• Title/Summary/Keyword: stochastic conditions

Search Result 294, Processing Time 0.027 seconds

Semi-domesticated and Irreplaceable Genetic Resource Gayal (Bos frontalis) Needs Effective Genetic Conservation in Bangladesh: A Review

  • Uzzaman, Md. Rasel;Bhuiyan, Md. Shamsul Alam;Edea, Zewdu;Kim, Kwan-Suk
    • Asian-Australasian Journal of Animal Sciences
    • /
    • v.27 no.9
    • /
    • pp.1368-1372
    • /
    • 2014
  • Several studies arduously reported that gayal (Bos frontalis) is an independent bovine species. The population size is shrinking across its distribution. In Bangladesh, it is the only wild relative of domestic cattle and also a less cared animal. Their body size is much bigger than Bangladeshi native cattle and has prominent beef type characters along with the ability to adjust in any adverse environmental conditions. Human interactions and manipulation of biodiversity is affecting the habitats of gayals in recent decades. Besides, the only artificial reproduction center for gayals, Bangladesh Livestock Research Institute (BLRI), has few animals and could not carry out its long term conservation scheme due to a lack of an objective based scientific mission as well as financial support. This indicates that the current population is much more susceptible to stochastic events which might be natural catastrophes, environmental changes or mutations. Further reduction of the population size will sharply reduce genetic diversity. In our recent investigation with 80K indicine single nucleotide polymorphism chip, the $F_{IS}$ (within-population inbreeding) value was reported as $0.061{\pm}0.229$ and the observed ($0.153{\pm}0.139$) and expected ($0.148{\pm}0.143$) heterozygosities indicated a highly inbred and less diverse gayal population in Bangladesh. Prompt action is needed to tape the genetic information of this semi-domesticated bovine species with considerable sample size and try to investigate its potentials together with native zebu cattle for understanding the large phenotypic variations, improvement and conservation of this valuable creature.

A Study on an Efficient Double-fleet Operation of the Korean High Speed Rail (한국 고속철도의 효율적 중련편성 운영방법에 대한 연구)

  • Oh, Seog-Moon;Sohn, Moo-Sung;Choi, In-Chan
    • Journal of the Korean Society for Railway
    • /
    • v.10 no.6
    • /
    • pp.742-750
    • /
    • 2007
  • This paper presents a mathematical model for a double-fleet operation in Korean high speed rail (HSR). KORAIL has a plan to launch new HSR units in 2010, which are composed of 10 railcars. The double-fleet operation assigns a single-unit or two-unit fleet to a segment, accommodating demand fluctuation. The proposed model assumes stochastic demand and uses chance-constrained constraints to assure a preset service level. It can be used in the tactical planning stage of the rail management as it includes several real-world conditions, such as the capacities of the infra-structures and operational procedures. In the solution approach, the expected revenue in the objective function is linearized by using expected marginal revenue, and the chance-constrained constraints are linearized by assuming that demands are normally distributed. Subsequently, the model can be solved by a mixed-integer linear programming solver fur small size problems. The test results of the model applied to Friday morning train schedules for one month sample data from KTX operation in 2004 shows that the proposed model could be utilized to determine the effectiveness of double-fleet operation, which could significantly increase the expected profit and seat utilization rates when properly maneuvered.

VOQL : A Visual Object Query Language (Stochastic VOQL : 시각적 객체 질의어)

  • Kim, Jeong-Hee;Cho, Wan-Sup;Lee, Suk-Kyoon;Whang, Kyung-Young
    • Journal of the Institute of Electronics Engineers of Korea CI
    • /
    • v.38 no.5
    • /
    • pp.1-15
    • /
    • 2001
  • Expressing complex query conditions in a concise and intuitive way has been a challenge in the design of visual object-oriented query languages. We propose a visual query language called VOQL (Visual Object oriented Query Language) for object oriented databases. By employing the visual notation of graph and Venn diagram, the database schema and the advanced features of object oriented queries such as multi-valued path expressions and quantifiers can be represented in a simple way. VOQL has such good features as simple and intuitive syntax, well-defined semantics, and excellent expressive power of object-oriented queries compared with previous visual object-oriented query languages.

  • PDF

Prediction of Carbonation Progress for Concrete Structures Considering Change of Atmospheric Environment (대기환경변화를 고려한 콘크리트 구조물의 중성화 예측)

  • Lee, Chang-Soo;Yoon, In-Seok
    • Journal of the Korea Concrete Institute
    • /
    • v.15 no.4
    • /
    • pp.574-584
    • /
    • 2003
  • The most common deterioration cause of concrete structures in urban environment is carbonation. Recently, the $CO_2$ concentration and temperature at atmosphere is sharply increased with time due to global warming phenomena. In this study, the climate scenario IS92a, which was suggested by the IPCC, is used to consider temperature and atmospheric $CO_2$ concentration change in the model of service life prediction. The modified mathematical solution, which was based on the Fick's 1st law of diffusion, was used to reflect concrete materials properties such as the degree of hydration of concrete with elapsed time, and important parameters, which associated with deterioration rate. The techniques of service life prediction are developed introducing the method of reliability and stochastic concept to consider microclimatic condition in Seoul, South Korea. From the result of service life prediction, concrete containing high W/C ratio is shown fast carbonation rate due to $CO_2$ concentration increase. It is concluded that the deterioration of concrete structures due to carbonation is insignificant problem on the conditions that below W/C 55%, well curing concrete.

Ambient vibration testing of Berta Highway Bridge with post-tension tendons

  • Kudu, Fatma Nur;Bayraktar, Alemdar;Bakir, Pelin Gundes;Turker, Temel;Altunisik, Ahmet Can
    • Steel and Composite Structures
    • /
    • v.16 no.1
    • /
    • pp.21-44
    • /
    • 2014
  • The aim of this study is to determine the dynamic characteristics of long reinforced concrete highway bridges with post-tension tendons using analytical and experimental methods. It is known that the deck length and height of bridges are affected the dynamic characteristics considerably. For this purpose, Berta Bridge constructed in deep valley, in Artvin, Turkey, is selected as an application. The Bridge has two piers with height of 109.245 m and 85.193 m, and the total length of deck is 340.0 m. Analytical and experimental studies are carried out on Berta Bridge which was built in accordance with the balanced cantilever method. Finite Element Method (FEM) and Operational Modal Analysis (OMA) which considers ambient vibration data were used in analytical and experimental studies, respectively. Finite element model of the bridge is created by using SAP2000 program to obtain analytical dynamic characteristics such as the natural frequencies and mode shapes. The ambient vibration tests are performed using Operational Modal Analysis under wind and human loads. Enhanced Frequency Domain Decomposition (EFDD) and Stochastic Subspace Identification (SSI) methods are used to obtain experimental dynamic characteristics like natural frequencies, mode shapes and damping ratios. At the end of the study, analytical and experimental dynamic characteristic are compared with each other and the finite element model of the bridge was updated considering the material properties and boundary conditions. It is emphasized that Operational Modal Analysis method based on the ambient vibrations can be used safely to determine the dynamic characteristics, to update the finite element models, and to monitor the structural health of long reinforced concrete highway bridges constructed with the balanced cantilever method.

A Study on the Determination of Water Storage-Supply Capacity of Agricultural Reservoir (소규모 농업용 저수지의 저류량-용수공급능력 결정에 관한 연구)

  • 안승섭;정순돌;이증석;윤경덕;장인수
    • Journal of Environmental Science International
    • /
    • v.11 no.12
    • /
    • pp.1217-1226
    • /
    • 2002
  • This study aims at the effective estimation of water supply capacity of small scale reservoir and the proposal of the data which is necessary to establish the water resources management plan of down stream area of the reservoir in the future by comparison and examination about reservoir operation technique for the security of agricultural water in small scale reservoir. The result of flow calculation by Tank model is used for the input data as the inflow data which is needed for the analysis of water supply capacity. Stochastic method, simulation method, and optimization method are used to examine the water supply capacity, and water security amount is compared with each method. From the analyses of water supply capacities by each method, slightly different results are shown in spite of the effort to compare them equally using input data such as inflow data under equal conditions, and the comparison of water supply capacities by each method are as follows; linear planning method, simulation method, and transition probability matrix method in the order of amount from the largest. It is thought that the simulation method in which comparatively reasonable application of the inflow data is possible and is simulated in successive time series dam operation of the three methods used in this study thus, simulation model is proper to estimate the water supply capacity of agricultural small scale reservoir. And it is judged that the heightening of efficiency of water resources utilization according to the development of downstream area of dam may be possible using the upward readjusted water supply amount of $55.18{\tiems}10^6ton$ and $63.7{\times}10^6ton$ at 95% and 90% supply reliability respectively which are above the planning water supply amount of $50.0{\times}10^6$ton when the simulation method is introduced as the standard.

Cash flow Forecasting in International Construction Projects through Categorized Risk Analysis (특성별 리스크 분석을 통한 해외건설공사 현금흐름 예측에 관한 연구)

  • Yeom, Sang-Min;Han, Seung-Heon;Kim, Du-Yeon;Nam, Ha-Na;Park, Hee-Dae
    • Proceedings of the Korean Institute Of Construction Engineering and Management
    • /
    • 2006.11a
    • /
    • pp.295-300
    • /
    • 2006
  • In this research, risk factors which can raise project cost are identified in the initial stage and picked out through the decision maker's baseline. And also this probable risks are implemented to the project cash flow to estimate the contingency and to build a risk management system in the level of project. The risks that affect the projects profits were classified in two categories in the risk checklist. Firstly, financial risks derived from the external economic conditions for example exchange rate, escalation, interest rates etc. are analyzed through the stochastic methods, Monte-Carlo Simulation. Secondly, the project individual risks which are come from the project characteristics, for example country risk, clime, owner etc., are evaluated using the utility curve of the decision maker. Finally these risk analysis methods are used to forecast the actual project cash flow and final profit.

  • PDF

Simulation Model of Dual-Species Biofilm Growth in Hydrodynamic Flow (유체 흐름 안에서 두 종의 생물막 성장 시뮬레이션 모델)

  • Jeon, Won-Ju;Lee, Sang-Hee
    • Journal of the Korea Society for Simulation
    • /
    • v.20 no.1
    • /
    • pp.97-105
    • /
    • 2011
  • In rivers and streams, biofilms are thin layers of greenish-brown slime attached to rocks, plants, and other surfaces. Biofilms play key roles in primary production and cycling of nutrients, water quality remediation, suspended sediment removal, and energy flow to higher trophic levels. In the present study, we developed a two-dimensional cellular automata model to simulate mixed biofilms of toxin-sensitive and toxin-producing species in hydrodynamic flow. The flow was generated by a stochastic process for uniform flow and by using the Navier-Stokes equation for non-uniform flow. Minimized local rules governing reproduction and mortality of the species were executed in the self-organizing processes to elucidate interactions between toxin-producing and toxin-sensitive species in competition over nutrients. We briefly discuss the morphology of the simulated biofilm under different flow conditions.

Chaotic Analysis of Water Balance Equation (물수지 방정식의 카오스적 분석)

  • 이재수
    • Water for future
    • /
    • v.27 no.3
    • /
    • pp.45-54
    • /
    • 1994
  • Basic theory of fractal dimension is introduced and performed for the generated time series using the water balance model. The water balance equation over a large area is analyzed at seasonal time scales. In the generation and modification of mesoscale circulation local recycling of precipitation and dynamic effects of soil moisture are explicitly included. Time delay is incorporated in the analysis. Depending on the parameter values, the system showed different senarios in the evolution such as fixed point, limit cycle, and chaotic types of behavior. The stochastic behavior of the generated time series is due to deterministic chaos which arises from a nonlinear dynamic system with a limited number of equations whose trajectories are highly sensitive to initial conditions. The presence of noise arose from the characterization of the incoming precipitation, destroys the organized structure of the attractor. The existence of the attractor although noise is present is very important to the short-term prediction of the evolution. The implications of this nonlinear dynamics are important for the interpretation and modeling of hydrologic records and phenomena.

  • PDF

Quantitative evaluation of radar reflectivity and rainfall intensity relationship parameters uncertainty using Bayesian inference technique (Bayesian 추론기법을 활용한 레이더 반사도-강우강도 관계식 매개변수의 불확실성 정량적 평가)

  • Kim, Tae-Jeong;Park, Moon-Hyeong;Kwon, Hyun-Han
    • Journal of Korea Water Resources Association
    • /
    • v.51 no.9
    • /
    • pp.813-826
    • /
    • 2018
  • Recently, weather radar system has been widely used for effectively monitoring near real-time weather conditions. The radar rainfall estimates are generally relies on the Z-R equation that is an indirect approximation of the empirical relationship. In this regards, the bias in the radar rainfall estimates can be affected by spatial-temporal variations in the radar profile. This study evaluates the uncertainty of the Z-R relationship while considering the rainfall types in the process of estimating the parameters of the Z-R equation in the context of stochastic approach. The radar rainfall estimates based on the Bayesian inference technique appears to be effective in terms of reduction in bias for a given season. The derived Z-R equation using Bayesian model enables us to better represent the hydrological process in the rainfall-runoff model and provide a more reliable forecast.