检索结果-南通市图书馆

Journal of Intelligent Learning Systems and Applications 2014年第2期6卷 125-139页

作者： Asif Rahman Siril Yella mark dougherty Department of Computer Engineering Dalarna UniversityBorlangeSweden Department of Information Technology Orebro UniversityOrebroSweden

Bin planning (arrangements) is a key factor in the timber industry. Improper planning of the storage bins may lead to inefficient transportation of resources, which threaten the overall efficiency and thereby limit the profit margins of sawmills. To address this challenge, a simulation model has been developed. However, as numerous alternatives are available for arranging bins, simulating all possibilities will take an enormous amount of time and it is computationally infeasible. A discrete-event simulation model incorporating meta-heuristic algorithms has therefore been investigated in this study. Preliminary investigations indicate that the results achieved by GA based simulation model are promising and better than the other meta-heuristic algorithm. Further, a sensitivity analysis has been done on the GA based optimal arrangement which contributes to gaining insights and knowledge about the real system that ultimately leads to improved and enhanced efficiency in sawmill yards. It is expected that the results achieved in the work will support timber industries in making optimal decisions with respect to arrangement of storage bins in a sawmill yard.

关键词： Simulation Genetic Algorithm Simulated Annealing Planning and Arrangement Decision Making Storage Bins Log Stackers and Sawmill Yard

Review of the Effectiveness of Vehicle Activated Signs

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Transportation Technologies 2013年第2期3卷 123-130页

作者： Diala Jomaa Siril Yella mark dougherty Department of Computer Engineering Dalarna UniversityBorl?ngeSweden

This paper reviews the effectiveness of vehicle activated signs. Vehicle activated signs are being reportedly used in recent years to display dynamic information to road users on an individual basis in order to give a warning or inform about a specific event. Vehicle activated signs are triggered individually by vehicles when a certain criteria is met. An example of such criteria is to trigger a speed limit sign when the driver exceeds a pre-set threshold speed. The preset threshold is usually set to a constant value which is often equal, or relative, to the speed limit on a particular road segment. This review examines in detail the basis for the configuration of the existing sign types in previous studies and explores the relation between the configuration of the sign and their impact on driver behavior and sign efficiency. Most of previous studies show that these signs have significant impact on driver behavior, traffic safety and traffic efficincy. In most cases the signs deployed have yielded reductions in mean speeds, in speed variation and in longer head-ways. However most experiments reported within the area were performed with the signs set to a certain static configuration within applicable conditions. Since some of the aforementioned factors are dynamic in nature, it is felt that the configurations of these signs were thus not carefully considered by previous researchers and there is no clear statement in the previous studies describing the relationship between the trigger value and its consequences under different conditions. Bearing in mind that different designs of vehicle activated signs can give a different impact under certain conditions of road, traffic and weather conditions the current work suggests that variable speed thresholds should be considered instead.

关键词： Vehicle Activated Signs Variable Message Signs Threshold Trigger Value Speed Variation Traffic Volume Mean Speed

Simulation and Optimization Techniques for Sawmill Yard Operations——A Literature Review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Intelligent Learning Systems and Applications 2014年第1期6卷 21-34页

作者： Asif Rahman Siril Yella mark dougherty Department of Computer Engineering Dalarna UniversityBorlangeSweden Department of Information Technology Orebro UniversityOrebroSweden

Increasing costs and competitive business strategies are pushing sawmill enterprises to make an effort for optimization of their process management. Organizational decisions mainly concentrate on performance and reduction of operational costs in order to maintain profit margins. Although many efforts have been made, effective utilization of resources, optimal planning and maximum productivity in sawmill are still challenging to sawmill industries. Many researchers proposed the simulation models in combination with optimization techniques to address problems of integrated logistics optimization. The combination of simulation and optimization technique identifies the optimal strategy by simulating all complex behaviours of the system under consideration including objectives and constraints. During the past decade, an enormous number of studies were conducted to simulate operational inefficiencies in order to find optimal solutions. This paper gives a review on recent developments and challenges associated with simulation and optimization techniques. It was believed that the review would provide a perfect ground to the authors in pursuing further work in optimizing sawmill yard operations.

关键词： Sawmill Yard Logistics Timber Tucks Log Stackers Simulation and Optimization

Data Based Calibration System for Radar Used by Vehicle Activated Signs

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Data Analysis and Information Processing 2014年第4期2卷 106-116页

作者： Diala Jomaa Siril Yella mark dougherty Karin Edvardsson Department of Computer Engineering Dalarna UniversityBorlangeSweden Department of Construction Technology Dalarna UniversityBorlangeSweden

The accurate measurement of a vehicle’s velocity is an essential feature in adaptive vehicle activated sign systems. Since the velocities of the vehicles are acquired from a continuous wave Doppler radar, the data collection becomes challenging. Data accuracy is sensitive to the calibration of the radar on the road. However, clear methodologies for in-field calibration have not been carefully established. The signs are often installed by subjective judgment which results in measurement errors. This paper develops a calibration method based on mining the data collected and matching individual vehicles travelling between two radars. The data was cleaned and prepared in two ways: cleaning and reconstructing. The results showed that the proposed correction factor derived from the cleaned data corresponded well with the experimental factor done on site. In addition, this proposed factor showed superior performance to the one derived from the reconstructed data.

关键词： Vehicle Activated Signs Doppler Radar Vehicle Velocity Experiment Calibration

Detecting Plants on Railway Embankments

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Software Engineering and Applications 2013年第3期6卷 8-12页

作者： Roger G. Nyberg Narendra Gupta Siril Yella mark dougherty Dalarna University Department of Computer Engineering Borlange Sweden Edinburgh Napier University School of Engineering and the Built Environment Edinburgh UK

This paper investigates problems concerning vegetation along railways and proposes automatic means of detecting ground vegetation. Digital images of railway embankments have been acquired and used for the purpose. The current work mainly proposes two algorithms to be able to achieve automation. Initially a vegetation detection algorithm has been investigated for the purpose of detecting vegetation. Further a rail detection algorithm that is capable of identifying the rails and eventually the valid sampling area has been investigated. Results achieved in the current work report satisfactory (qualitative) detection rates.

关键词： Railway Engineering Railway Embankments Condition Monitoring Image Processing Color Segmentation Railway Maintenance Vegetation Detection

The Public Water Supply Protection Value of Forests: A Watershed-Scale Ecosystem Services Analysis Based upon Total Organic Carbon

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Ecology 2014年第9期4卷 517-531页

作者： Emile Elias David Laband mark dougherty Graeme Lockaby Puneet Srivastava Hugo Rodriguez Biosystems Engineering Auburn University Auburn USA Forestry and Wildlife Science Department Auburn University Auburn USA School of Economics Georgia Institute of Technology Atlanta USA Tetra Tech Inc. Atlanta USA USDA-ARS Jornada Experimental Range New Mexico State University Las Cruces USA

We developed a cost-based methodology to assess the value of forested watersheds to improve water quality in public water supplies. The developed methodology is applicable to other source watersheds to determine ecosystem services for water quality. We assess the value of forest land for source water mitigation of total organic carbon (TOC) through the use of linked watershed and reservoir simulation models and cost-based valuation economics. Watershed modeling results indicated that expected urbanization will increase TOC loads to Converse Reservoir (Mobile, AL). Reservoir model results indicated that future median TOC concentrations increased by 1.1 mg·L-1 between 1992 and 2020 at the source water intake. Depending upon dynamic reservoir TOC concentrations, additional drinking water treatment with powdered activated carbon (PAC) often is necessary between May and October to comply with Safe Drinking Water Act regulations. The cost for additional treatment was calculated using minimum and maximum volume treated with simulated TOC concentrations at the source water intake. Daily simulated TOC concentrations for the base scenario using 1992 land cover (3% urban) were compared with simulated TOC concentrations following forest to urban land conversion predicted in the watershed by 2020 (22% urban). The daily cost for additional drinking water treatment with PAC was calculated if simulated TOC concentrations exceeded 2.7 mg·L-1. The mean increase in daily treatment costs between base and future scenarios ranged from $91 to $95 per km2 per day for forest land water purification ecosystem services.

关键词： Ecosystem Services Water Quality Drinking Water Treatment Urbanization Land Use Change

Cost Effectiveness of Erosion Control Covers during Vegetation Establishment under Simulated Rainfall

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Water Resource and Protection 2015年第2期7卷 119-129页

作者： Ramandeep S. Sidhu mark dougherty Wesley C. Zech Beth Guertal Department of Biosystems Engineering Auburn University Auburn USA Department of Civil Engineering Auburn University Auburn USA Department of Crop Soils and Environmental Sciences Auburn University Auburn USA

The main goal of this study was to quantify reduction of runoff responses using selected erosion control covers on 1.2 m × 0.6 m plots under simulated rainfall to determine the most cost-effective temporary cover treatment under similar soils, rainfall and embankment slope conditions. The different erosion control covers tested were polyacrylamide (PAM), wheat straw and PAM (WS + P) with and without seed;and engineered fiber matrix (EFM) with and without seed. The EFM + S and WS + P + S treatments were the most effective treatments for runoff volume with 68.0% and 48.9% reduction, respectively, as compared to control. EFM + S was the most effective treatment for turbidity and modified total suspended solids (MTSS) with 98.7%, and 99.8% reduction, respectively as compared to control. Vegetation in the wheat straw treatment significantly reduced turbidity but less effect on runoff volume and MTSS than vegetation in the EFM + S treatment. Seeded treatments combined (EFM + S, WS + P + S) had a significant negative correlation between MTSS delivery and time (r = –0.69), as compared to a positive correlation of corresponding non-seeded treatments (EFM, WS + P) over time (r = 0.14). The EFM + S treatment had 39% less average MTSS delivery than WS + P + S but the WS + P + S treatment ($1.03 kg-1 sediment reduction) was found to be 84% less expensive than the EFM + S treatment ($6.36 kg-1 sediment reduction). The WS + P + S treatment can therefore be recommended as the most cost effective method for sediment delivery reduction under similar conditions and within the limitations of this small scale plot study.

关键词： Erosion Sediment Runoff Turbidity Vegetation Water Quality

Multifaceted signaling regulators of chondrogenesis:Implications in cartilage regeneration and tissue engineering

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Genes & Diseases 2015年第4期2卷 307-327页

作者： Jordan D.Green Viktor Tollemar mark dougherty Zhengjian Yan Liangjun Yin Jixing Ye Zachary Collier Maryam K.Mohammed Rex C.Haydon Hue H.Luu Richard Kang Michael J.Lee Sherwin H.Ho Tong-Chuan He Lewis L.Shi Aravind Athiviraham The University of Chicago Pritzker School of Medicine ChicagoIL 60637USA Department of Orthopaedic Surgery and Rehabilitation Medicine The University of Chicago Medical CenterChicagoIL 60637USA Department of Orthopaedic Surgery The Second Affiliated Hospital of Chongqing Medical UniversityChongqing 400016China School of Bioengineering Chongqing UniversityChongqingChina

Defects of articular cartilage present a unique clinical challenge due to its poor self-healing capacity and avascular *** surgical treatment options do not ensure consistent regeneration of hyaline cartilage in favor of fibrous ***,we review the current understanding of the most important biological regulators of chondrogenesis and their interactions,to provide insight into potential applications for cartilage tissue *** include various signaling pathways,including fibroblast growth factors(FGFs),transforming growth factor b(TGF-b)/bone morphogenic proteins(BMPs),Wnt/b-catenin,Hedgehog,Notch,hypoxia,and angiogenic signaling *** and epigenetic regulation of chondrogenesis will also be *** in our understanding of these signaling pathways have led to promising advances in cartilage regeneration and tissue engineering.

关键词： BMPs Cartilage Cell signaling Chondrogenesis FGF Regenerative medicine

Analysis of gateroad stability at two longwall mines based on field monitoring results and numerical model analysis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2019年第1期29卷 35-43页

作者： Gabriel S.Esterhuizen David F.Gearhart Ted Klemetti Heather dougherty mark van Dyke National Institute for Occupational Safety and Health

Coal mine longwall gateroads are subject to changing loading conditions induced by the advancing longwall face. The ground response and support requirements are closely related to the magnitude and orientation of the stress changes, as well as the local geology. This paper presents the monitoring results of gateroad response and support performance at two longwall mines at a 180-m and 600-m depth of *** the first mine, a three-entry gateroad layout was used. The second mine used a four-entry, yieldabutment-yield gateroad pillar system. Local ground deformation and support response were monitored at both sites. The monitoring period started during the development stage and continued during first panel retreat and up to second panel retreat. The two data sets were used to compare the response of the entries in two very different geotechnical settings and different gateroad layouts. The monitoring results were used to validate numerical models that simulate the loading conditions and entry response for these widely differing conditions. The validated models were used to compare the load path and ground response at the two mines. This paper demonstrates the potential for numerical models to assist mine engineers in optimizing longwall layouts and gateroad support systems.

关键词： Coal mining Longwall Gateroad Support Numerical models

Assessing support alternatives for longwall gateroads subject to changing stress

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2021年第1期31卷 103-110页

作者： Gabriel S.Esterhuizen I.Berk Tulu Dave F.Gearhart Heather dougherty mark Van Dyke National Institute for Occupational Safety and Health Pittsburgh Mining Research DivisionPittsburghPA 15236USA West Virginia University MorgantownWV 26506USA

Longwall gateroad entries are subject to changing horizontal and vertical stress induced by redistribution of loads around the extracted *** stress changes can result in significant deformation of the entries that may include roof sag,rib dilation,and floor *** operators install different types of supports to control the ground response and maintain safe access and ventilation of the longwall *** paper describes recent research aimed at quantifying the effect of longwall-induced stress changes on ground stability and using the information to assess support *** research included monitoring of ground and support interaction at several operating longwall mines in the U.S.,analysis and calibration of numerical models that adequately represent the bedded rock mass,and observation of the support systems and their response to changes in *** models were then used to investigate the impact of geology and stress conditions on ground deformation and support response for various depths of cover and geologic *** research results were summarized in two regression equations that can be used to estimate the likely roof deformation and height of roof yield due to longwall-induced stress *** information is then used to assess the ability of support systems to maintain the stability of the *** application of the method is demonstrated with a retrospective analysis of the support performance at an operating longwall mine that experienced a headgate roof *** method is shown to produce realistic estimates of gateroad entry stability and support performance,allowing alternative support systems to be assessed during the design and planning stage of longwall operations.

关键词： Longwall Gateroad Support design Coal Standing support