• Title/Summary/Keyword: Initial Design Step

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Web Program for Laboratory Animal Group Separation Based on Biological Characteristics (생체지표를 활용한 웹기반의 실험동물 군(郡) 분리 프로그램)

  • Kim, Chang-Hwan;Lee, Dae-Sang
    • KSBB Journal
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    • v.27 no.1
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    • pp.40-44
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    • 2012
  • The laboratory animal group separation is dividing animal population into subgroups, which have similar average and standard deviation values among the subgroups, based on the biological characteristics such as body weight, glucose level in blood, etc. Although group separation is very important and initial step in experimental design, it needs a labor intensive process for researchers because of making similar average and standard deviation values among the subgroups using the raw biological characteristics. To reduce the labor cost and increase the efficiency of animal grouping, we developed a web program named as laboratory animal group separation (LAGS) program. This LAGS uses biological characteristics of population, number of group, and the number of elements per each subgroup as input data. The LAGS automatically separates the population into each subgroup that has similar statistical data such as average and standard deviation values among subgroups. It also provides researchers with the extraordinary data generated in the process of grouping and the final grouping results by graphical display. Through our LAGS, researchers can validate and confirm results of laboratory animal group separation by just a few mouse clicks.

A Wideband Clock Generator Design using Improved Automatic Frequency Calibration Circuit (개선된 자동 주파수 보정회로를 이용한 광대역 클록 발생기 설계)

  • Jeong, Sang-Hun;Yoo, Nam-Hee;Cho, Seong-Ik
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.2
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    • pp.451-454
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    • 2011
  • In this paper, a wideband clock generator using novel Automatic frequency calibration(AFC) scheme is proposed. Wideband clock generator using AFC has the advantage of small VCO gain and wide frequency band. The conventional AFC compares whether the feedback frequency is faster or slower then the reference frequency. However, the proposed AFC can detect frequency difference between reference frequency with feedback frequency. So it can be reduced an operation time than conventional methods AFC. Conventional AFC goes to the initial code if the frequency step changed. This AFC, on the other hand, can a prior state code so it can approach a fast operation. In simulation results, the proposed clock generator is designed for DisplayPort using the CMOS ring-VCO. The VCO tuning range is 350MHz, and a VCO frequency is 270MHz. The lock time of clock generator is less then 3us at input reference frequency, 67.5MHz. The phase noise is -109dBC/Hz at 1MHz offset from the center frequency. and power consumption is 10.1mW at 1.8V supply and layout area is $0.384mm^2$.

Nonsteady Plane-strain Ideal Forming with Elastic Dead Zone (탄성 변형 영역을 고려한 비정상 평면 변형 이상 공정 이론)

  • Lee W.;Chung K.;Alexandrov S.;Kang T.J.
    • Transactions of Materials Processing
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    • v.13 no.6 s.70
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    • pp.540-545
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    • 2004
  • Ever since the ideal forming theory has been developed for process design purposes, application has been limited to sheet forming and, fur bulk forming, to two-dimensional steady flow. Here, application for the non-steady case was performed under the plane-strain condition based on the theory previously developed. In the ideal flow, material elements deform following the minimum plastic work path (or mostly proportional true strain path) so that the ideal plane-stram flow can be effectively described using the two-dimensional orthogonal convective coordinate system. Besides kinematics, fur a prescribed final part shape, schemes to optimize a preform shape out of a class of initial configurations and also to define the evolution of shapes and boundary tractions were developed. Discussions include the two problematic issues on internal tractions and the non-monotonous straining. For demonstration purposes, numerical calculations were made for a bulk part under forging.

Control Performance Evaluation of MR Brake Depending on Durability (MR 브레이크의 내구성에 따른 제어성능평가)

  • Kim, Wan Ho;Park, Jhin Ha;Yang, Soon Yong;Shin, Cheol Soo;Choi, Seung-Bok
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.26 no.6_spc
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    • pp.660-666
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    • 2016
  • This paper presents performance comparison results of magneto-rheological (MR) brake in the sense of wear characteristics. To create wear circumstance, the brake is operated in 100 000 cycles by DC motor. To make wear test in same design parameters such as the radius of the housing, ferromagnetic disc and gap size, small sample of stainless are inserted in housing of MR brake. The performances of brake are compared between the initial stage (no wear) and 100 000 revolution cycles operated stage (wear). At each circumstance, torque of the brake is measured and compared by applying step current and sinusoidal control input. The controller used in this work is a simple, but effective PID controller. It is demonstrated that the wear behavior is more obvious as the operating cycle is increased in the torque control process.

A simplified framework for estimation of deformation pattern in deep excavations

  • Abdollah Tabaroei;Reza Jamshidi Chenari
    • Geomechanics and Engineering
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    • v.37 no.1
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    • pp.31-48
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    • 2024
  • To stabilize the excavations in urban area, soil anchorage is among the very common methods in geotechnical engineering. A more efficient deformation analysis can potentially lead to cost-effective and safer designs. To this end, a total of 116 three-dimensional (3D) finite element (FE) models of a deep excavation supported by tie-back wall system were analyzed in this study. An initial validation was conducted through examination of the results against the Texas A&M excavation cases. After the validation step, an extensive parametric study was carried out to cover significant design parameters of tie-back wall system in deep excavations. The numerical results indicated that the maximum horizontal displacement values of the wall (δhm) and maximum surface settlement (δvm) increase by an increase in the value of ground anchors inclination relative to the horizon. Additionally, a change in the wall embedment depth was found to be contributing more to δvm than to δhm. Based on the 3D FE analysis results, two simple equations are proposed to estimate excavation deformations for different scenarios in which the geometric configuration parameters are taken into account. The model proposed in this study can help the engineers to have a better understanding of the behavior of such systems.

A Study on Optimal Placement of Underwater Target Position Tracking System considering Marine Environment (해양환경을 고려한 수중기동표적 위치추적체계 최적배치에 관한 연구)

  • Taehyeong Kim;Seongyong Kim;Minsu Han;Kyungjun Song
    • Journal of the Korea Institute of Military Science and Technology
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    • v.26 no.5
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    • pp.400-408
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    • 2023
  • The tracking accuracy of buoy-based LBL(Long Base Line) systems can be significantly influenced by sea environmental conditions. Particularly, the position of buoys that may have drifted due to sea currents. Therefore it is necessary to predict and optimize the drifted-buoy positions in the deploying step. This research introduces a free-drift simulation model using ocean data from the European CMEMS. The simulation model's predictions are validated by comparing them to actual sea buoy drift tracks, showing a substantial match in averaged drift speed and direction. Using this drift model, we optimize the initial buoy layout and compare the tracking performance between the center hexagonal layout and close track layout. Our results verify that the optimized layout achieves lower tracking errors compared to the other two layout.

Studies on Vegetation for Ecological Restoration of Salt Marshes in Saemangeum Reclaimed Land - Population Formation Strategies of Halophytes - (새만금 간척지일대 염습지 생태복원을 위한 식생학적 연구 -염생식물의 개체군 형성 전략-)

  • Kim, Chang-Hwan
    • Journal of Environmental Science International
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    • v.18 no.4
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    • pp.463-471
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    • 2009
  • A study on vegetation in the Mangyeong River and Dongjin River basins and the surrounding regions of the Saemangeum Reclaimed Land was conducted in a series of efforts to determine the expected ecological changes in the salt marshes, to restore their vegetation, to explore the restoring force of halophyte, to examine the community mechanism and, ultimately, to rehabilitate marshy land vegetation along the lakeside, coastal dune and salt marshes of the Saemangeum Project Area. The findings of the study may be summed up as follows: Five species such as Suaeda japonica, Salicornia herbacea, Atriplex gmelini, Aster tripolium and Suaeda asparagoides that are mostly distributed in the estuary of the Saemangeum Reclaimed Land were analyzed to examine the mechanism of halophyte to maintain their community. To find out the strategies of plants for survival and the cause of forming community structure, a research was made as for appearance ratio of biomass, root lengths and germination. With regard to biomasses of halophyte, the biomass of Suaeda japonica increases rapidly, while Salicornia herbacea adopts a strategy of unstable growth pattern by which the biomass increases slowly in parallel with its slow speed of growth since initial appearance of young sapling. In contrast, Suaeda asparagoides, Atriplex gmelini and Aster tripolium choose to adapt themselves to environment promptly by being transformed into life form of annual or biennial plant, a pattern that is presumed to be favorable and stable for survival in the later stage of growth. In short, there is a sharp distinction among the 5 species: i.e. Suaeda japonica that begins to grow fast in the length of surface and underground section but slows down from the mid-stage on; Salicornia herbacea that grows slowly in the beginning step but starts to step up from the middle onward; Atriplex gmelini and Aster tripolium growing slowly in the initial stage but fast later on; and Suaeda asparagoides that turns from the constant growth in the beginning to rapid growth in the later period. The outcomes of the analysis into status of growth and influencing factors of Suaeda japonica in the sowing field that is most widely prevalent in the Saemangeum Reclaimed Land as a sort of ecological pioneer in the salt marshes showed that the average size of grass lands, density and number of individuals increase in the natural sowing field as well as in the plowing field regardless of their physical as well as physico-chemical features of the soil as the season progresses from June to October of a year.

A Study on Analysis Method to Evaluate Influence of Damage on Composite Layer in Type3 Composite Cylinder (Type3 복합재료 압력용기의 복합재층 손상에 따른 영향성 평가를 위한 해석기법에 관한 연구)

  • Lee, Kyo-Min;Park, Ji-Sang;Lee, Hak-Gu;Kim, Yeong-Seop
    • Composites Research
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    • v.23 no.6
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    • pp.7-13
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    • 2010
  • Type3 cylinder is a composite pressure vessel fully over-wrapped with carbon/epoxy composite layers over an aluminum liner, which is the most ideal and safe high pressure gas container for CNG vehicles due to the lightweight and the leakage-before-burst characteristics. During service in CNG vehicle, if a fiber cut damage occurs in outer composite layers, it can degrade structural performance, reducing cycling life from the original design life. In this study, finite element modeling and analysis technique for the composite cylinder with fiber-cut crack damage is presented. Because FE analysis of type3 cylinder is path dependant due to plastic deformation of aluminum liner in autofrettage process, method to introduce a crack into FE model affect analysis result. A crack should be introduced after autofrettage in analysis step considering real circumstances where crack occurs during usage in service. For realistic simulation of this situation, FE modeling and analysis technique introducing a crack in the middle of analysis step is presented and the results are compared with usual FE analysis which has initial crack in the model from the beginning of analysis. Proposed analysis technique can be used effectively in the evaluation of influence of damage on composite layers of type3 cylinder and establish inspection criteria of composite cylinder in service.

Evaluation of Prestress Loss in Prestressing Reinforcing Units using Steel Bar and Pipe (강봉 및 강관을 이용한 프리스트레싱 유닛의 긴장 응력 손실 평가)

  • Sim, Jae-Il;Mun, Ju-Hyun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.25 no.4
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    • pp.75-82
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    • 2021
  • The objective of this study is to examine the loss of prestressing stress in the developed prestressing reinforcing units using steel bar and pipe (SP). The main parameters were the reinforcing bar type, the magnitude of prestressed force, and prestressing method. The test results showed that the loss of prestressing stress for SP was highest in the initial prestressing step, which was higher for the compression introduction typed specimens than tension introduction typed specimens. The loss of prestressing stress of SP made with P800 was 1.6% for the compression introduction typed specimen with 0.8fy, which was lowest than the other specimens. Meanwhile, the relaxation of SP with the respect to the time ranged between 0.4 and 1.9%, irrespective of SP material type, the magnitude of prestressed force, and prestressing method. These values were less than 2.5%, which is the maximum value for the relaxation of prestressed reinforcing steel bars in design codes. Consequently, considering the loss of stress developed in the initial prestressing step, the developed SP material type, prestressing introduction method, and magnitude are recommended to be P800, compression introduction type, and 0.8fy.

A Comparative Analysis of Cognitive Thinking Process for Character Design Between Korea and China (한국과 중국의 캐릭터 디자인과정 인지적 사고특성 비교분석)

  • Zhang, Xiao Bo;Kim, KieSu
    • The Journal of the Korea Contents Association
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    • v.17 no.9
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    • pp.672-680
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    • 2017
  • Today the distribution of characters in the consumer market based on digital smart phones is expanding, and the characters themselves are sold with independent merchandise, also various application researches about character are being activated. However, depending on the style of worker 's work on the design process of Korea and China regarding characters, there are differences in design characteristics and the diversity of work. In this study, we attempted to investigate the implications of these designers on the development of creative character design through in-depth research and experiment. Therefore, previous researches of cognitive science were investigated and cognitive experiments were conducted on design process for experts. For this research experiment, the initial sketch stage in the character work of Korea and China was recorded by the method of the designer by the subject through the protocol analysis method which is the qualitative research method. We coded the collected language based on this recording experiment and analyzed the problem behavior. We examined how the cognitive acts are done by the designer to develop the characters. The behavior characteristics and the accidental characteristics. The differences of the behavioral characteristics and the accidental characteristics in each step of the character design process were identified. Through these cognitive experiments, we could examine the behavior analysis of the design thinking process in Korea and China. In the field of design practice, we can set the direction of the design work process of the two countries and help us to produce creative and individual results. I think. These studies are expected to contribute to practical application of product marketing and new cooperation development methods in terms of activation of character industry in the future.