• Title/Summary/Keyword: Expected reduction

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Robust MILP Model for Scheduling and Design of Multiproduct Batch Processes

  • Suh, Min-ho;Bok, Jin-Kwang;Park, Sunwon;Lee, Tai-yong
    • 제어로봇시스템학회:학술대회논문집
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    • 1998.10a
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    • pp.455-460
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    • 1998
  • We propose robust MILP model for scheduling and design of multiproduct batch processes in this paper. Recent stochastic modeling approaches considering uncertainty have mainly focused on maximization of expected NPV. Robust model concept is applied to generate solution spectrum in which we can select the best solution based on tradeoff between robustness measure and expected NPV. Robustness measure is represented as penalty term in the objective function, which is Upper Partial Mean of NPV. We can quantify solution robustness by this penalty term and maintain model as MILP form to be computationally efficient. An example illustrates the effectiveness of the proposed model. In many cases sufficient robustness can be guaranteed through a little reduction of expected NPV.

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Enhanced Equidistant Chosen Message Power Analysis of RSA-CRT Algorithm (RSA-CRT의 향상된 등간격 선택 평문 전력 분석)

  • Park, Jong-Yeon;Han, Dong-Guk;Yi, Ok-Yeon;Choi, Doo-Ho
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.48 no.2
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    • pp.117-126
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    • 2011
  • RSA-CRT algorithm is widely used to improve the performance of RSA algorithm. However, it is also vulnerable to side channel attacks like as general RSA. One of the power attacks on RSA-CRT, proposed by Boer et al., is a power analysis which utilizes reduction steps of RSA-CRT algorithm with equidistant chosen messages, called as ECMPA(Equidistant Chosen Messages Power Analysis) or MRED(Modular Reduction on Equidistant Data) analysis. This method is to find reduction output value r=xmodp which has the same equidistant patterns as equidistant messages. One can easily compute secret prime p from exposure of r. However, the result of analysis from a reduction step in [5] is remarkably different in our experiment from what Boer expected in [5]. Especially, we found that there are Ghost key patterns depending on the selection of attack bits and selected reduction algorithms. Thus, in this paper we propose several Ghost key patterns unknown to us until now, then we suggest enhanced and detailed analyzing methods.

Evaluation of Advanced Water Treatment Operation

  • Kim, Seung-Hyun
    • Proceedings of the Korean Environmental Health Society Conference
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    • 2002.04a
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    • pp.54-64
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    • 2002
  • This study evaluated advanced water treatment (AWT) system in Korea. There are currently 16 plants operating with AWT. However, no attempt has been made to evaluate AWT system. This study selected one water treatment plant with AWT (pre-ozonation + BAC). Using the operation data from 1995 to 2001 and pilot study results, the post-evaluation of the AWT system has been conducted. The study found that AWT improved water qualities of organic, ammonia, and turbidity, as expected. However, the extent of the improvement was generally short of the pilot study expectations. Pre-ozonation failed to decrease coagulant consumption. The dosage increased rather than decreased. AWT was, however, successful to decrease chlorine consumption. The chlorine reduction was related to the change in raw water characteristics and AWT introduction. Pre-ozonation failed to decrease coagulant consumption. The dosage increased rather than decreased. AWT was, however, successful to decrease chlorine consumption. The chlorine reduction was related to the change in raw water characteristics and AWT introduction, Both operation of pre-ozonation and reduced ammonia loading were responsible for the reduction. AWT increased the operation cost. Maintenance, raw water, and power cost increased, while labor and chemical cost decreased. Manpower reduction resulting form automation caused the decrease of labor cost. The reduction of chlorine consumption caused the decrease of chemical cost.

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High Electrochemical Activity of Pt-Cu Alloy Support on Carbon for Oxygen Reduction Reaction (산소 환원 반응을 위한 탄소기반 Pt-Cu 합금의 높은 전기적 촉매 활성)

  • KIM, HAN SEUL;RYU, SU CHAK;LEE, YOUNG WOOK;SHIN, TAE HO
    • Journal of Hydrogen and New Energy
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    • v.30 no.6
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    • pp.549-555
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    • 2019
  • Electrocatalysis of oxygen reduction reaction (ORR) using Pt nanoparticles or bimetal on carabon was studied. Currently, the best catalyst is platinum, which is a limited resource and expensive to commercialize. In this paper, we investigated the cheaper and more active electrocatalysts by making Pt nanoparticles and adding 3D transition metal such as copper. Electrocatalysts were obtained by chemical reduction based on ethylene glycol solutions. Elemental analysis and particle size were confirmed by XRD and TEM. The electrochemical surface area (ECSA) and activity of the catalyst were determined by electrochemical techniques such as cyclic voltammetry and linear sweep voltammetry method. The commercialized Pt support on carbon (Pt/C, JM), synthesis Pt/C and synthesis Pt3Cu1 alloy nanoparticles supported on carbon were compared. We confirmed that the synthesized Pt3-Cu1/C has high electrochemical performance than commercial Pt/C. It is expected to develop an electrocatalyst with high activity at low price by increasing the oxygen reduction reaction rate of the fuel cell.

A Study on the Greenhouse Gas Emission and Reduction Measures of Domestic Magnesium Production Process (국내 마그네슘 생산공정의 온실가스 배출량 산정 및 감축방안 연구)

  • Kim, Kyung-Nam;Im, Jin-Ah;Yoo, Kyung-Seun
    • Journal of Climate Change Research
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    • v.5 no.3
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    • pp.219-230
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    • 2014
  • In this study, greenhouse gas emission of magnesium industry was estimated and the reduction potential of the greenhouse gas emission was evaluated with reduction technologies. Default value of IPCC guideline was used to calculate the greenhouse gas emission and $SF_6$ alternatives were considered in reduction potential. Import of magnesium ingot was 22,806 ton in 2013, which will be expected to increase to 81,700 ton with 20% rate in 2020. Magnesium ingot was consumed to produce magnesium alloy in diecasting process. Recently, commercial production of crown magnesium and magensium plate began. Based on ingot consumption, $CO_2$ emission of domestic magnesium industry was estimated to 504,000 ton, which is about 0.79% of domestic industrial emissions. Reduction potential of diecasting process was estimated to 489,320 ton by changing SF6 to alternative gases such as HFC-134a, Novec-612. Emission factor of Tier 3 level should be developed to enhance the accuracy of greeenhouse gas emission of magnesium industry.

Study on the Design of Cam-type Transfer Unit (대형 캠 타입 이송장치의 설계에 관한 연구)

  • 이택민;이동윤;양민양
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.1
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    • pp.31-39
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    • 2004
  • This paper presents design solutions for cam type transfer unit in which feeding, lifting, and clamping motions are generated by cams. In order to achieve faster transfer motion, each designed cam must satisfy the given specifications such as velocity, acceleration, jerk, pressure angle, cam thickness, and torque. To reduce absolute torque magnitude and torque variation, a conjugate cam and a torque reduction cam are used respectively. The conjugate cam eliminates the redundant pre-load by using complementary cam to avoid jumping between a cam and a follower. The torque reduction cam reduces the torque variation by applying opposite torque to a cam shaft. The experimental result shows the reductions of the absolute torque value and torque variation. The improvement of working speed and life span of cam type transfer unit can be expected.

Emission Reduction using Unburned Exhaust Gas Ignition (미연배기가스 점화 기술을 이용한 배기저감)

  • 김득상;강봉균;양창석;조용석
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.3
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    • pp.39-47
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    • 2003
  • UEGI (Unburned Exhaust Gas Ignition) is an alternative method for fast light-off of a catalyst. It ignites the unburned exhaust mixture using two glow plugs installed in the upstream of the close-coupled catalysts. In addition, a hydrocarbon adsorber was applied to the UEGI, for more effective reduction of HC emission. Engine bench tests show that the CCC reaches the light-off temperature laster than the baseline exhaust system and HC and CO emissions are reduced significantly during the cold start. From the vehicle test, it was observed that a few amount of HC emission was reduced even the catalysts were aged. It is expected to develop a solution kit applicable to a new vehicle or used one, to meet the emission regulation

Foodborne Pathogen Reduction을 위한 항균제의 새로운 Delivery System인 Aerosolization

  • O, Se-Uk;Gang, Dong-Hyeon
    • Bulletin of Food Technology
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    • v.18 no.1
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    • pp.91-98
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    • 2005
  • Aims: As a preliminary experiment on new sanitizer delivery tools, the efficacy of aerosolizedsanitizer on foodborne pathogens was investigated in larger model chamber system.Methods: Peroxyacetic acid and hydrogen peroxide were aerosolized in a model system againstartificially inoculated target microorganisms on laboratory media. Cultures of 4 different foodborne pathogens were inoculated and affixed onto 3 different heights (bottom, wall, and ceiling), and 3different orientations (face-down, vertical, and face-down) inside a commercial semi-trailer cabinet(14.6 x 2.6 x 2.8 m). Sanitizer was aerosolized into 2 m droplet size fog and treated for 1 h atambient temperature.Results: Populations of Bacillus cereus, Listeria innocua, Staphylococcus aureus, and Salmonellatyphimurium were reduced by an average of 3.09, 7.69, 6.93 and 8.18 log units per plate, respectively.Interestingly, L. innocua, Staph. aureus, and Salm. typhimurium showed statistically not different (P$\leq$ 0.05) reduction patterns relative to height and orientation that were never expected in a sprayingsystemConclusion and significance: Aerosolized sanitizers diffuse like gaseous sanitizers, so it has greatpotential for use in commercial applications.

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Vibration Reduction Effect of the Continuously Welded Rail (장대레일의 진동저감효과에 관한 연구)

  • 황선근;엄기영;고태훈
    • Proceedings of the KSR Conference
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    • 2000.11a
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    • pp.119-125
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    • 2000
  • In this study, field measurements and analysis of vibration before and after the installation of continuously welded rail were performed. The vibration data obtained at the same locations before and after were analyzed to find out the characteristics of vibration level. The component of train-induced impulsive vibration at the rail joints varies depending upon the distance from the source, however mostly low frequency vibration which propagates long distance causes the problems of vibration. Even though it is expected that there may be certain degree of discrepancy in the amount of reduction in vibration depending upon site ground conditions, it was found that installation of continuously welded rail shows reduction in train-induced vibration.

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Alkali-Treatment of Polyester/Cotton Blend Fabric (Polyester/면 혼방직물의 alkali 처리가공)

  • Lee, Suk-Young;Cho, Hwan
    • Textile Coloration and Finishing
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    • v.3 no.3
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    • pp.6-14
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    • 1991
  • To develop an one-bath process for weight-reduction and mercerization of polyester/cotton fabric, concentrated NaOH solution was padded and steam-treated at high temperature. Following results which can be used commercially are obtained. (1) Steaming temperature of 110-12$0^{\circ}C$ is most efficient. (2) Optimum concentration of NaOH solution is 15-20%. (3) Most favorable weight-reduction is 20% in the aspect of fabric handle, and under this treating condition, dye exhaustion onto the mercerized cotton fiber is also increased to 40% or more. From above results, we believe that the economical and concurrent weight-reduction and mercerzation of polyester/cotton fabric can be realized. Moreover, with continuous treatment by pad-steam procedure, it is expected that this is, also, advantageous for the improvement of fabric quality and productivity.

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