • 2012
  • Objective : The lateral supraorbital (LSO) approach is a modified method of the classic pterional approach and it has advantages of short skin incision and small craniotomy compared with the pterional approach. This study was designed to compare the two approaches in the surgical treatment of unruptured intracranial aneurysms. Methods : We retrospectively reviewed 122 patients with 137 unruptured intracranial aneurysms treated by clipping, from July 2009 to April 2011. Between August 2010 and April 2011, 61 patients were treated by clipping via the lateral supraorbital approach and the same number of patients treated by clipping via the pterional approach were retrospectively enrolled. We analyzed the two groups and compared demographic, radiologic and clinical variables. Results : The mean age of patients in the two groups was 54.6 years (LSO group) and 55.7 years (Pterion group). The mean duration of hospitalization was shorter in the LSO group than in the Pterion group (7.9 days vs. 9.0 days, p=0.125) and the mean operation time was also significantly shorter in the LSO group (117.1 minutes vs. 164.3 minutes, p<0.001). Furthermore, the mean craniotomy area was much smaller in the LSO group (1275.4 $mm^2$ vs. 2858.9 $mm^2$, p<0.001). The two groups showed similar distributions of aneurysm location and postoperative complications. Conclusion : The lateral supraorbital approach for the clipping of unruptured intracranial aneurysm could be a good alternative to the classic pterional approach.

Characteristics and Management of Residual or Slowly Recurred Intracranial Aneurysms

  • Ihm, Eun-Hyun;Hong, Chang-Ki;Shim, Yu-Shik;Jung, Jin-Young;Joo, Jin-Yang;Park, Seoung-Woo
    • Journal of Korean Neurosurgical Society
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    • 제48권4호
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    • pp.330-334
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    • 2010
  • Objective : Residual aneurysm from incomplete clipping or slowly recurrent aneurysm is associated with high risk of subarachnoid hemorrhage. We describe complete treatment of the lesions by surgical clipping or endovascular treatment. Methods : We analyzed 11 patients of residual or recurrent aneurysms who had undergone surgical clipping from 1998 to 2009. Among them, 5 cases were initially clipped at our hospital. The others were referred from other hospitals after clipping. The radiologic and medical records were retrospectively analyzed. Results : All patients presented with subarachnoid hemorrhage at first time, and the most frequent location of the ruptured residual or recurrent aneurysm was in the anterior communicating artery to posterior-superior direction. Distal anterior cerebral artery, posterior communicating artery, and middle cerebral artery was followed. Repositioning of clipping in eleven cases, and one endovascular treatment were performed. No residual aneurysm was found in postoperative angiography, and no complication was noted in related to the operations. Conclusion : These results indicate the importance of postoperative or follow up angiography and that reoperation of residual or slowly recurrent aneurysm should be tried if such lesions being found. Precise evaluation and appropriate planning including endovascular treatment should be performed for complete obliteration of the residual or recurrent aneurysm.

크리핑 벤트그라스 훼어웨이에서 관수회수.예지물과 질소시비수준이 엽조직 및 토양 질소함유량에 미치는 효과 (A Three-year Study on the Leaf and Soil Nitrogen Contents Influenced by Irrigation Frequency, Clipping Return or Removal and Nitrogen Rate in a Creeping Bentgrass Fairway)

  • 김경남;로버트쉬어만
    • 아시안잔디학회지
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    • 제11권2호
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    • pp.105-115
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    • 1997
  • Responses of 'Penncross' creeping bentgrass turf to various fairway cultural practices are not well-established or supported by research results. This study was initiated to evaluate the effects of irrigation frequency, clipping return or removal, and nitrogen rate on leaf and soil nitrogen con-tent in the 'Penncross' creeping bentgrass (Agrostis palustris Huds.) turf. A 'Penncross' creeping bentgrass turf was established in 1988 on a Sharpsburg silty-clay loam (Typic Argiudoll). The experiment was conducted from 1989 to 1991 under nontraffic conditions. A split-split-plot experimental design was used. Daily or biweekly irrigation, clipping return or removal, and 5, 15, or 25 g N $m-^2$ $yr-^1$ were the main-, sub-, and sub-sub-plot treatments, respectively. Treatments were replicated 3 times in a randomized complete block design. The turf was mowed 4 times weekly at a l3 mm height of cut. Leaf tissue nitrogen content was analyzed twice in 1989 and three times in both 1990 and 1991. Leaf samples were collected from turfgrass plants in the treatment plots, dried immediately at 70˚C for 48 hours, and evaluated for total-N content, using the Kjeldahl method. Concurrently, six soil cores (18mm diam. by 200 mm depth) were collected, air dried, and analyzed for total-N content. Nitrogen analysis on the soil and leaf samples were made in the Soil and Plant Analyical Laboratory, at the University of Nebraska, Lincoln, USA. Data were analyzed as a split-split-plot with analysis of variance (ANOVA), using the General Linear Model procedures of the Statistical Analysis System. The nitrogen content of the leaf tissue is variable in creeping bentgrass fairway turf with clip-ping recycles, nitrogen application rate and time after establishment. Leaf tissue nitrogen content increased with clipping return and nitrogen rate. Plots treated with clipping return had 8% and 5% more nitrogen content in the leaf tissue in 1989 and 1990, respectively, as compared to plots treated with clipping removal. Plots applied with high-N level (25g N $m-^2$ $yr-^1$)had 10%, 17%, and 13% more nitrogen content in leaf tissue in 1989, 1990, and 1991, respectively, when compared with plots applied with low-N level (5g N $m-^2$ $yr-^1$). Overall observations during the study indicated that leaf tissue nitrogen content increased at any nitrogen rate with time after establishment. At the low-N level treatment (5g N $m-^2$ $yr-^1$ ), plots sampled in 1991 had 15% more leaf nitrogen content, as compared to plots sampled in 1989. Similar responses were also found from the high-N level treatment (25g N $m-^2$ $yr-^1$ ).Plots analyzed in 1991 were 18% higher than that of plots analyzed in 1989. No significant treatment effects were observed for soil nitrogen content over the first 3 years after establishment. Strategic management application is necessary for the golf course turf, depending on whether clippings return or not. Different approaches should be addressed to turf fertilization program from a standpoint of clipping recycles. It is recommended that regular analysis of the soil and leaf tissue of golf course turf must be made and fertilization program should be developed through the interpretation of its analytic data result. In golf courses where clippings are recycled, the fertilization program need to be adjusted, being 20% to 30% less nitrogen input over the clipping-removed areas. Key words: Agrostis palustris Huds., 'Penncross' creeping bentgrass fairway, Irrigation frequency, Clipping return, Nitrogen rate, Leaf nitrogen content, Soil nitrogen content.

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