• Title, Summary, Keyword: Scan Time

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The Change of Total Scan Time in Accordance with the Time of the Decision of Scan Time (스캔 시간의 결정시기에 따른 총 스캔 시간 변화에 관한 연구)

  • Lee, Jong-Hun;Ryu, Jae-Kwang;Chung, Woo-Young
    • The Korean Journal of Nuclear Medicine Technology
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    • v.13 no.3
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    • pp.81-85
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    • 2009
  • Purpose: The examination of nuclear medicine observes the change in accordance with the time elapsed in the same region purposed and there are many examinations to acquire the image during the same term. At this time, the same parameter should be applied. The hepatobiliary scan, lung scan etc, are the acquired examination in the divided time with a regular term. Pre-set time that is applied in continued next image is set in order to acquire the fixed counts. The same scan time should be applied for each image. This study will look for the rational plan and analyze the change of scan time in accordance with the time of the decision of scan time at examination that pre-set time is applied. Methods: The hapatobiliary scan that use the radio pharmaceutical $^{99m}Tc$-mebrofenin is choosed as compensation from Jan. 2009 to Mar. 2009 in the department of nuclear medicine in ASAN MEDICAL CENTER. Scan is started after 5 minutes from when 222 MBq (6 mCi) is injected to patient. We let patient stand up between both detectors, and possibly close to the front of detector. When scan time reach 10%, 25%, 50%, 75% of total scan time, we measured the expected total scan time. After finishing all of scan, we compared the total scan time and the expected total scan time, while image is acquiring. and we observed the change of scan time in accordance with radio activity by using phantom. Results: After starting scan, a difference of when scan time reach 10%, 25%, 50%, 75% of total scan time is that the biggest difference is 5 seconds on 10%. There statistically is difference between 25% (t:2.88, p<0.01) and 50% (t:2.05, p<0.01). Conclusions: When the same the scan time is applied in the examination that acquire the many frame, concluding the same scan time has a important effect on a quantitative analysis. Although method that decide the scan time after finish all of the examinations, there is a few problem to apply practical affairs. This may cause an inaccurate result on the examination that need a quantitative analysis. We think that operator should try to improve it. At least, after reach 50% of total scan time, deciding the total scan time mean that you can minimize error of a quantitative analysis caused by unmatched scan time from a gap of image.

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Study of Cure Properties in Photopolymer for Stereolithography using Various Laser Bean Size (레이저빔 직경변화에 대한 광경화성 수지의 경화특성 고찰)

  • 이은덕;김준안;백인환
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.1089-1092
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    • 2001
  • In the stereolithography process, build parameters are laser power, scan velocity, scan width, bean diameter, layer thickness and so on. These values are determined according to product accuracy and build time. Build time can be reduced by improving of scan velocity, laser power, layer thickness, hatching space and so on. But variation of these parameters influence part accuracy, surface roughness, strength. This paper observed cure properties in various beam diameter. In order to examine these, relationships of scan velocity and cure depth, scan velocity and cure width according to various beam diameter in one scan line are measured. And cure thickness is measured according to beam diameter and scan velocity in scan surface of one layer. For reduction of build time, beam diameter and scan velocity is proposed in stereolithography process.

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Optimal Scan time Analysis for Pancreatic Cancer Distinction in Dual time PET-CT Exam (이중시간 PET/CT 검사에서 췌장암 판별을 위한 최적의 Scan time 분석)

  • Chang, Boseok
    • Journal of the Korean Society of Radiology
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    • v.13 no.2
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    • pp.305-311
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    • 2019
  • In this study, present the most useful delay scan time by statistical analysis of SUVm data for 30 suspected pancreatic cancer patients. Two statistical analysis and a mathematical model was applied to the theoretical formula by glucose and insulin mechanics, and a mathematical model was created. Statistical analysis was performed via Metlab p/g. Optimal delay scan time was suggested by Metlab p/g for the change of SUV value over time.In this study, for diagnosis pancreatic cancer by dual time point PET/CT, propose optimal delay scan time 131.5 minuts. The proposed delay scan time showed statistical reliability applicable to the diagnosis of pancreatic cancer (p<0.05). Delayed scanning with the suggested delay scan time of 131.5 minutes is considered to be useful for the diagnosis of pancreatic cancer compared to general PET / CT scan.hen the delayed test is performed with the proposed delay scan time 131.5 minuts, Compared with general PET/CT scans.

Determination of Optimal Scan Time for the Measurement of Downstream Metabolites in Hyperpolarized 13C MRSI

  • Lee, Hansol;Lee, Joonsung;Joe, Eunhae;Yang, Seungwook;Choi, Young-suk;Wang, Eunkyung;Song, Ho-Taek;Kim, Dong-Hyun
    • Investigative Magnetic Resonance Imaging
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    • v.19 no.4
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    • pp.212-217
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    • 2015
  • Purpose: For a single time-point hyperpolarized $^{13}C$ magnetic resonance spectroscopy imaging (MRSI) of animal models, scan-time window after injecting substrates is critical in terms of signal-to-noise ratio (SNR) of downstream metabolites. Pre-scans of time-resolved magnetic resonance spectroscopy (MRS) can be performed to determine the scan-time window. In this study, based on two-site exchange model, protocol-specific simulation approaches were developed for $^{13}C$ MRSI and the optimal scan-time window was determined to maximize the SNR of downstream metabolites. Materials and Methods: The arterial input function and conversion rate constant from injected substrates (pyruvate) to downstream metabolite (lactate) were precalibrated, based on pre-scans of time-resolved MRS. MRSI was simulated using two-site exchange model with considerations of scan parameters of MRSI. Optimal scan-time window for mapping lactate was chosen from simulated lactate intensity maps. The performance was validated by multiple in vivo experiments of BALB/C nude mice with MDA-MB-231 breast tumor cells. As a comparison, MRSI were performed with other scan-time windows simply chosen from the lactate signal intensities of pre-scan time-resolved MRS. Results: The optimal scan timing for our animal models was determined by simulation, and was found to be 15 s after injection of the pyruvate. Compared to the simple approach, we observed that the lactate peak signal to noise ratio (PSNR) was increased by 230%. Conclusion: Optimal scan timing to measure downstream metabolites using hyperpolarized $^{13}C$ MRSI can be determined by the proposed protocol-specific simulation approaches.

Subsequence Matching Under Time Warping in Time-Series Databases : Observation, Optimization, and Performance Results (시계열 데이터베이스에서 타임 워핑 하의 서브시퀀스 매칭 : 관찰, 최적화, 성능 결과)

  • Kim Man-Soon;Kim Sang-Wook
    • The KIPS Transactions:PartD
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    • v.11D no.7
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    • pp.1385-1398
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    • 2004
  • This paper discusses an effective processing of subsequence matching under time warping in time-series databases. Time warping is a trans-formation that enables finding of sequences with similar patterns even when they are of different lengths. Through a preliminary experiment, we first point out that the performance bottleneck of Naive-Scan, a basic method for processing of subsequence matching under time warping, is on the CPU processing step. Then, we propose a novel method that optimizes the CPU processing step of Naive-Scan. The proposed method maximizes the CPU performance by eliminating all the redundant calculations occurring in computing the time warping distance between the query sequence and data subsequences. We formally prove the proposed method does not incur false dismissals and also is the optimal one for processing Naive-Scan. Also, we discuss the we discuss to apply the proposed method to the post-processing step of LB-Scan and ST-Filter, the previous methods for processing of subsequence matching under time warping. Then, we quantitatively verify the performance improvement ef-fects obtained by the proposed method via extensive experiments. The result shows that the performance of all the three previous methods im-proves by employing the proposed method. Especially, Naive-Scan, which is known to show the worst performance, performs much better than LB-Scan as well as ST-Filter in all cases when it employs the proposed method for CPU processing. This result is so meaningful in that the performance inversion among Nive- Scan, LB-Scan, and ST-Filter has occurred by optimizing the CPU processing step, which is their perform-ance bottleneck.

Physical-Aware Approaches for Speeding Up Scan Shift Operations in SoCs

  • Lee, Taehee;Chang, Ik Joon;Lee, Chilgee;Yang, Joon-Sung
    • ETRI Journal
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    • v.38 no.3
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    • pp.479-486
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    • 2016
  • System-on-chip (SoC) designs have a number of flip-flops; the more flip-flops an SoC has, the longer the associated scan test application time will be. A scan shift operation accounts for a significant portion of a scan test application time. This paper presents physical-aware approaches for speeding up scan shift operations in SoCs. To improve the speed of a scan shift operation, we propose a layout-aware flip-flop insertion and scan shift operation-aware physical implementation procedure. The proposed combined method of insertion and procedure effectively improves the speed of a scan shift operation. Static timing analyses of state-of-the-art SoC designs show that the proposed approaches help increase the speeds of scan shift operations by up to 4.1 times that reached under a conventional method. The faster scan shift operation speeds help to shorten scan test application times, thus reducing test costs.

Verification of System using Master-Slave Structure (Master-Slave 기법을 적용한 System Operation의 동작 검증)

  • Kim, In-Soo;Min, Hyoung-Bok
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.1
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    • pp.199-202
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    • 2009
  • Scan design is currently the most widely used structured Design For Testability approach. In scan design, all storage elements are replaced with scan cells, which are then configured as one or more shift registers(also called scan chains) during the shift operation. As a result, all inputs to the combinational logic, including those driven by scan cells, can be controlled and all outputs from the combinational logic, including those driving scan cells, can be observed. The scan inserted design, called scan design, is operated in three modes: normal mode, shift mode, and capture mode. Circuit operations with associated clock cycles conducted in these three modes are referred to as normal operation, shift operation, and capture operation, respectively. In spite of these, scan design methodology has defects. They are power dissipation problem and test time during test application. We propose a new methodology about scan shift clock operation and present low power scan design and short test time.

Analysis on Operation of Anti-Virus Systems with Real-Time Scan and Batch Scan (실시간스캔과 배치스캔을 갖춘 안티바이러스시스템의 운영 분석)

  • Yang, Won Seok;Kim, Tae-Sung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38B no.11
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    • pp.861-869
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    • 2013
  • We consider an information system where viruses arrive according to a Poisson process with rate ${\lambda}$. The information system has two types of anti-virus operation policies including 'real-time scan' and 'batch scan.' In the real-time scan policy, a virus is assumed to be scanned immediately after its arrival. Consequently, the real-time scan policy assumes infinite number of anti-viruses. We assume that the time for scanning and curing a virus follows a general distribution. In the batch scan policy, a system manager operates an anti-virus every deterministic time interval and scan and cure all the viruses remaining in the system simultaneously. In this paper we suggest a probability model for the operation of anti-virus software. We derive a condition under which the operating policy is achieved. Some numerical examples with various cost structure are given to illustrate the results.

Selective Segment Bypass Scan Architecture for Test Time and Test Power Reduction (테스트 시간과 테스트 전력 감소를 위한 선택적 세그먼트 바이패스 스캔 구조)

  • Yang, Myung-Hoon;Kim, Yong-Joon;Park, Jae-Seok;Kang, Sung-Ho
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.46 no.5
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    • pp.1-8
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    • 2009
  • Since scan based testing is very efficient and widely used for testing large sequential circuits. However, since test patterns are serially injected through long scan chains, scan based testing requires very long test application time. Also, compared to the normal operations, scan shifting operations drastically increase power consumption. In order to solve these problems, this paper presents a new scan architecture for both test application time and test power reduction. The proposed scan architecture partitions scan chains into several segments and bypasses some segments which do not include any specified bit. Since bypassed segments are excluded from the scan shifting operation, the test application time and test power can be significantly reduced.

New Driving Method for Fast Addressing of AC-Plasma Display Panel

  • Kim, Gun-Su;Choi, Hoon-Young;Lee, Seok-Hyun;Seo, Jeong-Hyun
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.726-729
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    • 2003
  • A new driving method is proposed to reduce the address period. The scan time of new driving method overlaps with the next scan time during the discharge lag time. Thus, without reducing the address pulse width and the scan pulse width, the new addressing method can reduce the address period. The results show that the scan time of about 100ns ${\sim}$ 300ns can be overlapped without the misfiring,.

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