• Title/Summary/Keyword: trim

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A Study on the Metal Feathered Trim - Focusing on the Excavated Articles from the Old Tombs in Ancient Silla, Gaya - (금속제(金屬製) 조우식(鳥羽飾)에 대(對)한 연구(硏究) - 고신라(古新羅), 가야고분(加耶古墳) 출토품(出土品)을 중심(中心)으로 -)

  • Kim, Moon-Ja
    • Journal of Fashion Business
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    • v.5 no.4
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    • pp.27-36
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    • 2001
  • The purpose of this study is to classify of the Metal Feathered Trim in old tombs. First, Feathered Trim is 5 types, Feathered Trim I-A, Feathered Trim I-B, Feathered Trim II-A, Feathered Trim II-B, Feathered Trim II-C in according to upper part of central insert plate style. Feathered Trim I-A, I-B, II-B type was general style that was found in most of the old tombs in ancient Silla, Gaya. Feathered Trim II-A type was excavated from the only Silla tombs and II-C type was excavated from Gaya tombs. Feathered Trim I-A type was worn previous to I-B type, and II-B, C type was worn previous to II-A type. Feathered Trim 5 types was influenced by the scythe style that was 'Scythe-shaped' tail.

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An Analysis on the Performance of TRIM Commands on SSDs and its Application to the Ext4 File System (SSD에서의 TRIM 명령어 처리 성능 분석 및 Ext4 파일 시스템으로의 적용)

  • Son, Hyobong;Lee, Youngjae;Kim, Yongserk;Kim, Jin-Soo
    • KIISE Transactions on Computing Practices
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    • v.21 no.1
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    • pp.52-57
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    • 2015
  • In this paper, we analyze the performance of the TRIM commands on various SSDs and, based on our analysis results, we enhance the performance of these TRIM commands in the Ext4 file system. We observed that the performance of the TRIM commands improves as the size of the LBA-range increases, the sector number is aligned and continuous or more LBA-ranges are notified via a single TRIM command. However, although the performance is better when multiple LBA-ranges are informed by a single TRIM command, the Ext4 file system issues a single TRIM command for every LBA-range. In this paper, we modify the Ext4 file system to convey at most 64 LBA-ranges per TRIM command. Evaluations through Filebench show that the performance of file deletion operations is improved by up to 35%.

The Analysis of the Ship's Maneuverability According to the Ship's Trim and Draft (선박 TRIM변화에 따른 조종성능의 분석)

  • PARK, Byung-Soo;KANG, Donghoon;KANG, Il-Kwon;KIM, Hyun-Mu
    • Journal of Fisheries and Marine Sciences Education
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    • v.27 no.6
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    • pp.1865-1871
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    • 2015
  • Ship's trim is the one of the most important factor for safety at the sea. Turning circle test and Z-test were carried out to find the effect of ship's trim and draft changes. The results are as follows. 1. If the ship's draft and trim became large, turning circle would be wide. 2. If the ship's draft and trim became large, ship's drift angle would be small. Small drift angle made wide turning circle. 3. Trim by the head made slow ship's final speed when turning circle test. 4. By Z-test, the deeper draft and trim by the stern made small OSA. Small OSA means strong ship's stability. 5. Totally 2nd OSA is smaller than 1st OSA on Z-test. 6. There were small differences of 2nd OSA in trim by the stern, but there were large OSA in trim by the head. 7. The larger trim by the stern, the smaller OSW. The small OSW means better ship's stability and maneuverability.

A Study on the Effect of Trim on the Resistance in a Small Coastwise Passenger Boat (소형연안객선(小型沿岸客船)의 Trim변화(變化)가 저항(抵抗)에 미치는 영향(影響))

  • J.H.,Hwang;K.J.,Bai
    • Bulletin of the Society of Naval Architects of Korea
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    • v.4 no.1
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    • pp.49-54
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    • 1967
  • The authors considered the effects of trim in the small coastal passenger boat upon resistance in this paper. Any change of trim no matter how small, necessarily produces some effect upon resistance. The relations between the resistance coefficients and trim were investigated through the towing test of the Model $MCI-P_1-65$, Korean Standardized Ship, GT 70 tons passenger boat in the gravitational tank. The Lines of the Model are given in Fig. 1. Principal dimensions and other characteristics vary with the trim in general. Those values varied with the trim for $MCI-P_1-65$ are tabulated in table 1. The resistance was measured at five conditions such as even keel, 0.0273L, (original designed trim) 0.0473L, 0.0663L, 0.0873L trim by the stern, fixing the displacement corresponding to the designed load water line. Model was made of wood in length of 3.5 feet coated with varnish, and without appendages. As the artificial turbulent stimulator, the sand strip method was used. The results of model towing tests, correcting to water temperature of $70^{\circ}F$, were expanded to full scale using the Schoenherr's friction formula and surface roughness allowance coefficient of 0.0004. The authors point out, the following results. 1) Optimum trim which gives the minimum resistance exists for every speed at constant displacement and each comes to the same value. For $MCI-P_1-65$ optimum trim is 0.0673L trim by the stern(Fig.4-The cross curves of the resistancecoefficients). 2) At constant displacement, when LCB(longitudinal position of center of buoyancy) varies with the trim, there exists optimum value of LCB which gives minimum resistance for every speed and each comes to the same value. For $MCI-P_1-65$ optimum position of LCB is 8%L aft from midship section (Fig.6).

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Selective Recovery of the SSD TRIM Command in Digital Forensics (디지털 포렌식 관점에서 SSD TRIM 명령의 선별적 복구)

  • Hwang, Hyun Ho;Park, Dong Joo
    • KIPS Transactions on Computer and Communication Systems
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    • v.4 no.9
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    • pp.307-314
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    • 2015
  • Recently, market trends of auxiliary storage device HDD and SSD are interchangeable. In the future, the SSD is expected to be used more popular than HDD as an auxiliary storage device. The TRIM command technique has been proposed and used effectively due to the development of the SSD. The TRIM command techniques can be used to solve the problem of Freezing SSD that operating system cooperates with the SSD. The TRIM command techniques are performed in the idle time of the internal SSD that are actually deleted when a user deletes the data. However, in the point of view of computer forensics, the digital crime is increasing year by year due to lack of data recovery. Thus, this rate of arrest is insufficient. In this paper, I propose a solution that selectively manages data to delete based on advantage of the stability and the write speed of the TRIM command. Through experiments, It is verified by measuring the performance of the traditional method and selected method.

A Study on the Localization of 1500lb High-Pressure Drop Control Valve for Boiler Feedwater Pump (보일러 급수펌프용 1500lb 고차압 제어밸브 국산화 개발에 관한 연구)

  • Lee, Kwon-Il;Jang, Hoon;Lee, Chi-Woo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.21 no.8
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    • pp.19-24
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    • 2022
  • We developed a prototype from the design of a trim, which is the most important in the localization development of a 1500 Ib high-differential pressure-control valve used for boiler feedwater, and measured the flow coefficient, the most basic design data for valves. The following conclusions were drawn. The comparison of the design values of the flow coefficients for the existing X-trim and the multicore trim designed for localization development showed that they were almost identical, and the X-trim value was slightly lower. The comparison of the X-trim and multicore trim based on the valve flow coefficient test showed that they were generally similar, indicating no problem with the design. In the future, we plan to compare and analyze the flow paths for the X-trim and multicore trim via flow analysis.

An Experimental Study on Mean Sinkage and Trim Change in Run, and Form Factor of Full Hull Form (비대선(肥大船)의 항주중(航走中)의 자세변화(姿勢變化)와 형상영향계수(形狀影響係數)에 관(關)하여)

  • Sung-Wan,Hong
    • Bulletin of the Society of Naval Architects of Korea
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    • v.8 no.1
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    • pp.29-40
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    • 1971
  • In order to study the problem on form factor of hull form, towing test of a full ship model was carried out for different initial trims under both full and half load conditions. The results were fully discussed on the mutual relations among initial trim, mean sinkage and trim change in run, and form factor. There exists optimum initial trim in regard to form factor. Mean sinkage and trim change in run can be expressed in a uninominal approximation in the form of $k_i{\cdot}{F_n}^{2.2}$. The coefficients of this approxmation are related linearly with the initial trim. Form factor changes according to Froude number. It is considered that the trim change in run is a main reason of the fact.

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Minimization of Trim Loss Problem in Paper Mill Scheduling Using MINLP (MINLP를 이용한 제지 공정의 파지 손실 최소화)

  • Na, Sung-hoon;Ko, Dae-Ho;Moon, Il
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.392-392
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    • 2000
  • This study performs optimization of paper mill scheduling using MINLP(Mixed-Integer Non-Linear Programming) method and 2-step decomposing strategy. Paper mill process is normally composed of five units: paper machine, coater, rewinder, sheet cutter and roll wrapper/ream wrapper. Various kinds of papers are produced through these units. The bottleneck of this process is how to cut product papers efficiently from raw paper reel and this is called trim loss problem or cutting stock problem. As the trim must be burned or recycled through energy consumption, minimizing quantity of the trim is important. To minimize it, the trim loss problem is mathematically formulated in MINLP form of minimizing cutting patterns and trim as well as satisfying customer's elder. The MINLP form of the problem includes bilinearity causing non-linearity and non-convexity. Bilinearity is eliminated by parameterization of one variable and the MINLP form is decomposed to MILP(Mixed-Integer Linear programming) form. And the MILP problem is optimized by means of the optimization package. Thus trim loss problem is efficiently minimized by this 2-step optimization method.

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A Study of the Shearing Force as a Function Trim Punch Shape and Shearing Angle (트리밍펀치 형상과 전단 각에 따른 전단하중 특성에 관한 연구)

  • Yoo, C.K.;Won, S.T.
    • Transactions of Materials Processing
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    • v.24 no.2
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    • pp.77-82
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    • 2015
  • By investigating the practical use of trim punch configurations for shearing of vehicle panels, the current study first reviews the shearing angle as part of the shearing die design. Based on this review, four different types of trim punch shapes (i.e., horizontal, slope, convex, and concave type) and shearing angles(i.e., 0.76°, 1.53°, 2.29°, 3.05°, 3.81°) were investigated. In order to conduct shearing experiments, four types of trim punch dies were made. The four trim punch dies were tested under various conditions. The experiments used the four trim punch shapes and the five shearing angles. The shearing force varied by shape and decreased from horizontal, slope, convex, to concave for the same shearing angle. The magnitude of shearing force showed differences between the convex and the concave shapes due to the influence of constrained shearing versus free shearing. The test results showed that compared to the horizontal trim punch shearing force, the decrease of the slope, convex, and concave shearing forces were 22.6% to 60.4%. Based on the results, a pad pressure of over 30% is suggested when designing a shearing die.

A High-efficiency Trim Method for CFD Numerical Calculation of Helicopter Rotors

  • Ye, Zhou;Xu, Guo-hua;Shi, Yong-jie;Xia, Run-ze
    • International Journal of Aeronautical and Space Sciences
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    • v.18 no.2
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    • pp.186-196
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    • 2017
  • In order to resolve the trimming difficulty in rotor CFD calculations, a high-efficiency and improved "delta trim method" is established to compute the blade control settings that are necessary to identify the blade motion. In this method, a simplified model which combines the blade element theory and different inflow models is employed to calculate the control settings according to the target aerodynamic forces, then it is coupled into a CFD solver with unsteady Navier-Stokes equations by the delta methodology, which makes the control settings and aerodynamics calculated and updated in the meantime at every trim cycle. Different from the previous work, the current research combines the inflow model based on prescribed wake theory. Using the method established, the control settings and aerodynamic characteristics of Helishape 7A, AH-1G and Caradonna-Tung rotors are calculated. The influence of different inflow models on trimming calculations is analyzed and the computational efficiency of the current "delta trim method" is compared with that of the "CFD-based trim method". Furthermore, for the sake of improving the calculation efficiency, a novel acceleration factor method is introduced to accelerate the trimming process. From the numerical cases, it is demonstrated that the current "delta trim method" has higher computational efficiency than "CFD-based trim method" in both hover and forward flight, and up to 70% of the amount of calculation can be saved by current "delta trim method" which turns out to be satisfactory for engineering applications. In addition, the proposed acceleration factor shows a good ability to accelerate the trim procedure, and the prescribed wake inflow model is always of better stability than other simple inflow models whether the acceleration factor is utilized in trimming calculations.