플래시 변환 계층에 대한 TPC-C 벤치마크를 통한 성능분석 (pp.201-205)

박성환(Sunghwan Park),장주연(Juyeon Jang),서영주(Youngju Suh),박원주(Wonjoo Park),박상원(Sangwon Park) 한국정보과학회 2008 정보과학회 컴퓨팅의 실제 논문지 Vol.14 No.2

최근 플래시 메모리는 소형 정보기기의 주된 저장매체로서 그 사용이 급격히 증가하고 있다. 또한, 플래시메모리의 용량이 점점 증가함에 따라 더욱 많은 정보를 저장하고 관리하려는 시도가 이루어지고 있다. 따라서 효율적으로 정보를 관리하는 시스템인 데이타베이스가 플래시 메모리에서도 필요로 하게 되었다. 그러나 데이타베이스는 임의적인 디스크 I/O를 발생시키는 특징이 있어 현재의 플래시 메모리 시스템에서 그 성능이 매우 좋지 않다. 본 논문에서는 이러한 문제점을 고찰하고자 기존의 FTL 알고리즘들이 플래시 기반의 데이타베이스 시스템에서 어떠한 성능을 보이는지 실험하였다. 그 결과 실험에 사용한 FTL 알고리즘 모두가 매우 좋지 않은 성능을 보였다. 특히 지금까지 상당히 좋은 FTL 알고리즘으로 평가되었던 것들이 데이타베이스 응용에서는 나쁜 성능을 보였다. 또한 현재 플래시 메모리의 성능을 개선하고자 사용되는 칩 인터리빙 기술 또한 모든 FTL 알고리즘에서 좋은 성능을 내지 못하였다. 본 논문에서는 실험 결과를 바탕으로 데이타베이스 시스템을 잘 지원하는 새로운 FTL 알고리즘이 필요한 이유와 그 방향을 제시한다. The flash memory is widely used as a main storage of embedded devices. It is adopted as a storage of database as growing the capacity of the flash memory. We run TPC-C benchmark on various FTL algorithms. But, the database shows poor performance on flash memory because the characteristic of I/O requests is full random. In this paper, we show the performance of all existing FTL algorithms is very poor. Especially, the FTL algorithm known as good at small mobile equipment shows worst performance. In addition, the chip-inter-leaving which is a technique to improve the performance of the flash memory doesn't work well. In this paper, we inform you the reason that we need a new FTL algorithm and the direction for the database in the future.

Broadband CMOS Stacked RF Power Amplifier Using Reconfigurable Interstage Network for Wideband Envelope Tracking

Sunghwan Park,Jung-Lin Woo,Unha Kim,Youngwoo Kwon Professional Technical Group on Microwace Theory a 2015 IEEE Transactions on Microwave Theory and Techniqu Vol. No.

<P>In this paper, a two-stage broadband CMOS stacked FET RF power amplifier (PA) with a reconfigurable interstage matching network is developed for wideband envelope tracking (ET). The proposed RF PA is designed based on Class-J mode of operation, where the output matching is realized with a two-section low-pass matching network. To overcome the bandwidth (BW) limitation from the high- Q interstage impedance, a reconfigurable matching network is proposed, allowing a triple frequency mode of operation using two RF switches. The proposed RF PA is fabricated in a 0.32- μm silicon-on-insulator CMOS process and shows continuous wave (CW) power-added efficiencies (PAEs) higher than 60% from 0.65 to 1.03 GHz with a peak PAE of 69.2% at 0.85 GHz. The complete ET PA system performance is demonstrated using the envelope amplifier fabricated on the same process. When measured using a 20-MHz BW long-term evolution signal, the overall system PAE of the ET PA is higher than 40% from 0.65 to 0.97 GHz while evolved universal terrestrial radio access adjacent channel leakage ratios are better than -33 dBc across the entire BW after memoryless digital pre-distortion. To our knowledge, this study represents the highest overall system performance in terms of PAE and BW among the published broadband ET PAs, including GaAs HBT and SiGe BiCMOS.</P>

Identifying Affective Factors for Toilet Seat Comfort

Sunghwan Park,Y. L. Rhie,Kyung-Jun Lee,Cherry Ling Yieng Siang,Injae Lee,Myung Hwan Yun 대한인간공학회 2016 대한인간공학회 학술대회논문집 Vol.2016 No.11

The Lifshitz-van der Waals acid-base theory assisted fabrication of MFI-containing mixed matrix membranes for gas separations

Park, Sunghwan,Jang, Eunhee,An, Heseong,Choi, Wansuk,Kim, Jeong-Hoon,Lee, Jung-Hyun,Choi, Jungkyu,Lee, Jong Suk Elsevier 2018 Microporous and mesoporous materials Vol.264 No.-

<P><B>Abstract</B></P> <P>A zeolite-containing mixed matrix membrane (MMM) is an attractive option to overcome the performance limits of polymeric membranes for large-scale gas separations. The poor interfacial adhesion between zeolites and polymers, however, should be addressed to realize the excellent separation performance of zeolites on large industrial scale. Herein, the interfacial void-free MMMs with incorporation of intact MFI type zeolite particles were successfully prepared by applying the Lifshitz-van der Waals acid-base theory for the selection of the appropriate polymer matrix. Our simple, but systematic approach was based on the adhesion force between MFI particles and a surrounding polymer matrix. The relatively high Lewis basicity of cellulose acetate (CA) leads to highest adhesion force with MFI particles among the tested polymer matrices, suppressing interfacial void formation. In addition, a careful analysis revealed that any residual surfactants on the surface of MFI particles are detrimental to fabricate interfacial void-free MMMs. Single gas (i.e. N<SUB>2</SUB> and NF<SUB>3</SUB>) transport in the CA/MFI MMMs were characterized by changing the concentration of MFI particles up to 30 wt%. N<SUB>2</SUB> permeability of CA/MFI MMMs was improved by as much as 304% compared to that of bare CA membranes with maintaining N<SUB>2</SUB>/NF<SUB>3</SUB> permselectivity. Furthermore, gas transports in CA/MFI MMMs by varying the size of MFI particles from 0.2 through 0.6 up to 1.5 <I>μ</I>m were analyzed by using the Lewis-Nielsen model. Our systematic theory-based guidance can be utilized to offer the appropriate polymer candidates for the zeolite-containing MMMs for high performance gas separations.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A simple acid-base theory was systematically applied for ideal MFI-containing MMMs. </LI> <LI> The high carbonyl mole fractions of CA induced a good adhesion between CA and MFI. </LI> <LI> The effect of structure directing agents on the formation of MMMs was investigated. </LI> <LI> Gas transport behaviors in CA/MFI MMMs were analyzed by varying the size of MFI. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Predictors of Permanent Stoma in Mid or Low Rectal Cancer Patients

Sunghwan Kim,Kwang Seop Song,Min-hyun Kim,Sung-Chan Park,Dae Kyung Sohn,Jae Hwan Oh,Ji Won Park,Seung-Yong Jeong,Kyu Joo Park,Heung-Kwon Oh,Duck-Woo Kim,Sung-Bum Kang 대한외과학회 2018 대한외과학회 학술대회 초록집 Vol.2018 No.11

The polymeric upper bound for N₂/NF₃ separation and beyond; ZIF-8 containing mixed matrix membranes

Park, Sunghwan,Kang, Woo Ram,Kwon, Hyuk Taek,Kim, Soobin,Seo, Myungeun,Bang, Joona,Lee, Sang hyup,Jeong, Hae Kwon,Lee, Jong Suk Elsevier 2015 Journal of membrane science Vol.486 No.-

<P><B>Abstract</B></P> <P>Global production for NF<SUB>3</SUB> is continuously increasing, especially due to its heavy consumption in the semiconductor industry. Even though the amount of its emission is relatively small compared to other greenhouse gases, particularly CO<SUB>2</SUB>, the relatively long atmospheric lifetime of NF<SUB>3</SUB> makes its emission cumulative, possibly contributing to the global climate change. Membrane-based separation techniques are very promising for the energy-efficient NF<SUB>3</SUB> recovery. It is, therefore, critically important to evaluate the N<SUB>2</SUB>/NF<SUB>3</SUB> separation performance by using commercial polymeric membranes. Here, for the first time, the empirical N<SUB>2</SUB>/NF<SUB>3</SUB> upper bound relationship is established by using a wide variety of commercial polymeric membranes including both glassy and rubbery polymers based on their single gas (i.e. N<SUB>2</SUB> and NF<SUB>3</SUB>) permeation characterization. Among those tested, 6FDA–DAM:DABA (3:2), Teflon<SUP>®</SUP> AF 2400 and PTMSP exhibited relatively high N<SUB>2</SUB>/NF<SUB>3</SUB> separation performance. The theoretical N<SUB>2</SUB>/NF<SUB>3</SUB> upper bound curve was also defined and found comparable with our empirical upper bound limit. In an effort to improve the N<SUB>2</SUB>/NF<SUB>3</SUB> separation performance, mixed matrix membranes were prepared by incorporating zeolitic imidazolate framework molecular sieves into Matrimid<SUP>®</SUP> 5218. The effects of solvents, particle sizes, and ligands on the transport properties in mixed matrix membranes were investigated.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The empirical N<SUB>2</SUB>/NF<SUB>3</SUB> upper bound was determined by commercial polymeric membranes. </LI> <LI> The theoretical N<SUB>2</SUB>/NF<SUB>3</SUB> upper bound curve was comparable with the empirical one. </LI> <LI> PI/ZIF-8 MMMs improved N<SUB>2</SUB>/NF<SUB>3</SUB> separation performance compared to PI membranes. </LI> <LI> The effect of solvent, particle size, and ligands on transport in MMMs was studied. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

MPCore Based Task Scheduling under Peak Power Constraint

Sunghwan Park,Byunggyu Ahn,Junmo Jung,Hyunglae Roh,Bong-sik Sihn,Liao ZhiRui,Jongwha Chong 대한전자공학회 2007 ITC-CSCC :International Technical Conference on Ci Vol.2007 No.7

In this paper, we propose a new task scheduling algorithm which can chedule tasks under peak power constraint for MPCore systems. To gain accurate power profile of each task, we simulate the tasks under virtual platform which can estimate power consumption of each instruction. And then, we apply PWL (Piece-Wise Linear) modeling to the power profile of each task to divide a task to some sub-tasks. To meet peak power and average power constraints, we schedule each sub-task in MPCore. If there is no dependency between tasks, we use DVS algorithm in each core to minimize power consumption. We demonstrate the proposed approaches using some benchmark applications.

Computational approaches for prediction of protein-protein interaction between Foot-and-mouth disease virus and Sus scrofa based on RNA-Seq

Park, Tamina,Kang, Myung-gyun,Nah, Jinju,Ryoo, Soyoon,Wee, Sunghwan,Baek, Seung-hwa,Ku, Bokkyung,Oh, Yeonsu,Cho, Ho-seong,Park, Daeui The Korean Society of Veterinary Service 2019 韓國家畜衛生學會誌 Vol.42 No.2

Foot-and-Mouth Disease (FMD) is a highly contagious trans-boundary viral disease caused by FMD virus, which causes huge economic losses. FMDV infects cloven hoofed (two-toed) mammals such as cattle, sheep, goats, pigs and various wildlife species. To control the FMDV, it is necessary to understand the life cycle and the pathogenesis of FMDV in host. Especially, the protein-protein interaction between FMDV and host will help to understand the survival cycle of viruses in host cell and establish new therapeutic strategies. However, the computational approach for protein-protein interaction between FMDV and pig hosts have not been applied to studies of the onset mechanism of FMDV. In the present work, we have performed the prediction of the pig's proteins which interact with FMDV based on RNA-Seq data, protein sequence, and structure information. After identifying the virus-host interaction, we looked for meaningful pathways and anticipated changes in the host caused by infection with FMDV. A total of 78 proteins of pig were predicted as interacting with FMDV. The 156 interactions include 94 interactions predicted by sequence-based method and the 62 interactions predicted by structure-based method using domain information. The protein interaction network contained integrin as well as STYK1, VTCN1, IDO1, CDH3, SLA-DQB1, FER, and FGFR2 which were related to the up-regulation of inflammation and the down-regulation of cell adhesion and host defense systems such as macrophage and leukocytes. These results provide clues to the knowledge and mechanism of how FMDV affects the host cell.

Effects of Trunk Stabilization Exercise Using Active Vibration on Spinal Alignment in Normal Adult Females: A Randomized Controlled Trial

Park, Sunghwan,Kim, Yongseong,Park, Chibok International Academy of Physical Therapy Research 2020 Journal of International Academy of Physical Ther Vol.11 No.4

Background: Although studies have been conducted on muscle thickness and balance in trunk stabilization exercise and exercise using vibration props, studies on trunk stabilization exercise using active vibration for spinal alignment are still insufficient to draw a conclusion. Objectives: To investigate the effect of trunk stabilization exercise using active vibration on the spinal alignment in adult females. Design: A randomized controlled trial. Methods: Twenty-six adult females were randomly assigned to the experimental group (active vibration) and 13 control groups (active non-vibrating) and exercised three times a week for 8 weeks. Each group was measured for spinal alignment before exercise and 8 weeks after exercise. Spinal alignment, trunk imbalance, pelvic tilt, and pelvic torsion were measured using a spinal alignment analyzer. Results: Trunk imbalance was a significantly different depending on the time in the experimental group and the control group (P<.05). Pelvic tilt was a significant difference between the groups (P<.05). Also, pelvic tilt was a significantly different depending on the time in the experimental group (P<.05), but the control group showed no significant difference (P>.05). Pelvic torsion was no significant difference in both groups (P>.05). Conclusion: This study demonstrates that trunk stabilization exercise using active vibration has a positive effect on the alignment of the spine.

Rational molecular design of PEOlated ladder-structured polysilsesquioxane membranes for high performance CO₂ removal

Park, Sunghwan,Lee, Albert S.,Do, Yu Seong,Hwang, Seung Sang,Lee, Young Moo,Lee, Jung-Hyun,Lee, Jong Suk The Royal Society of Chemistry 2015 Chemical communications Vol.51 No.83

<P>Poly(methoxy(polyethyleneoxy)propyl-<I>co</I>-methacryloxypropyl) silsesquioxane membranes with different copolymer ratios were successfully fabricated <I>via</I> UV-induced crosslinking with mechanical stability. By selectively introducing polyethylene oxide (PEO) groups covalently bound to the ladder-structured polysilsesquioxane, we effectively suppressed the PEO crystallization, allowing for excellent CO<SUB>2</SUB>/H<SUB>2</SUB> and CO<SUB>2</SUB>/N<SUB>2</SUB> separation under single as well as mixed gas conditions.</P> <P>Graphic Abstract</P><P>By selectively introducing PEO groups into the ladder-structured polysilsesquioxane, PEO crystallization was suppressed, allowing for the exceptional CO<SUB>2</SUB> separation performance. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5cc06269a'> </P>