상용차 기반에 대한 주차보조시스템 사용자 감성 평가

전재석(Jaeseok Jeon),박현배(Hyunbae Park),문희석(Heeseok Moon),곽수진(Sujin Kwag) 한국자동차공학회 2013 한국자동차공학회 부문종합 학술대회 Vol.2013 No.5

In this paper, we described about evaluation of human sensibility using park assist system of the commercial vehicle. The perpendicular parking and parallel parking have been carried out as a user test and subjects are classified as beginning drivers, drivers with less than 1 year experience and over 3 years experience. As a result, parking duration of beginning drivers and drivers with less than 1 year experience who use automatic parking assistance system is similar to drivers with over 3 years experience. However error occurred according to sensor position and distance between vehicle and parking space. And also it occurred that the vehicle leaves from parking line or does not recognize the parking space. Therefore, if we improve its completeness by compensating problems that came up from this evaluation and distribute the automatic parking assistance system, it is expected that the park assistance system is to help driver providing convenience of parking.

우주분야 선행연구개발 기획을 위한 우주수송 관련 과제의 도출

박광근(Kwangkun Park),임석희(Seokhee Lim),유재석(Jaeseok Yoo),이금오(Keumoh Lee),박재성(Jaesung Park),오상관(Sanggwan Oh),박순영(Soonyoung Park),박용규(Yongkyu Park),임하영(Hayoung Lim),김주완(Juwan Kim),고주용(Jooyong Koh),황수설(Soose 한국추진공학회 2018 한국추진공학회 학술대회논문집 Vol.2018 No.12

Single-Slab 3D Fast Spin Echo Imaging: T1-Contrast Perspective

Park Jaeseok 대한자기공명의과학회 2023 Investigative Magnetic Resonance Imaging Vol.27 No.3

Fast spin echo (FSE) in magnetic resonance imaging has long been a main workhorse in clinical routines due to its versatile image contrast and robustness in improving magnetic field inhomogeneities. Nevertheless, the conventional high flip angle strategy limits its imaging efficiency, including high energy deposition to subjects, prolonged imaging time due to a necessarily short echo train, and substantial signal modulation along the echo train. Particularly, achieving high resolution T1-weighted imaging within a reasonable imaging time is challenging due to a very short echo train. In this review, we introduce T1- optimized single-slab 3D FSE imaging with variable refocusing flip angles as a promising solution to the above problems with its clinical applications. We provide a general description of a single-slab 3D pulse sequence and introduce its T1-optimized version with the required configuration of radio frequency and gradient pulses. Subsequently, the T1- weighted single-slab 3D FSE is investigated for signal evolution along the echo train, image contrasts, and flow sensitivity. Given the characteristics of high T1-weighted contrast and flow sensitivity, we demonstrate the clinical application of the single-slab 3D FSE, including high resolution structural imaging, as an alternative to conventional magnetization prepared spoiled gradient echo, highly tumor-targeted contrast-enhanced imaging for efficient detection of small metastases, and high-resolution vessel wall imaging for stroke diagnosis.

An Effective Programmable Memory BIST for Embedded Memory

PARK, Youngkyu,PARK, Jaeseok,HAN, Taewoo,KANG, Sungho The Institute of Electronics, Information and Comm 2009 IEICE transactions on information and systems Vol.92 No.12

<P>This paper proposes a micro-code based Programmable Memory BIST (PMBIST) architecture that can support various kinds of test algorithms. The proposed Non-linear PMBIST (NPMBIST) guarantees high flexibility and high fault coverage using not only March algorithms but also non-linear algorithms such as Walking and Galloping. This NPMBIST has an optimized hardware overhead, since algorithms can be implemented with the minimum bits by the optimized instructions. Finally, various and complex algorithms can be run thanks to its support of multi-loop.</P>

Phase‐sensitive, dual‐acquisition, single‐slab, 3D, turbo‐spin‐echo pulse sequence for simultaneous <i>T</i>₂‐weighted and fluid‐attenuated whole‐brain imaging

Park, Jaeseok,Park, Suhyung,Yeop Kim, Eung,Suh, Jin‐,Suck Wiley Subscription Services, Inc., A Wiley Company 2010 Magnetic resonance in medicine Vol.63 No.5

<P><B>Abstract</B></P><P>Conventional <I>T</I><SUB>2</SUB>‐weighted turbo/fast spin echo imaging is clinically accepted as the most sensitive method to detect brain lesions but generates a high signal intensity of cerebrospinal fluid (CSF), yielding diagnostic ambiguity for lesions close to CSF. Fluid‐attenuated inversion recovery can be an alternative, selectively eliminating CSF signals. However, a long time of inversion, which is required for CSF suppression, increases imaging time substantially and thereby limits spatial resolution. The purpose of this work is to develop a phase‐sensitive, dual‐acquisition, single‐slab, three‐dimensional, turbo/fast spin echo imaging, simultaneously achieving both conventional <I>T</I><SUB>2</SUB>‐weighted and fluid‐attenuated inversion recovery–like high‐resolution whole‐brain images in a single pulse sequence, without an apparent increase of imaging time. Dual acquisition in each time of repetition is performed, wherein an in phase between CSF and brain tissues is achieved in the first acquisition, while an opposed phase, which is established by a sequence of a long refocusing pulse train with variable flip angles, a composite flip‐down restore pulse train, and a short time of delay, is attained in the second acquisition. A CSF‐suppressed image is then reconstructed by weighted averaging the in‐ and opposed‐phase images. Numerical simulations and in vivo experiments are performed, demonstrating that this single pulse sequence may replace both conventional <I>T</I><SUB>2</SUB>‐weighted imaging and fluid‐attenuated inversion recovery. Magn Reson Med 63:1422–1430, 2010. © 2010 Wiley‐Liss, Inc.</P>

Contrast-enhanced, three-dimensional, whole-brain, black-blood imaging: Application to small brain metastases

Park, Jaeseok,Kim, Eung Yeop Wiley Subscription Services, Inc., A Wiley Company 2010 Magnetic resonance in medicine Vol.63 No.3

<P>Contrast-enhanced three-dimensional T<SUB>1</SUB>-weighted imaging based on magnetization-prepared rapid-gradient recalled echo is widely used for detecting small brain metastases. However, since contrast materials remain in both blood and the tumor parenchyma and thus increase the signal intensity of both regions, it is often challenging to distinguish brain tumors from blood. In this work, we develop a T<SUB>1</SUB>-weighted, black-blood version of single-slab three-dimensional turbo/fast spin echo whole-brain imaging, in which the signal intensity of the brain tumor is selectively enhanced while that of blood is suppressed. For blood suppression, variable refocusing flip angles with flow-sensitizing gradients are employed. To avoid a signal loss resulting from the flow-sensitizing scheme, the first refocusing flip angle is forced to 180°. Composite restore pulses at the end of refocusing pulse train are applied to achieve partial inversion recovery for the T<SUB>1</SUB>-weighted contrast. Simulations and in vivo volunteer and patient experiments are performed, demonstrating that this approach is highly efficient in detecting small brain metastases. Magn Reson Med 63:553–561, 2010. © 2010 Wiley-Liss, Inc.</P>

Prediction of the Fundamental Mode Lamb Wave Reflection from a Crack-Like Discontinuity Using Eigen-Mode Expansion

Jaeseok Park,Chang Heui Jang,Jong Po Lee 한국비파괴검사학회 2010 한국비파괴검사학회지 Vol.30 No.3

Based on the idea of eigen-mode expansion, a method to analyze the reflection of Lamb wave from a finite vertical discontinuity of plate is theoretically derived and verified by experiment. The theoretical prediction is in good agreement with the experimental result, and this strongly suggests that eigen-mode expansion method could be used for solution of inverse scattering problem for ultrasonic testing using Lamb wave.

Detection of Small Metastatic Brain Tumors: Comparison of 3D Contrast-Enhanced Whole-Brain Black-Blood Imaging and MP-RAGE Imaging

Park, Jaeseok,Kim, Jinna,Yoo, Eunhye,Lee, Hyunyeol,Chang, Jong-Hee,Kim, Eung Yeop Lippincott Williams Wilkins, Inc. 2012 Vol. No.

OBJECTIVE:: Early and accurate diagnosis of small metastatic brain tumors may affect outcomes and treatment strategies. For this reason, 3-dimensional (3D) thin-section imaging is preferred. However, with conventional contrast-enhanced (CE) 3D imaging, such as magnetization-prepared rapid gradient echo (MP-RAGE), many visually enhanced vessels may mimic small metastatic tumors, hindering tumor detection. CE black-blood single-slab 3D turbo-spin echo imaging (BB-ssTSE) was recently developed, which uses variable refocusing flip angles and flow-sensitizing gradient schemes, to enhance metastatic brain tumors while selectively suppressing blood vessels. The purpose of this work was to investigate the efficiency of the proposed CE BB-ssTSE in detecting small metastatic brain tumors as compared with conventional MP-RAGE. MATERIALS AND METHODS:: Numerical comparisons of MP-RAGE and BB-ssTSE were performed by simulation studies to investigate the signal/contrast behaviors of flowing blood and stationary CE tumors. For in vivo studies, we enrolled 35 patients (18 women; mean age, 58.1 years) with breast or lung cancer who underwent brain magnetic resonance imaging. After administering a double dose of contrast medium, whole-brain 2-dimensional T1-weighted imaging followed by high-resolution isotropic 3D BB-ssTSE and MP-RAGE was performed at 3.0 T. Two reviewers independently evaluated the presence of metastatic brain tumors using: (1) MP-RAGE; (2) BB-ssTSE; and (3) MP-RAGE + BB-ssTSE sequentially in 3 review sessions, 2 weeks apart. The lesions were classified by size into 2 groups: large (≥5 mm) and small (<5 mm). Both reviewers marked all tumors detected at each session. Another reviewer combined the results of the 2 reviewers and compared the detection rates of metastatic brain tumors between BB-ssTSE and MP-RAGE by using follow-up imaging. Intraclass correlation coefficients between the 2 reviewers were measured. RESULTS:: Numerical simulations showed that the proposed BB-ssTSE effectively attenuated the signal intensity of flowing blood over the entire echo train, resulting in CE tumor-to-white matter contrast comparable with conventional MP-RAGE. The combined evaluation of MP-RAGE + BB-ssTSE showed 242 tumors in 28 patients. Of these, 153 lesions were <5 mm. MP-RAGE found 111 small metastatic brain tumors, BB-ssTSE found 150, and MP-RAGE + BB-ssTSE found 153. Significantly, more small tumors were detected by BB-ssTSE than MP-RAGE (P = 0.001, Wilcoxon signed-rank test). All large tumors were detected similarly by both MP-RAGE and BB-ssTSE. By combined results for MP-RAGE + BB-ssTSE, sensitivities for detection of small metastatic tumors were 72.5% for MP-RAGE and 98.0% for BB-ssTSE (P < 0.0001, McNemar test). Intraclass correlation coefficients between the 2 reviewers were 0.826 for MP-RAGE and 0.954 for BB-ssTSE. CONCLUSION:: Compared with conventional MP-RAGE, the proposed CE BB-ssTSE imaging, which enhances tumors while selectively suppressing blood vessels, leads to significantly better detection of small metastatic brain tumors <5 mm.

FRESH: A New Test Result Extraction Scheme for Fast TSV Tests

Park, Jaeseok,Lim, Hyunyul,Kang, Sungho IEEE 2017 IEEE transactions on computer-aided design of inte Vol.36 No.2

<P>Three-dimensional integrated circuits (3-D ICs) are considered to meet the performance needs of future ICs. The core components of 3-D ICs are through-silicon vias (TSVs), which should pass appropriate prebond and post-bond tests in 3-D IC fabrication processes. The test inputs must be injected into the TSVs, and the test results must be extracted. This paper proposes a new test result extraction scheme [ fast result extraction by selective shift-out (FRESH)] for prebond and post-bond TSV testing. With additional hardware, the proposed scheme remarkably reduces the TSV test time. FRESH avoids unnecessary test result extraction when the number of faulty TSVs in the TSV set is 0 or exceeds the number of TSV redundancies in the set. These early fault analyses are executed in the checkers of TSV groups. The experimental results show that the proposed scheme can reduce the result extraction time in practical environments.</P>

Adaptive self‐calibrating iterative GRAPPA reconstruction

Park, Suhyung,Park, Jaeseok Wiley Subscription Services, Inc., A Wiley Company 2012 Magnetic resonance in medicine Vol.67 No.6

<P><B>Abstract</B></P><P>Parallel magnetic resonance imaging in <I>k</I>‐space such as generalized auto‐calibrating partially parallel acquisition exploits spatial correlation among neighboring signals over multiple coils in calibration to estimate missing signals in reconstruction. It is often challenging to achieve accurate calibration information due to data corruption with noises and spatially varying correlation. The purpose of this work is to address these problems simultaneously by developing a new, adaptive iterative generalized auto‐calibrating partially parallel acquisition with dynamic self‐calibration. With increasing iterations, under a framework of the Kalman filter spatial correlation is estimated dynamically updating calibration signals in a measurement model and using fixed‐point state transition in a process model while missing signals outside the step‐varying calibration region are reconstructed, leading to adaptive self‐calibration and reconstruction. Noise statistic is incorporated in the Kalman filter models, yielding coil‐weighted de‐noising in reconstruction. Numerical and in vivo studies are performed, demonstrating that the proposed method yields highly accurate calibration and thus reduces artifacts and noises even at high acceleration. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.</P>