• Title/Summary/Keyword: warm in-place

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2R++: Enhancing 2R FTL to Identify Warm Pages (2R++: Warm Page 식별을 통한 2R FTL 개선)

  • Hyojun, An;Sangwon, Lee
    • KIPS Transactions on Computer and Communication Systems
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    • v.11 no.12
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    • pp.419-428
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    • 2022
  • Since in-place updates for pages are not allowed in flash memory, all new page writes should be written in an out-of-place manner. The old overwritten pages are invalidated. Such invalidated pages eventually trigger the costly garbage collection process. Since the garbage collection causes numerous read and write operations, it is one of the flash memory's major performance issues. In 2R, it modified the garbage collection algorithm, which applies the I/O characteristics of the On-Line Transaction Process workload to improve the Write Amplification Factor. However, this algorithm has a region pollution problem. Therefore, in this paper, we developed 2R++ that additionally separates pages with long access intervals to solve the region pollution problem. 2R++ introduces an extra bit per block to separate warm pages based on a second chance mechanism. Prevents warm pages from being misidentified as cold pages to solve region pollution problem. We conducted the experiments on TPC-C and Linkbench to make the performance comparison. The experiment showed that 2R++ achieved a Write Amplification Factor improvement of 57.8% and 13.8% compared to 2R, respectively.

A Fundamental Study for the Efficient Heating System for Warm In-Place Recycling in Korea (국내 현장중온재생공법의 효율적인 가열공정을 위한 기초연구)

  • Kim, Dae-Hun;Kwon, Soo-Ahn;Lee, Jae-Jun
    • International Journal of Highway Engineering
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    • v.18 no.2
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    • pp.29-36
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    • 2016
  • PURPOSES: The objective of this study is to determine the milling temperature that minimizes the binder-induced damage to the aggregate; this is achieved by evaluating the temperature dependence of the viscosity of the asphalt binder, with the aim of developing an effective heating process for warm in-place recycling. METHODS : The validity of the indoor test was confirmed by conducting an internal heating test based on the on-site heating test. In addition, the adhesive power of the binder was measured at various temperatures ($30^{\circ}C$, $40^{\circ}C$, $50^{\circ}C$, $60^{\circ}C$, $70^{\circ}C$) via three types of measuring methods. RESULTS: The surface temperature spectrum of field test was slight different with that of laboratory test. But, the spectra of inner temperature between the field and the laboratory was almost similar. Also, the adhesion of the asphalt binder was measured from $30^{\circ}C$ to $70^{\circ}C$. The adhesion of the binder was significantly decreased from $60^{\circ}C$. Contrary to other temperature, the adhesion was slightly changed from $60^{\circ}C$ to $70^{\circ}C$. Also the inner temperature between two different heating methods was shown similar temperature spectra. CONCLUSIONS: The pavement heating temperature spectrum of hot in place recycling method was simulated by a laboratory test. Based on this study, the optimum temperature was $60^{\circ}C{\sim}70^{\circ}C$ for reducing aggregate damage during milling process. The susceptibility heating method developed in this study can be maintained the optimum inner temperature range.

Effect of Initial Texture on the Evolution of Warm Rolling Texture and Microstructure in Aluminum Alloy Sheet (알루미늄 판재의 온간압연 집합조직과 미세조직에 미치는 초기 집합조직의 영향)

  • Kim H. D.;Huh M. Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2001.10a
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    • pp.138-141
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    • 2001
  • The evolution of lectures and microstructure during the warm-rolling and subsequent annealing in aluminum 3004 alloy sheets was investigated by employing X-ray texture measurements and microstructure observations. Whereas the typical $\beta$-fiber orientations with the strong Bs-orientation $\{112\}<110>$ formed in the normally cold-rolled specimen, the warm-rolling at $250^{\circ}C$ led to the development of a strong through thickness texture gradient which was characterized by shear texture at the surface layer and rolling textures at the center layer After warm rolling, ultra-fine grains formed in the thickness layer with shear texture components. Upon recrystallization annealing, the $\{001\}<100>$ Cube-texture developed at the expense of normal rolling texture components the rise to the formation of corase recrystallized grains. However, in the layer with shear texture components the continuous recrystallization took place and the fine grain size persisted even after recrystallization annealing.

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A Study on Constitutive Equations for Warm and Hot Forging (온, 열간 단조의 구성방정식에 관한 연구)

  • 강종훈;박인우;제진수;강성수
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.9
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    • pp.75-81
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    • 1998
  • Simulations of warm and hot forming processes need reliable expressions of flow stress at high temperatures. To get flow stress of the materials usually tension, compression and torsion tests are conducted. In this study, hot compression tests were adopted to get flow stress of medium carbon steel. Experiments have been conducted under both isothermal, near constant strain rate in the temperature ranges 650~100$0^{\circ}C$. Phase transformation takes place by temperature changes for steels in hot and warm forging stage. So Constitutive equation are formulated as the function of strain, strain rate and temperature for isothermal conditions and phase transformation.

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Fundamental Study for Development of Pre-Heater for Warm In-Place Recycling in Korea (국내 현장중온재생공법의 프리히터 개발을 위한 기초연구)

  • Kim, Dae-Hun;Kim, Seung-Hoon;Kwon, Soo-Ahn;Kim, Yongjoo;Lee, Jaejun
    • International Journal of Highway Engineering
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    • v.17 no.2
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    • pp.31-37
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    • 2015
  • PURPOSES : To design a pre-heater for warm in-place recycling equipment, three different heating systems were evaluated to determine their thermal efficiency. METHODS: In this study, a $30cm{\times}30cm{\times}15cm$ wheel-tracking specimen was used to measure the inner temperature as a function of the heating system. The inner temperature of the specimen was measured with a data logger at the surface, and at depths of 1cm, 2cm, 3cm, 4cm, and 5cm. To evaluate the thermal efficiency, the researchers used three different types of equipment, namely, IR, a heating wire, and a gas burner. RESULTS: The IR heating system exhibits a higher level of performance than the others to achieve the target temperature at a depth of 5cm in the specimen. The gas burner system was capable of heating the surface to a temperature of up to $600^{\circ}C$. The other types, however, cannot heat the surface up to 600. The thermal efficiencies were measured based on the laboratory conditions. CONCLUSIONS: To find the most effective system for application to the development of a pre-heater for warm in-place recycling, various systems (IR, heating wire, gas burner) were examined in the laboratory. As a result, it was found that the hot plate of a gas burner system provides the highest temperature at the surface of the asphalt but, of all the systems, the IR system provides the best internal temperature increase rate. Furthermore, a gas burner can age the asphalt binder of the surface layer as a result of the high temperature. However, the gas burner cannot attain the target temperature at 5cm. The IR system, on the other hand, is effective at increasing the internal temperature of asphalt.

Formation of Shear Texture and Microstructure in AA3004 Sheet (AA3004에서 전단변형 미세조직 및 집합조직의 형성)

  • 이강노;김종국;김훈동;황병복;허무영
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2002.05a
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    • pp.184-186
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    • 2002
  • The evolution of texture and microstructure during warm rolling and subsequent annealing in aluminium 3004 alloy sheet was investigated by X-ray texture measurements and microstructure observations. Warm rolling at 250$^{\circ}C$ led to the development of strong through thickness texture gradients with shear textures at the surface layer and a regular rolling texture in the center of the sheets. FEM simulations indicated that these texture gradients are caused by pronounced strain gradients throughout the sheet thickness. Upon recrystallization annealing, in the sheet center the characteristic cube-recrystallization texture developed, while in the surface layers with a pronounced shear texture continuous recrystallization took place which led to the formation of a very fine grained microstructure. It is concluded that the very complex strain history in the near-surface layers together with the resulting high work-hardening rate gave rise to the formation of the ultra-fine grains with an average size smaller than 2$\mu\textrm{m}$.

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Deformation Behavior of $CU_{54}Ni_6Zr_{22}Ti_{18}$ Bulk Amorphous Alloy during Multi-Pass Warm Rolling (동계 벌크 아몰퍼스의 다단 온간 압연시 변형 거동)

  • Park E. S.;Kim H. J.;Bae J. C.;Huh M. Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.10a
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    • pp.139-142
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    • 2005
  • Cu-Ni-Zr-Ti bulk amorphous thin strips were produced by multi-pass warm rolling of the amorphous powder at temperatures in the supercooled liquid region. Process variables for rolling of the bulk amorphous strips were properly controlled to prevent onset of crystallization and failure during rolling up to three passes. During rolling of the amorphous powder, both the deformation and densification took place and the newly developed surface on the deformed amorphous particles enhances the consolidation leading to an increase in the strength. The strain state during rolling was analyzed by FEM.

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Fluctuation Characteristic of Temperature and Salinity in Coastal Waters around Jeju Island (제주도 연안 천해역의 수온 · 염분 변동 특성)

  • KO Jun-Cheol;KIM Jun-Teck;KIM Sang-Hyun;RHO Hong-Kil
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.36 no.3
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    • pp.306-316
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    • 2003
  • We conducted a time-series analysis of temperature and salinity of sea water around Jeju Island, Korea. Monthly mean temperature and salinity was influenced by precipitation and weather conditions on Jeju as well as by oceanographic conditions of the open sea such as the Tsushima Warm Current and sea water in coastal areas. Salinity of Jeju coastal waters was the highest in April, and it was always over 34.00 psu with tiny fluctuation between December and June. Due to the effects of the Tsushima Warm Current, Jeju coastal waters maintained high salinity and stability. Low salinity and its large fluctuations during summer were closely associated with the China Coastal Water and precipitation in Jeju. The place of the lowest water temperature was the northeast coasts of Jeju (Gimneong, Hado, Jongdalri). In winter, as warmer water of the Tsushima Warm Current appeared in western area of Jeju dwindled flowing along the northern coasts of Jeju area and becoming cool, the lowest water temperature often appeared locally in Gimnyeong and its vicinitly in summer. The Tsushima Warm Current flows into the east entrance of Jeju Strait, but its influence is weak because of geometry and strong vertical mixing due to fast tidal currents.

A Fundamental Study of Rejuvenator for Warm in Place Recycling Asphalt Pavement Mixtures (현장 중온 재생 혼합물용 재생첨가제의 기초적인 연구)

  • Park, JaeYoung;Lee, Kanghun;Kwon, SooAhn;Lee, JaeJun
    • International Journal of Highway Engineering
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    • v.19 no.5
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    • pp.13-20
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    • 2017
  • PURPOSES : This research was a laboratory study for evaluating the Reclaimed Asphalt Pavement (RAP) mixture added developed rejuvenator for warm mix recycling. Waste asphalt mixtures occupy about 18.2% of construction wastes in Korea. Moreover, most rejuvenators were imported from Europe or the U.S. Therefore, improving usage of RAP with a developed rejuvenator material provides environmental protection at a reduced cost. METHODS : The specimen used for this experiment was performed by only using RAP. A suitable rejuvenator for Target PG was then added. In addition, a conventional rejuvenator was selected to compare performance and specimens introduced with the same procedure as the developed rejuvenator was prepared. In order to evaluate rutting resistance and water susceptibility, we conducted a deformation strength test, a tensile strength ratio test, and a dynamic immersion test with the prepared mixtures. RESULTS :Laboratory test results indicated that both the developed additive and conventional additive improved performance of the recycled asphalt mixtures compared to mixtures without the rejuvenator. In addition, the deformation strength test and TSR test results satisfied standards for domestic recycling asphalt mixtures. The dynamic immersion test showed that the developed rejuvenator has superior scaling resistance than the conventional rejuvenator. CONCLUSIONS : In terms of rutting resistance and moisture susceptibility, the warm mix recycled asphalt mixtures with the developed rejuvenator appeared to effectively recovered performance.

On the Warm Eddies in the Southwestern Part of the East Sea (the Japan Sea) (동해 남서해역에서의 난수성 소용돌이에 대하여)

  • AN, HUISOO;SHIM, KYUNGSIN;SHIN, HONG-RYEOL
    • 한국해양학회지
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    • v.29 no.2
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    • pp.152-163
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    • 1994
  • The characteristics and fluctuations of structures and spatial distributions of warm eddies (anticyclonic eddies) in the southwestern part of the East Sea (the Japan Sea) are discussed based on the data gathered y the Fisheries Research and Development Agency, Korea from 1967 to 1968. The warm eddies existed very often in the southwest of the Ullung Island. The warm eddies are elliptical in shape and the mean size is about 130 km in diameter. Bimonthly distributions of warm eddies, the largest value of observed frequency and diameter in August and the least in June, indicate that the generation of the warm eddy is related with the development of the East Korean Warm Current. The warm eddies move west, north or southward with 0.80∼2.50 cm/sec or stay over a few months at the same place southwest of the Ullung Island. Movement of warm eddies may be influenced by the neighboring currents, the Rossby wave and the topography. The relationship between the position of warm eddies and the bottom topography suggests that the development and the movement of warm eddies are controlled by the Ullung Basin. The warm eddies should be divided into two groups. One group is the shallow warm eddy with strong baroclinic characteristics and the other is the deep one with strong Barotropic characteristics. The shallow group seems to be closely related with positive values (in summer) of the sea level difference between Pusan and Mozi (the Tsushima Current), while the deep group has no relation with that.

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