The common reflection surface (CRS) stack is based on the local dip of the reflector and the reflection response within the first Fresnel zone. During the CRS stack all the information given by a multi-coverage refl...The common reflection surface (CRS) stack is based on the local dip of the reflector and the reflection response within the first Fresnel zone. During the CRS stack all the information given by a multi-coverage reflection dataset can be successfully utilized. By now, it is known as the best zero-offset (ZO) imaging method. In this paper high quality CRS kinematic parameter sections are obtained by a modified CRS optimization strategy. Then stack apertures are calculated using the parameter sections which finally results in the realization of the CRS stack based on optimized aperture. Thus the advantages of CRS parameters are fully developed. Application to model and real seismic data reveals that, compared with the image section by a conventional CRS stack, the image section by CRS stack based on an optimized aperture improves both the signal-to-noise ratio and the continuity of reflection events.展开更多
[ Objective] The aim of this study was to provide a theoretical basis for population and application of Chinese herbal feed additive in the rex rabbit breeding. [ Methyl] 108 weaned -rex rabbits aged 40 days were divi...[ Objective] The aim of this study was to provide a theoretical basis for population and application of Chinese herbal feed additive in the rex rabbit breeding. [ Methyl] 108 weaned -rex rabbits aged 40 days were divided into three groups with thirty -six each group. Group A were fed basal diet, while group B were fed basal diet supplemented with 0.3% Chinese herbal feed additive and group C were fed basal diet supplemented with 0.4% Chinese herbal feed additive. The meat quality indexes were measured when feeding to 150 age in days. [ Result] There was significant difference among pH value, water loss rate, storing loss rate and crude protein content in each group (P〈0.05), but no significant difference was found in tenderness, cooking percentage, moisture content and crude fat content ( P 〉 0.05). The total content of ami- no acids, essential amino acids and semi essential amino acids as well as main delicious amino acids was highest in group C accounting for 23.84%, 11.47% and 8.32% respectively, next came group B accounting for 20.94%, 10.64% and 6.81% respectively, and lowest in group C ( control group) accounting for 19.06%, 9.61% and 6.46% respectively. [ Conclusion] The Chinese herbal feed additive can improve meat quality of rex rabbit the best addition of 0.4%.展开更多
A series of dynamic model tests that were performed on a geogrid-reinforced square footing are presented.The dynamic(sinusoidal)loading was applied using a mechanical testing and simulation(MTS)electro-hydraulic servo...A series of dynamic model tests that were performed on a geogrid-reinforced square footing are presented.The dynamic(sinusoidal)loading was applied using a mechanical testing and simulation(MTS)electro-hydraulic servo loading system.In all the tests,the amplitude of loading was±160 kPa;the frequency of loading was 2 Hz.To better ascertain the effect of reinforcement,an unreinforced square footing was first tested.This was followed by a series of tests,each with a single layer of reinforcement.The reinforcement was placed at depths of 0.3B,0.6B and 0.9B,where B is the width of footing.The optimal depth of reinforcement was found to be 0.6B.The effect of adopting this value versus the other two depths was quantified.The single layer of geogrid had an effective reinforcement depth of 1.7B below the footing base.The increase of the depth between the topmost geogrid layer and the bottom of the footing(within the range of 0.9B)did not change the failure mode of the foundation.展开更多
A series of investigations were conducted to study the bearing capacity and load transfer mechanism of stiffened deep cement mixed (SDCM) pile. Laboratory tests including six specimens were conducted to investigate ...A series of investigations were conducted to study the bearing capacity and load transfer mechanism of stiffened deep cement mixed (SDCM) pile. Laboratory tests including six specimens were conducted to investigate the frictional resistance between the concrete core and the cementsoil. Two model piles and twenty-four full-scale piles were tested to examine the bearing behavior of single pile. Laboratory and model tests results indicate that the cohesive strength is large enough to ensure the interaction between core pile and the outer cement-soil. The full-scale test results show that the SDCM piles exhibit similar bearing behavior to bored and cast-in-place concrete piles. In general, with the rational composite structure the SDCM piles can transmit the applied load effectively, and due to the addition of the stiffer core, the SDCM piles possess high bearing capacity. Based on the findings of these experimental investigations and theoretical analysi , a practical design method is developed to predict the vertical bearing capacity of SDCM pile.展开更多
A weighted time-based global hierarchical path planning method is proposed to obtain the global optimal path from the starting point to the destination with time optimal control. First, the grid-or graph-based modelin...A weighted time-based global hierarchical path planning method is proposed to obtain the global optimal path from the starting point to the destination with time optimal control. First, the grid-or graph-based modeling is performed and the environment is divided into a set of grids or nodes. Then two time-based features of time interval and time cost are presented. The time intervals for each grid are built, during each interval the condition of the grid remains stable, and a time cost of passing through the grid is defined and assigned to each interval. Furthermore, the weight is introduced for taking both time and distance into consideration, and thus a sequence of multiscale paths with total time cost can be achieved. Experimental results show that the proposed method can handle the complex dynamic environment, obtain the global time optimal path and has the potential to be applied to the autonomous robot navigation and traffic environment.展开更多
In order to improve the seismic performance of Chinese traditional stele relics, a suitable aseismic strengthening method of Chinese traditional stele relics is proposed. Taking the typical stele relic in Xi'an Beili...In order to improve the seismic performance of Chinese traditional stele relics, a suitable aseismic strengthening method of Chinese traditional stele relics is proposed. Taking the typical stele relic in Xi'an Beilin as an example, the on-site investigations were carried out to obtain the actual geometric size and damage state of the stele relic. Then, the structural performance of the stele relic was analyzed by the finite element software ANSYS. Finally, the two different aseismic strengthening methods of the traditional stele relic are proposed and comparatively analyzed. The results show that in addition to the common problems, such as weathering, and cracks, etc, earthquakes seriously threaten the structural safety of stele relics. Under the rarely-occurring earthquake of eight degree, the unstrengthened stele relic will be overturned, and many cracks will occur at the connection area of stele body and stele pedestal. When the stele relic is strengthened by the stainless angle steel strengthening method, the stele relic will not be overturned, but some cracks will occur at the connection area of stele body and stele pedestal. When the stele relic is strengthened by the base isolation strengthening method, the stele relic will not be overturned, and no cracks will occur at the connection area of stele body and stele pedestal. Therefore, the aseismic strengthening effect of the base isolation strengthening method is obviously better than that of the stainless angle steel strengthening method, and this method is a suitable aseismic strengthening method of Chinese traditional stele relics.展开更多
A novel weighted evolving network model based on the clique overlapping growth was proposed.The model shows different network characteristics under two different selection mechanisms that are preferential selection an...A novel weighted evolving network model based on the clique overlapping growth was proposed.The model shows different network characteristics under two different selection mechanisms that are preferential selection and random selection.On the basis of mean-field theory,this model under the two different selection mechanisms was analyzed.The analytic equations of distributions of the number of cliques that a vertex joins and the vertex strength of the model were given.It is proved that both distributions follow the scale-free power-law distribution in preferential selection mechanism and the exponential distribution in random selection mechanism,respectively.The analytic expressions of exponents of corresponding distributions were obtained.The agreement between the simulations and analytical results indicates the validity of the theoretical analysis.Finally,three real transport bus networks(BTNs) of Beijing,Shanghai and Hangzhou in China were studied.By analyzing their network properties,it is discovered that these real BTNs belong to a kind of weighted evolving network model with clique overlapping growth and random selection mechanism that was proposed in this context.展开更多
This study investigated the preference for wood and plastic-based ceiling panels by homeowners in Ghana, the implications for the conservation of tropical forests and prospects for the local wood processing industry. ...This study investigated the preference for wood and plastic-based ceiling panels by homeowners in Ghana, the implications for the conservation of tropical forests and prospects for the local wood processing industry. Questionnaire was used to solicit information from 758 homeowners sampled from three cities in Ghana. The results showed that even though wood-based panels continue to enjoy strong patronage among home owners plastic-based panels appear to be the future material for ceiling. The findings suggest that, by 2030, homeowners in Ghana will use more plastic-based ceiling panels than wood-based panels, ceteris paribus. Attractiveness, durability and pleasantness are the key attributes of plastics that influence homeowners' decision to patronize the material. Additionally, the concern about the depletion of forest resources in Ghana has shaped homeowners decision to patronize plastic-based ceiling panels. While the shift to the use of plastic-based panels has the potential to moderate the consumption levels of timber and therefore could contribute to the conservation of tropical forests, it has a negative implication on the development of local wood processing industry. One area where manufacturers of wood products such as wood panels can explore in order to increase or maintain the market share of wood-based panel products is sourcing raw timber from certified forests.展开更多
Public Key Encryption with Keyword Search (PEKS), an indispensable part of searchable encryption, is stock-in- trade for both protecting data and providing operability of encrypted data. So far most of PEKS schemes ...Public Key Encryption with Keyword Search (PEKS), an indispensable part of searchable encryption, is stock-in- trade for both protecting data and providing operability of encrypted data. So far most of PEKS schemes have been established on Identity-Based Cryptography (IBC) with key escrow problem inherently. Such problem severely restricts the promotion of IBC-based Public Key Infrastructure including PEKS component. Hence, Certificateless Public Key Cryptography (CLPKC) is efficient to remove such problem. CLPKC is introduced into PEKS, and a general model of Certificateless PEKS (CLPEKS) is formalized. In addition, a practical CLPEKS scheme is constructed with security and efficiency analyses. The proposal is secure channel free, and semantically secure against adaptive chosen keyword attack and keyword guessing attack. To illustrate the superiority, massive experiments are conducted on Enron Email dataset which is famous in information retrieval field. Compared with existed constructions, CLPEKS improves the efficiency in theory and removes the key escrow problem.展开更多
A dynamic cooperation model of multi-agent is established by combining reinforcement learning with distributed artificial intelligence(DAI),in which the concept of individual optimization loses its meaning because of ...A dynamic cooperation model of multi-agent is established by combining reinforcement learning with distributed artificial intelligence(DAI),in which the concept of individual optimization loses its meaning because of the dependence of repayment on each agent itself and the choice of other agents.Utilizing the idea of DAI,the intellectual unit of each robot and the change of task and environment,each agent can make decisions independently and finish various complicated tasks by communication and reciprocation between each other.The method is superior to other reinforcement learning methods commonly used in the multi-agent system.It can improve the convergence velocity of reinforcement learning,decrease requirements of computer memory,and enhance the capability of computing and logical ratiocinating for agent.The result of a simulated robot soccer match proves that the proposed cooperative strategy is valid.展开更多
The paper deals on a significant retrofit project currently under construction of an existing hospital building in Avellino (Italy). The seismic retrofit was realized by connecting together the first floors of the t...The paper deals on a significant retrofit project currently under construction of an existing hospital building in Avellino (Italy). The seismic retrofit was realized by connecting together the first floors of the three existing structures and by creating a unique isolation system composed of high damping rubber bearings and sliding devices. The base isolation is achieved by gradually cutting the building from foundation and installing the isolators at the level of upper edge of the columns. The study allows the verification of the adequacy of the isolation system, showing the benefits of the application of the isolation devices, the limitations and the characteristics of their performance.展开更多
The corrective machining to compensate the resulting errors is usually tried at plural times based on the trial-and-error process when the machining is realized in die and mold manufacturing. This corrective machining...The corrective machining to compensate the resulting errors is usually tried at plural times based on the trial-and-error process when the machining is realized in die and mold manufacturing. This corrective machining has an influence on accuracy and efficiency and is an important factor. The measurement system for measuring the forms of die and mold at all times is essential in order to machine the die and mold with high accuracy and efficiency. However, the problems of management and operation errors are found in compensating process of die and mold machining. In this paper, an online machining and measurement system in die and mold manufacturing is developed in order to overcome these problems. In this online system, 2-axis control system is added to a surface roughness measuring instrument, and both NC machining program and measured data are linked and controlled using a same computer. Therefore, the machining and measurement can be recognized for consistent process, and can be realized on the machine. This system has the advantages such as the high accuracy, low-price, and online convenience and so on. The possibility of practical use of this online system was investigated by fundamental experiments.展开更多
Different driving decisions will cause different processes of phase transition in traffic flow. To reveal the inner mechanism, this paper built a new cellular automaton (CA) model, based on the driving decision (DD...Different driving decisions will cause different processes of phase transition in traffic flow. To reveal the inner mechanism, this paper built a new cellular automaton (CA) model, based on the driving decision (DD). In the DD model, a driver's decision is divided into three stages: decision-making, action, and result. The acceleration is taken as a decision variable and three core factors, i.e. distance between adjacent vehicles, their own velocity, and the preceding vehicle's velocity, are considered. Simulation results show that the DD model can simulate the synchronized flow effectively and describe the phase transition in traffic flow well. Further analyses illustrate that various density will cause the phase transition and the random probability will impact the process. Compared with the traditional NaSch model, the DD model considered the preceding vehicle's velocity, the deceleration limitation, and a safe distance, so it can depict closer to the driver preferences on pursuing safety, stability and fuel-saving and has strong theoretical innovation for future studies.展开更多
Two practical crawlspace heating systems introduced in detached houses have been chosen as a field study. One is the crawlspace warm air heating system and the other is the crawlspace hot water circulation system. Bas...Two practical crawlspace heating systems introduced in detached houses have been chosen as a field study. One is the crawlspace warm air heating system and the other is the crawlspace hot water circulation system. Based on the field study result, by using the simulation sol, ware, THERB, the effectiveness of the crawlspace warm air heating system has been examined. The effect of the factors, such as the wind amount circulating between crawlspace and indoor space, foundation insulation condition, and heat amount into the crawlspace, on the indoor thermal environment has been analyzed. Based on these analyses, the measured crawlspace heating system can make the average temperature of the living room above 20℃. These two houses have excellent thermal environment. According to the simulating result, heat amount input into crawlspace, which can make comfortable indoor thermal environment, for every month in heating period has been roughly concluded, and they are 600 W in December and March and 800 W in February and January, respectively.展开更多
Repeatedly unidirectional bending(RUB) was applied to the magnesium alloy sheet to improve the basal texture.The effect of RUB temperature on resulting structure and room temperature properties was investigated.The te...Repeatedly unidirectional bending(RUB) was applied to the magnesium alloy sheet to improve the basal texture.The effect of RUB temperature on resulting structure and room temperature properties was investigated.The texture components of the sheet undergoing RUB at recovery temperature were similar to those of the sheet undergoing RUB at room temperature(RT).As the RUB temperature increased to above recrystallization temperature,the texture components became more disperse and the pyramidal components increased.With the increase of RUB temperature,the grain size near the surface of the sheets undergoing RUB tended to grow up.When the sheets were processed by RUB at medium-high temperature followed by annealing at 533 K,the yield strength and fracture elongation were lower than those of the cold rolled sheet;however,the Erichsen value was slightly higher than that of the cold rolled sheet.The sheet undergoing RUB at RT followed by annealing at 533 K represented the best mechanical properties.展开更多
A unity transformation model (UTM) was presented for flexible NC machining of spiral bevel gears and hypoid gears. The model can support various machining methods for Gleason spiral bevel gears and hypoid gears, inclu...A unity transformation model (UTM) was presented for flexible NC machining of spiral bevel gears and hypoid gears. The model can support various machining methods for Gleason spiral bevel gears and hypoid gears, including generation machining and formation machining for wheel or pinion on a universal five-axis machining center, and then directly produce NC codes for the selected machining method. Wheel machining and pinion machining under UTM were simulated in Vericut 6.0 and tested on a five-axis machining center TDNC-W2000 with NC unit TDNC-H8. The results from simulation and real-cut verify the feasibility of gear machining under UTM as well as the correctness of NC codes.展开更多
Cloud computing can offer a very powerful, reliable, predictable and scalable computing infrastructure for the execution of MAS (multi-agent systems) implementing complex agent-based applications such when modelling...Cloud computing can offer a very powerful, reliable, predictable and scalable computing infrastructure for the execution of MAS (multi-agent systems) implementing complex agent-based applications such when modelling, simulation and real-time running of complex systems must be provided. Multi-agent systems appears as an adequate approach to current challenges in many areas. Between important qualities of MAS also belongs to, that they are open, interoperable, and heterogenous systems. The agent is active, a program entity, has its own ideas how to perform the tasks of the own agenda. Agents: perceive, behave "reasonably", act in the environment, communicate with other agents. Cloud infrastructures can offer an ideal platform where run MAS systems simulations, applications and real-time running because of its large amount of processing and memory resources that can be dynamically configured for executing large agent-based software at unprecedented scale. Cloud computing can help chemical and food companies drive operational excellence; meet growing and changing customer demands; accelerate new product innovation and ramp-to-volume manufacturing in key markets; reduce IT spending; manage and mitigate supply chain risks; and enable faster and more flexible delivery of new IT system. Production type of SOC (service-oriented computing) can be inspired by a "Cloud", for the production of "Cloud" offers an attractive and natural solutions in several computing trends such as delivery system over the Internet, use of utilities, flexibility, virtualization, a "grid" distributed computing, outsourcing, Web 2.0, etc.. Production of the "Cloud" is also considered as a new multidisciplinary field that includes "network" production, virtual manufacturing, agile manufacturing, and of course cloud computing. Examples of cloud computing and MAS applications in food and chemistry development and industry, proposition of using multi-agent systems in the control of batch processes, modified ACO (ant colony optimization) approach for the diversified service allocation and scheduling mechanism in cloud paradigma, examples of applications in a business area were studied in the paper.展开更多
基金sponsored by the 863 Program (Grant No.2006AA06Z206)the 973 Program (Grant No.2007CB209605)
文摘The common reflection surface (CRS) stack is based on the local dip of the reflector and the reflection response within the first Fresnel zone. During the CRS stack all the information given by a multi-coverage reflection dataset can be successfully utilized. By now, it is known as the best zero-offset (ZO) imaging method. In this paper high quality CRS kinematic parameter sections are obtained by a modified CRS optimization strategy. Then stack apertures are calculated using the parameter sections which finally results in the realization of the CRS stack based on optimized aperture. Thus the advantages of CRS parameters are fully developed. Application to model and real seismic data reveals that, compared with the image section by a conventional CRS stack, the image section by CRS stack based on an optimized aperture improves both the signal-to-noise ratio and the continuity of reflection events.
文摘[ Objective] The aim of this study was to provide a theoretical basis for population and application of Chinese herbal feed additive in the rex rabbit breeding. [ Methyl] 108 weaned -rex rabbits aged 40 days were divided into three groups with thirty -six each group. Group A were fed basal diet, while group B were fed basal diet supplemented with 0.3% Chinese herbal feed additive and group C were fed basal diet supplemented with 0.4% Chinese herbal feed additive. The meat quality indexes were measured when feeding to 150 age in days. [ Result] There was significant difference among pH value, water loss rate, storing loss rate and crude protein content in each group (P〈0.05), but no significant difference was found in tenderness, cooking percentage, moisture content and crude fat content ( P 〉 0.05). The total content of ami- no acids, essential amino acids and semi essential amino acids as well as main delicious amino acids was highest in group C accounting for 23.84%, 11.47% and 8.32% respectively, next came group B accounting for 20.94%, 10.64% and 6.81% respectively, and lowest in group C ( control group) accounting for 19.06%, 9.61% and 6.46% respectively. [ Conclusion] The Chinese herbal feed additive can improve meat quality of rex rabbit the best addition of 0.4%.
基金Projects(41962017,51469005)supported by the National Natural Science Foundation of ChinaProject(2017GXNSFAA198170)supported by the Natural Science Foundation in Guangxi Province,China+1 种基金Project supported by the Guangxi University of Science and Technology Innovation Team Support Plan,ChinaProject supported by the High Level Innovation Team and Outstanding Scholars Program of Guangxi Institutions of Higher Learning,China。
文摘A series of dynamic model tests that were performed on a geogrid-reinforced square footing are presented.The dynamic(sinusoidal)loading was applied using a mechanical testing and simulation(MTS)electro-hydraulic servo loading system.In all the tests,the amplitude of loading was±160 kPa;the frequency of loading was 2 Hz.To better ascertain the effect of reinforcement,an unreinforced square footing was first tested.This was followed by a series of tests,each with a single layer of reinforcement.The reinforcement was placed at depths of 0.3B,0.6B and 0.9B,where B is the width of footing.The optimal depth of reinforcement was found to be 0.6B.The effect of adopting this value versus the other two depths was quantified.The single layer of geogrid had an effective reinforcement depth of 1.7B below the footing base.The increase of the depth between the topmost geogrid layer and the bottom of the footing(within the range of 0.9B)did not change the failure mode of the foundation.
文摘A series of investigations were conducted to study the bearing capacity and load transfer mechanism of stiffened deep cement mixed (SDCM) pile. Laboratory tests including six specimens were conducted to investigate the frictional resistance between the concrete core and the cementsoil. Two model piles and twenty-four full-scale piles were tested to examine the bearing behavior of single pile. Laboratory and model tests results indicate that the cohesive strength is large enough to ensure the interaction between core pile and the outer cement-soil. The full-scale test results show that the SDCM piles exhibit similar bearing behavior to bored and cast-in-place concrete piles. In general, with the rational composite structure the SDCM piles can transmit the applied load effectively, and due to the addition of the stiffer core, the SDCM piles possess high bearing capacity. Based on the findings of these experimental investigations and theoretical analysi , a practical design method is developed to predict the vertical bearing capacity of SDCM pile.
基金Supported by the National Natural Science Foundation of China(No.61100143,No.61370128)the Program for New Century Excellent Talents in University of the Ministry of Education of China(NCET-13-0659)Beijing Higher Education Young Elite Teacher Project(YETP0583)
文摘A weighted time-based global hierarchical path planning method is proposed to obtain the global optimal path from the starting point to the destination with time optimal control. First, the grid-or graph-based modeling is performed and the environment is divided into a set of grids or nodes. Then two time-based features of time interval and time cost are presented. The time intervals for each grid are built, during each interval the condition of the grid remains stable, and a time cost of passing through the grid is defined and assigned to each interval. Furthermore, the weight is introduced for taking both time and distance into consideration, and thus a sequence of multiscale paths with total time cost can be achieved. Experimental results show that the proposed method can handle the complex dynamic environment, obtain the global time optimal path and has the potential to be applied to the autonomous robot navigation and traffic environment.
基金The National Natural Science Foundation of China(No.51578127,51778122)the Foundation for the Author of National Excellent Doctoral Dissertation of China(No.201452)the Fundamental Research Funds for the Central Universities(No.2242016K41065)
文摘In order to improve the seismic performance of Chinese traditional stele relics, a suitable aseismic strengthening method of Chinese traditional stele relics is proposed. Taking the typical stele relic in Xi'an Beilin as an example, the on-site investigations were carried out to obtain the actual geometric size and damage state of the stele relic. Then, the structural performance of the stele relic was analyzed by the finite element software ANSYS. Finally, the two different aseismic strengthening methods of the traditional stele relic are proposed and comparatively analyzed. The results show that in addition to the common problems, such as weathering, and cracks, etc, earthquakes seriously threaten the structural safety of stele relics. Under the rarely-occurring earthquake of eight degree, the unstrengthened stele relic will be overturned, and many cracks will occur at the connection area of stele body and stele pedestal. When the stele relic is strengthened by the stainless angle steel strengthening method, the stele relic will not be overturned, but some cracks will occur at the connection area of stele body and stele pedestal. When the stele relic is strengthened by the base isolation strengthening method, the stele relic will not be overturned, and no cracks will occur at the connection area of stele body and stele pedestal. Therefore, the aseismic strengthening effect of the base isolation strengthening method is obviously better than that of the stainless angle steel strengthening method, and this method is a suitable aseismic strengthening method of Chinese traditional stele relics.
基金Projects(60874080,60504027) supported by the National Natural Science Foundation of ChinaProject(20060401037) supported by the National Postdoctor Science Foundation of China
文摘A novel weighted evolving network model based on the clique overlapping growth was proposed.The model shows different network characteristics under two different selection mechanisms that are preferential selection and random selection.On the basis of mean-field theory,this model under the two different selection mechanisms was analyzed.The analytic equations of distributions of the number of cliques that a vertex joins and the vertex strength of the model were given.It is proved that both distributions follow the scale-free power-law distribution in preferential selection mechanism and the exponential distribution in random selection mechanism,respectively.The analytic expressions of exponents of corresponding distributions were obtained.The agreement between the simulations and analytical results indicates the validity of the theoretical analysis.Finally,three real transport bus networks(BTNs) of Beijing,Shanghai and Hangzhou in China were studied.By analyzing their network properties,it is discovered that these real BTNs belong to a kind of weighted evolving network model with clique overlapping growth and random selection mechanism that was proposed in this context.
文摘This study investigated the preference for wood and plastic-based ceiling panels by homeowners in Ghana, the implications for the conservation of tropical forests and prospects for the local wood processing industry. Questionnaire was used to solicit information from 758 homeowners sampled from three cities in Ghana. The results showed that even though wood-based panels continue to enjoy strong patronage among home owners plastic-based panels appear to be the future material for ceiling. The findings suggest that, by 2030, homeowners in Ghana will use more plastic-based ceiling panels than wood-based panels, ceteris paribus. Attractiveness, durability and pleasantness are the key attributes of plastics that influence homeowners' decision to patronize the material. Additionally, the concern about the depletion of forest resources in Ghana has shaped homeowners decision to patronize plastic-based ceiling panels. While the shift to the use of plastic-based panels has the potential to moderate the consumption levels of timber and therefore could contribute to the conservation of tropical forests, it has a negative implication on the development of local wood processing industry. One area where manufacturers of wood products such as wood panels can explore in order to increase or maintain the market share of wood-based panel products is sourcing raw timber from certified forests.
基金This research was supported by the National Science Foundation of China for Funding Projects (61173089,61472298) and National Statistical Science Program of China(2013LZ46).
文摘Public Key Encryption with Keyword Search (PEKS), an indispensable part of searchable encryption, is stock-in- trade for both protecting data and providing operability of encrypted data. So far most of PEKS schemes have been established on Identity-Based Cryptography (IBC) with key escrow problem inherently. Such problem severely restricts the promotion of IBC-based Public Key Infrastructure including PEKS component. Hence, Certificateless Public Key Cryptography (CLPKC) is efficient to remove such problem. CLPKC is introduced into PEKS, and a general model of Certificateless PEKS (CLPEKS) is formalized. In addition, a practical CLPEKS scheme is constructed with security and efficiency analyses. The proposal is secure channel free, and semantically secure against adaptive chosen keyword attack and keyword guessing attack. To illustrate the superiority, massive experiments are conducted on Enron Email dataset which is famous in information retrieval field. Compared with existed constructions, CLPEKS improves the efficiency in theory and removes the key escrow problem.
文摘A dynamic cooperation model of multi-agent is established by combining reinforcement learning with distributed artificial intelligence(DAI),in which the concept of individual optimization loses its meaning because of the dependence of repayment on each agent itself and the choice of other agents.Utilizing the idea of DAI,the intellectual unit of each robot and the change of task and environment,each agent can make decisions independently and finish various complicated tasks by communication and reciprocation between each other.The method is superior to other reinforcement learning methods commonly used in the multi-agent system.It can improve the convergence velocity of reinforcement learning,decrease requirements of computer memory,and enhance the capability of computing and logical ratiocinating for agent.The result of a simulated robot soccer match proves that the proposed cooperative strategy is valid.
文摘The paper deals on a significant retrofit project currently under construction of an existing hospital building in Avellino (Italy). The seismic retrofit was realized by connecting together the first floors of the three existing structures and by creating a unique isolation system composed of high damping rubber bearings and sliding devices. The base isolation is achieved by gradually cutting the building from foundation and installing the isolators at the level of upper edge of the columns. The study allows the verification of the adequacy of the isolation system, showing the benefits of the application of the isolation devices, the limitations and the characteristics of their performance.
文摘The corrective machining to compensate the resulting errors is usually tried at plural times based on the trial-and-error process when the machining is realized in die and mold manufacturing. This corrective machining has an influence on accuracy and efficiency and is an important factor. The measurement system for measuring the forms of die and mold at all times is essential in order to machine the die and mold with high accuracy and efficiency. However, the problems of management and operation errors are found in compensating process of die and mold machining. In this paper, an online machining and measurement system in die and mold manufacturing is developed in order to overcome these problems. In this online system, 2-axis control system is added to a surface roughness measuring instrument, and both NC machining program and measured data are linked and controlled using a same computer. Therefore, the machining and measurement can be recognized for consistent process, and can be realized on the machine. This system has the advantages such as the high accuracy, low-price, and online convenience and so on. The possibility of practical use of this online system was investigated by fundamental experiments.
基金Supported by the Program for National High-Tech Research and Development Program of China under Grant No 2007AA11Z233National Key Technology R & D Program under Grant No. 2009BAG13A06China Postdoctoral Science Foundation Funded Project under Grant No. 20090450395
文摘Different driving decisions will cause different processes of phase transition in traffic flow. To reveal the inner mechanism, this paper built a new cellular automaton (CA) model, based on the driving decision (DD). In the DD model, a driver's decision is divided into three stages: decision-making, action, and result. The acceleration is taken as a decision variable and three core factors, i.e. distance between adjacent vehicles, their own velocity, and the preceding vehicle's velocity, are considered. Simulation results show that the DD model can simulate the synchronized flow effectively and describe the phase transition in traffic flow well. Further analyses illustrate that various density will cause the phase transition and the random probability will impact the process. Compared with the traditional NaSch model, the DD model considered the preceding vehicle's velocity, the deceleration limitation, and a safe distance, so it can depict closer to the driver preferences on pursuing safety, stability and fuel-saving and has strong theoretical innovation for future studies.
基金Project(10YZ156) supported by Innovation Program of Shanghai Municipal Education Commission, China Project(sdl09009) supported by Training Program for Outstanding Youth Teacher of Shanghai Municipal Education Commission, China Project(Z2010-103) supported by Shanghai Education Development Foundation, China
文摘Two practical crawlspace heating systems introduced in detached houses have been chosen as a field study. One is the crawlspace warm air heating system and the other is the crawlspace hot water circulation system. Based on the field study result, by using the simulation sol, ware, THERB, the effectiveness of the crawlspace warm air heating system has been examined. The effect of the factors, such as the wind amount circulating between crawlspace and indoor space, foundation insulation condition, and heat amount into the crawlspace, on the indoor thermal environment has been analyzed. Based on these analyses, the measured crawlspace heating system can make the average temperature of the living room above 20℃. These two houses have excellent thermal environment. According to the simulating result, heat amount input into crawlspace, which can make comfortable indoor thermal environment, for every month in heating period has been roughly concluded, and they are 600 W in December and March and 800 W in February and January, respectively.
基金Project(50504019) supported by the National Natural Science Foundation of ChinaProject(2008BB4040) supported by the Science Foundation of Chongqing, ChinaProject(2008AA4028) supported by Scientific and Technological Project of Chongqing Science and Technology Commission, China
文摘Repeatedly unidirectional bending(RUB) was applied to the magnesium alloy sheet to improve the basal texture.The effect of RUB temperature on resulting structure and room temperature properties was investigated.The texture components of the sheet undergoing RUB at recovery temperature were similar to those of the sheet undergoing RUB at room temperature(RT).As the RUB temperature increased to above recrystallization temperature,the texture components became more disperse and the pyramidal components increased.With the increase of RUB temperature,the grain size near the surface of the sheets undergoing RUB tended to grow up.When the sheets were processed by RUB at medium-high temperature followed by annealing at 533 K,the yield strength and fracture elongation were lower than those of the cold rolled sheet;however,the Erichsen value was slightly higher than that of the cold rolled sheet.The sheet undergoing RUB at RT followed by annealing at 533 K represented the best mechanical properties.
基金Supported by National High Technology Research and Development Program ("863" Program, No. 2007AA042005)
文摘A unity transformation model (UTM) was presented for flexible NC machining of spiral bevel gears and hypoid gears. The model can support various machining methods for Gleason spiral bevel gears and hypoid gears, including generation machining and formation machining for wheel or pinion on a universal five-axis machining center, and then directly produce NC codes for the selected machining method. Wheel machining and pinion machining under UTM were simulated in Vericut 6.0 and tested on a five-axis machining center TDNC-W2000 with NC unit TDNC-H8. The results from simulation and real-cut verify the feasibility of gear machining under UTM as well as the correctness of NC codes.
文摘Cloud computing can offer a very powerful, reliable, predictable and scalable computing infrastructure for the execution of MAS (multi-agent systems) implementing complex agent-based applications such when modelling, simulation and real-time running of complex systems must be provided. Multi-agent systems appears as an adequate approach to current challenges in many areas. Between important qualities of MAS also belongs to, that they are open, interoperable, and heterogenous systems. The agent is active, a program entity, has its own ideas how to perform the tasks of the own agenda. Agents: perceive, behave "reasonably", act in the environment, communicate with other agents. Cloud infrastructures can offer an ideal platform where run MAS systems simulations, applications and real-time running because of its large amount of processing and memory resources that can be dynamically configured for executing large agent-based software at unprecedented scale. Cloud computing can help chemical and food companies drive operational excellence; meet growing and changing customer demands; accelerate new product innovation and ramp-to-volume manufacturing in key markets; reduce IT spending; manage and mitigate supply chain risks; and enable faster and more flexible delivery of new IT system. Production type of SOC (service-oriented computing) can be inspired by a "Cloud", for the production of "Cloud" offers an attractive and natural solutions in several computing trends such as delivery system over the Internet, use of utilities, flexibility, virtualization, a "grid" distributed computing, outsourcing, Web 2.0, etc.. Production of the "Cloud" is also considered as a new multidisciplinary field that includes "network" production, virtual manufacturing, agile manufacturing, and of course cloud computing. Examples of cloud computing and MAS applications in food and chemistry development and industry, proposition of using multi-agent systems in the control of batch processes, modified ACO (ant colony optimization) approach for the diversified service allocation and scheduling mechanism in cloud paradigma, examples of applications in a business area were studied in the paper.