Intermodal competition changes with changes in technology, economics, and environmental concerns. Trucks and airships are generally considered not to be competitors, but this depends on the distance of haul. The tonne...Intermodal competition changes with changes in technology, economics, and environmental concerns. Trucks and airships are generally considered not to be competitors, but this depends on the distance of haul. The tonne-kilometer cost of trucking rises much more quickly with distance than it does the cost of a cargo airship. At some distance, the two modes are direct substitutes. The costs of the Mexico-Canada refrigerated truck supply chain are compared with the costs of a 100t-lift, electrically-powered airship. The flight characteristics of the Hindenburg Zeppelin are used as a model for a modern cargo airship. The supply chain cost of trucking tomatoes is used to test the theorical proposition. The cost difference works out to about US10￠/kg (5￠/lb) advantage for trucking Mexican tomatoes to Canada. However, this cost disadvantage of the airship could be made up by their vibrationless ride, better air circulation and one-day service versus four days by truck. This alternative form of transportation could have a positive impact on worldwide north-south distribution of food. Airships can overcome trade barriers and distance to open new markets for perishable food exports. In addition, they would reduce the carbon emissions of transport. Canada imports 160,000 refrigerated truckloads of fruits and vegetables by from the southern US and Mexico. With an average driving distance of 3,000 km, these trucks emit 606,000 MT of CO<sub>2</sub> annually. Airships powered by hydrogen fuel cells would have zero-carbon emissions. Markets are not yet incorporating the environmental advantage of airships in any freight comparison, but inevitably this will be important.展开更多
The classical supply chain network(SCN)design problem is extended,where the candidate facilities are subject to failure and the products are prone to elapsed time deteriorion.First,the reliable SCN design problem is d...The classical supply chain network(SCN)design problem is extended,where the candidate facilities are subject to failure and the products are prone to elapsed time deteriorion.First,the reliable SCN design problem is defined by introducing the probability that a facility may be prone to inactivity based on the analysis of perishable product characteristics.The perishable product SCN design problem is formulated as a 0-1 integer programming model.The objective is to minimize the weighted sum of the operating cost(the fixed plus transportation cost)and the expected failure cost.And then,the perishable product SCN design model is discussed and solved using the genetic algorithm(GA).The results show how to generate the tradeoff curve between the operating costs and the expected failure costs.And these tradeoff curves demonstrate empirically that substantial improvements in reliability are often possible with minimal increase in the operating costs.展开更多
被引分析是最常见的科学计量学研究方法,主要用来证明作者或其成果在所属专业领域内的影响力。Publish or Perish是一种在线被引分析软件,依据Google Scholar数据库来查询作者或成果的被引次数,并提供相关的统计数据分析。文章主要介绍...被引分析是最常见的科学计量学研究方法,主要用来证明作者或其成果在所属专业领域内的影响力。Publish or Perish是一种在线被引分析软件,依据Google Scholar数据库来查询作者或成果的被引次数,并提供相关的统计数据分析。文章主要介绍了该工具的功能及使用方法,并结合实例探讨了其在外语教学研究中的应用。展开更多
There is still no effective means to analyze in depth and utilize domestic mass data about agricultural product quality safety tests in china now. The neural network algorithm, the classification regression tree algor...There is still no effective means to analyze in depth and utilize domestic mass data about agricultural product quality safety tests in china now. The neural network algorithm, the classification regression tree algorithm, the Bayesian network algorithm were selected according to the principle of selecting combination model and were used to build models respectively and then combined, innovatively establishing a combination model which has relatively high precision, strong robustness and better explanatory to predict the results of perishable food transportation meta-morphism monitoring. The relative optimal prediction model of the perishable food transportation metamorphism monitoring system could be got. The relative perfect prediction model can guide the actual sampling work about food quality and safety by prognosticating the occurrence of unqualified food to select the typical and effective samples for test, thus improving the efficiency and effectiveness of sampling work effectively, so as to avoid deteriorated perishable food’s approaching the market to ensure the quality and safety of perishable food transportation. A solid protective wall was built in the protection of general perishable food consumers’ health.展开更多
This paper presents an economic lot-sizing problem with perishable inventory and general economies of scale cost functions. For the case with backlogging allowed, a mathematical model is formulated, and several proper...This paper presents an economic lot-sizing problem with perishable inventory and general economies of scale cost functions. For the case with backlogging allowed, a mathematical model is formulated, and several properties of the optimal solutions are explored. With the help of these optimality properties, a polynomial time approximation algorithm is developed by a new method. The new method adopts a shift technique to obtain a feasible solution of subproblem and takes the optimal solution of the subproblem as an approximation solution of our problem. The worst case performance for the approximation algorithm is proven to be （4√2 ＋ 5）/7. Finally, an instance illustrates that the bound is tight.展开更多
The amount of perishable products transported via the existing intermodal freight networks has significantly increased over the last years. Perishable products tend to decay due to a wide range of external factors. Su...The amount of perishable products transported via the existing intermodal freight networks has significantly increased over the last years. Perishable products tend to decay due to a wide range of external factors. Supply chain operations mismanagement causes waste of substantial volumes of perishable products every year. The heretofore proposed mathematical models optimize certain supply chain processes and reduce decay of perishable products, but primarily deal with local production, inventory, distribution, and retailing of perishable products. However, significant quantities of perishable products are delivered from different continents, which shall increase the total transportation time and decay potential of perishable products as compared to local deliveries. This paper proposes a novel optimization model to design the intermodal freight network for both local and long-haul deliveries of perishable products. The objective of the model aims to minimize the total cost associated with transportation and decay of perishable products. A set of piecewise approximations are applied to linearize the non-linear decay function for each perishable product type. CPLEX is used to solve the problem. Comprehensive numerical experiments are conducted using the intermodal freight network for import of the seafood perishable products to the United States to draw important managerial insights. Results demonstrate that increasing product decay cost may significantly change the design of intermodal freight network for transport of perishable products, cause modal shifts and affect the total transportation time and associated costs.展开更多
Chemical application after harvest is an important method to preserve strawberry fruit quality and extend shelf life. The strawberry fruits harvested at red stage were treated with three different sources of calcium, ...Chemical application after harvest is an important method to preserve strawberry fruit quality and extend shelf life. The strawberry fruits harvested at red stage were treated with three different sources of calcium, i.e., calcium nitrate, calcium gluconate and calcium chloride at calcium concentration of 0% （distilled water）, 0.5%, 1.0% and 1.5%. The strawberry fruits were dipped for 30 s. The calcium sources, calcium concentration and the interaction of calcium sources and calcium concentration significantly affected the storage performance of strawberry fruits. All the three sources and concentrations were effective in decreasing the storage associated changes, i.e., weight loss, decline in marketable fruits, loss of organoleptic quality, increase in total soluble solids （TSS）, decline in reducing sugars, total sugars, acidity and increase in sugar/acid ratio in strawberry fruit, thus extending the shelf life. Calcium gluconate at 1.5% calcium concentration was more effective. Treatment of strawberry fruit with 1.5% calcium from calcium gluconate source resulted in the highest number of marketable fruit （100%）, extended shelf life （10 d）, and total soluble solid （7.80%） with the minimum weight loss （5.45%）. Calcium dips result in higher calcium concentration in strawberry fruits, which delays ripening in fruits by maintaining the structure and function of cell walls and membranes. It can be concluded that calcium gluconate at 1.5% concentration is an effective calcium treatment to retain the quality and extend the shelf life of strawberry fruit.展开更多
The purpose of this paper is to present a critical review of prior literature relating to agri-food supply chain management. An in-depth analysis has been carried out to identify the influential information from the l...The purpose of this paper is to present a critical review of prior literature relating to agri-food supply chain management. An in-depth analysis has been carried out to identify the influential information from the literature. This paper has identified gaps to be explored about agricultural supply chain management (SCM) practices which may be used by researchers to enrich theory construction and practitioners may concentrate on establishing the extent and frontiers of agri-food SCM. This research work is the first attempt to make a critical literature review of available literature on agri-food SCM practices for developing countries like India. The research articles and other materials related to the agri-food supply chain management were collected from online data bases like Scopus, EBSCO and Google Scholar for the period of 10 years (2006-2016). The study performs content analysis and is followed by descriptive analysis. In the next phase, the literature in the field of agri-food supply chain management is classified into four broad categories viz. general literature review of agri-food supply chain, policies affecting the segments of agri-food supply chain, individual segments of agri-food SCM (structure of supply chain segments and conduct of supply chain segments) and performance of supply chain segments. These four categories are comprehensively reviewed and elaborated the research gap in the literature based on agri-food supply chain management. Finally, potato supply chain of India is considered as a case example for comprehensive analysis and elaborated in detail.展开更多
The Internet of Things (IoTs) is apace growing, billions of IoT devicesare connected to the Internet which communicate and exchange data among eachother. Applications of IoT can be found in many fields of engineering ...The Internet of Things (IoTs) is apace growing, billions of IoT devicesare connected to the Internet which communicate and exchange data among eachother. Applications of IoT can be found in many fields of engineering and sciencessuch as healthcare, traffic, agriculture, oil and gas industries, and logistics. Inlogistics, the products which are to be transported may be sensitive and perishable, and require controlled environment. Most of the commercially availablelogistic containers are not integrated with IoT devices to provide controlled environment parameters inside the container and to transmit data to a remote server.This necessitates the need for designing and fabricating IoT based smart containers. Due to constrained nature of IoT devices, these are prone to different cybersecurity attacks such as Denial of Service (DoS), Man in Middle (MITM) andReplay. Therefore, designing efficient cyber security framework are required forsmart container. The Datagram Transport Layer Security (DTLS) Protocol hasemerged as the de facto standard for securing communication in IoT devices.However, it is unable to minimize cyber security attacks such as Denial of Serviceand Distributed Denial of Service (DDoS) during the handshake process. Themain contribution of this paper is to design a cyber secure framework by implementing novel hybrid DTLS protocol in smart container which can efficientlyminimize the effects of cyber attacks during handshake process. The performanceof our proposed framework is evaluated in terms of energy efficiency, handshaketime, throughput and packet delivery ratio. Moreover, the proposed framework istested in IoT based smart containers. The proposed framework decreases handshake time more than 9% and saves 11% of energy efficiency for transmissionin compare of the standard DTLS, while increases packet delivery ratio andthroughput by 83% and 87% respectively.展开更多
This paper considers the two-echelon supply chain system which consists of single agricultural producers and retailers,and analyzes the impact of sharing ratio on the option ordering quantity,and retailers and produce...This paper considers the two-echelon supply chain system which consists of single agricultural producers and retailers,and analyzes the impact of sharing ratio on the option ordering quantity,and retailers and producers' expected profits.Studies have shown that in the case of decentralization,when the revenue sharing ratio is between 0 and 0.3,the option ordering quantity of farm produce is a decreasing function of the sharing ratio; when the revenue sharing ratio is between 0.3 and 1,the option ordering quantity of farm produce is an increasing function of sharing ratio; when the revenue sharing ratio is between 0.421 and 1,the agricultural producers and retailers' expected profits are an increasing function of sharing ratio.Finally,through the numerical calculation,the applicability of the conclusions is verified,to provide a reference for the supply chain management practices.展开更多
In the classical inventory models, it is assumed that the retailer pays to the supplier as soon as he received the items and in such cases the supplier offers a cash discount or credit period (permis-sible delay) to t...In the classical inventory models, it is assumed that the retailer pays to the supplier as soon as he received the items and in such cases the supplier offers a cash discount or credit period (permis-sible delay) to the retailer. In this paper we presented an inventory model for perishable items with time varying stock dependent demand under inflation. It is assumed that the supplier offers a credit period to the retailer and the length of credit period is dependent on the order quantity. The purpose of our study is to minimize the present value of retailer’s total cost. Numerical examples are also given to demonstrate the presented mode.展开更多
Despite the government expanding PhD enrollment,students face limited mentorship and pressure to publish in order to graduate.As they struggle,many find their degrees losing value amid rising societal expectations for...Despite the government expanding PhD enrollment,students face limited mentorship and pressure to publish in order to graduate.As they struggle,many find their degrees losing value amid rising societal expectations for talent.展开更多
The carbon emission from the wastage of deteriorating items is very harmful to the environment.In general,it is believed that every item in a lot size is of high quality but practically it may not be possible that all...The carbon emission from the wastage of deteriorating items is very harmful to the environment.In general,it is believed that every item in a lot size is of high quality but practically it may not be possible that all products are of excellent quality.The deteriorating items may have a high deterioration rate and deteriorate as time passes.They can be managed with the help of preservation technologies,but involving high cost.Furthermore,shortages arise due to the deterioration of commodities,consequently influencing the demand for the product.The objective of the study is to examine the impact of carbon emission and the pattern of demand due to a shortage of products on the retailer’s total profit with the passage of time.Also,trade credit policies play a vital role for buyers and sellers and consequently impact overall profitability.Considering the importance of these factors,we have proposed a profit maximization model which incorporates trade-credit financing policy,carbon emissions,and the learning effect.This study examines how the learning effects impact the deteriorating items when trade-credit financing takes place.Detailed sensitivity analysis and numerical examples are presented to analyse the impact of model parameters on profit function.The application,future work,and managerial insight have been presented in this proposed study.展开更多
Consumers pay more and more attention to the quality of perishable roods, which is mainly affected by storage temperature. This paper presents a dynamic pricing model for perishable foods under temperature control. To...Consumers pay more and more attention to the quality of perishable roods, which is mainly affected by storage temperature. This paper presents a dynamic pricing model for perishable foods under temperature control. To maximize the total profit, the optimal price and storage temperature are obtained using Pontryagin＇s maximum principle. A static pricing model is provided to compare with the dynamic one. It is shown by a numerical example that the dynamic policy can make more revenue than the static one. Moreover, the managerial implications are analyzed and the effectiveness of the proposed method is demonstrated.展开更多
Numerous empirical studies show that advertising effort can stimulate demand in both current and future periods, and there is an interaction between pricing, advertising and ordering decisions. How do these decisions ...Numerous empirical studies show that advertising effort can stimulate demand in both current and future periods, and there is an interaction between pricing, advertising and ordering decisions. How do these decisions interact with each other and what is the effect of advertising on pricing and ordering decisions？ To understand this interaction, we consider a newsvendor-type firm that sells a perishable product in a stable market and dynamically determines the joint ordering, pricing and advertising strategies. The problem is modeled as an infmite horizon newsvendor problem with an advertising carryover effect and price-sensitive demand. We characterize the optimal pricing, advertising and inventory strategies and their comparative statics, and consider how this policy differs from the traditional approach without the advertising effect. We show that the optimal effective advertising level is monotonically increasing with the effective advertising level in the previous period, and hence the optimal strategies （advertising, pricing, inventory level） globally converge to the steady states in the long run. We numerically show that the optimal policy can reap significant profit, which underscores the importance of the advertising-driven ordering and pricing strategies.展开更多
This study investigated an economic order quantity (EOQ) model with completebackorder for fixed lifetime perishable items under multiple advance and delayedpayments policies. Here, a new type of business policy is con...This study investigated an economic order quantity (EOQ) model with completebackorder for fixed lifetime perishable items under multiple advance and delayedpayments policies. Here, a new type of business policy is consideredwhere supplieroffers the retailer to pay a fraction of the purchasing cost before the order deliverybymultiple equal installments starting from the ordering time and the rest amountafter the delivery by multiple equal installments. Here, some theoretical results areillustrated to determine the conditions of existence and uniqueness of the optimalsolutions. A closed form solution is determined to solve the proposed model underapproximation. Some numerical examples are provided to examine the validity ofthe proposed model. Finally, sensitivity analyses are presented to obtain the effectof optimal policy and provide some managerial insights of the model.展开更多
Although food availability and the abundance of seed predators have been postulated to affect seed dispersal,it is not clear how seed-eating animals modify their scatter-hoarding strategies in response to different le...Although food availability and the abundance of seed predators have been postulated to affect seed dispersal,it is not clear how seed-eating animals modify their scatter-hoarding strategies in response to different levels of interspecific competition.We placed paired germinated and ungerminated acorns of Quercus mongolica on 30-cm high platforms to exclude potential interspecific competition of the predominant larder hoarders Apodemus peninsulae and Myodes rufocanus,to investigate seed dispersal by a predominant scatter-hoarder,Tamias sibiricus,in the field in north-eastern China.Our results showed that T.sibiricus ate more acorns in situ in the absence of interspecific competition.In the presence of interspecific competition of A.peninsulae and C.rufocanus,however,more acorns were scatter-hoarded by T.sibiricus.Regardless of interspecific competition,germination of acorns showed no significant effects on seed dispersal patterns,inconsistent with the“seed perishability hypothesis”that animals avoid hoarding seeds with high perishability.Exclusion of interspecific competition,though relatively increasing the per capita seed abundance,appears to reduce seed dispersal,scatter-hoarding and seedling establishment.Therefore,we propose that moderate interspecific competition rather than competition exclusion may benefit seed scatter-hoarding and seedling establishment.展开更多
Chitosan edible coating(Ch;2%,mass concentration)enriched with 2%of 0.1 mg/L Bidens pilosa(Ch+B),Lippia javanica(Ch+L),Syzygium cordatum(Ch+S),or Ximenia caffra(Ch+X)was applied as a composite edible coating in allevi...Chitosan edible coating(Ch;2%,mass concentration)enriched with 2%of 0.1 mg/L Bidens pilosa(Ch+B),Lippia javanica(Ch+L),Syzygium cordatum(Ch+S),or Ximenia caffra(Ch+X)was applied as a composite edible coating in alleviating shrivel and maintaining the quality of purple passion fruit(Passiflora edulis var.Ester).Treated fruit was dipped for 3 min in the coating solution,and control fruit was dipped in distilled water.The fruit were stored at(8±2)℃and 90%±5%relative humidity(RH)for 32 d.Sampling was done every 8 d plus 3 d(20±2)℃and(50%±5%)RH to simulate retail conditions.Efficacy of medicinal plant extracts in the chitosan matrix varied;lower ethylene production(82.42μL C_(2)H_(4)/(kg·h))was seen in fruit coated with Ch+S,and the lowest respiration rate(75 mL CO_(2)/(kg·h))was observed in fruit coated with Ch+B.The control fruit showed the highest ethylene production(84.90μL C_(2)H_(4)/(kg·h))and respiration rate(117.98 mL CO_(2)/(kg·h)).Fruit coated with Ch+B had the lowest weight loss(41.67%),higher juice content(60.13%)and BrimA(3.31);while the control fruit had the highest weight loss(88.03%),lowest juice content(21.90%),and BrimA(2.49).Shrivel incidence was lowest(23.70%)on fruit coated with Ch+L and highest(83.30%)on the control fruit.Fruit coated with Ch+X had the lowest electrolyte leakage(71.40%),while the control fruit had the highest(91.97%).Fruit coated with chitosan alone performed better than the control fruit but did not exceed the quality of composite chitosan-coated fruit.Based on the principal component analysis,it can be concluded that passion fruit coated with Ch+B was more effective in alleviating shrivel incidence,better maintained the quality ofpassion fruit duringstorage,andshows potential for commercial applications.展开更多
Food traceability is a critical factor that can ensure food safety for enhancing the credibility of the product,thus achieving heightened user satisfaction and loyalty.The Perishable Food SC(PFSC)requires paramount ca...Food traceability is a critical factor that can ensure food safety for enhancing the credibility of the product,thus achieving heightened user satisfaction and loyalty.The Perishable Food SC(PFSC)requires paramount care for ensuring quality owing to the limited product life.The PFSC comprises of multiple organizations with varied interests and is more likely to be hesitant in sharing the traceability details among one another owing to a lack of trust,which can be overcome by using Blockchain(BC).In this research,an efficient scheme using BC-Deep Residual Network(BC-DRN)is developed to provide food traceability for dairy products.Here,food traceability is determined by using various modules,like the Internet of Things(IoT),BC data management,Food traceability BC architecture,and DRN-based food quality evaluation modules.The devised BC-DRN-based food quality traceability system is examined based on its performance metrics,like sensitivity,response time,and testing accuracy,and it has attained better values of 0.939,109.564 s,and 0.931.展开更多
The supply chain of perishable products is a combination of information organization,sharing and integration.The information modeling of supply chain is constructed to abstract key quality information including enviro...The supply chain of perishable products is a combination of information organization,sharing and integration.The information modeling of supply chain is constructed to abstract key quality information including environment information,processing procedures and product quality assessments based on principle of quality safety factors and property of decay rate.The coloured Petri Net is applied for integrated description of independent information classification,aiming at risk identification and risk management framework.Well,according to the quality deterioration tendency,risk grades management and decision-making system are established.Practically,the circulation system of aquatic products is studied in this paper for full processing description.The simulation experiments are manipulated on environmental information,processing information and product quality information by the coloured Petri Net.Eventually,the conclusion turns out precisely as such that the coloured Petri Net conclusive for information classification and information transmission while integrated information management is available of efficient risk identification and decision-making system in supply chain of perishable products.Meanwhile,the validity of evaluating management and shelf-life estimation of perishable products are technically feasible.展开更多
文摘Intermodal competition changes with changes in technology, economics, and environmental concerns. Trucks and airships are generally considered not to be competitors, but this depends on the distance of haul. The tonne-kilometer cost of trucking rises much more quickly with distance than it does the cost of a cargo airship. At some distance, the two modes are direct substitutes. The costs of the Mexico-Canada refrigerated truck supply chain are compared with the costs of a 100t-lift, electrically-powered airship. The flight characteristics of the Hindenburg Zeppelin are used as a model for a modern cargo airship. The supply chain cost of trucking tomatoes is used to test the theorical proposition. The cost difference works out to about US10￠/kg (5￠/lb) advantage for trucking Mexican tomatoes to Canada. However, this cost disadvantage of the airship could be made up by their vibrationless ride, better air circulation and one-day service versus four days by truck. This alternative form of transportation could have a positive impact on worldwide north-south distribution of food. Airships can overcome trade barriers and distance to open new markets for perishable food exports. In addition, they would reduce the carbon emissions of transport. Canada imports 160,000 refrigerated truckloads of fruits and vegetables by from the southern US and Mexico. With an average driving distance of 3,000 km, these trucks emit 606,000 MT of CO<sub>2</sub> annually. Airships powered by hydrogen fuel cells would have zero-carbon emissions. Markets are not yet incorporating the environmental advantage of airships in any freight comparison, but inevitably this will be important.
基金The National Key Technology R&D Program of China during the 11th Five-Year Plan Period(No.2006BAH02A06)
文摘The classical supply chain network(SCN)design problem is extended,where the candidate facilities are subject to failure and the products are prone to elapsed time deteriorion.First,the reliable SCN design problem is defined by introducing the probability that a facility may be prone to inactivity based on the analysis of perishable product characteristics.The perishable product SCN design problem is formulated as a 0-1 integer programming model.The objective is to minimize the weighted sum of the operating cost(the fixed plus transportation cost)and the expected failure cost.And then,the perishable product SCN design model is discussed and solved using the genetic algorithm(GA).The results show how to generate the tradeoff curve between the operating costs and the expected failure costs.And these tradeoff curves demonstrate empirically that substantial improvements in reliability are often possible with minimal increase in the operating costs.
文摘被引分析是最常见的科学计量学研究方法,主要用来证明作者或其成果在所属专业领域内的影响力。Publish or Perish是一种在线被引分析软件,依据Google Scholar数据库来查询作者或成果的被引次数,并提供相关的统计数据分析。文章主要介绍了该工具的功能及使用方法,并结合实例探讨了其在外语教学研究中的应用。
文摘There is still no effective means to analyze in depth and utilize domestic mass data about agricultural product quality safety tests in china now. The neural network algorithm, the classification regression tree algorithm, the Bayesian network algorithm were selected according to the principle of selecting combination model and were used to build models respectively and then combined, innovatively establishing a combination model which has relatively high precision, strong robustness and better explanatory to predict the results of perishable food transportation meta-morphism monitoring. The relative optimal prediction model of the perishable food transportation metamorphism monitoring system could be got. The relative perfect prediction model can guide the actual sampling work about food quality and safety by prognosticating the occurrence of unqualified food to select the typical and effective samples for test, thus improving the efficiency and effectiveness of sampling work effectively, so as to avoid deteriorated perishable food’s approaching the market to ensure the quality and safety of perishable food transportation. A solid protective wall was built in the protection of general perishable food consumers’ health.
基金supported by National Natural Science Foundation of China (No. 10671108 and 70971076)Found for the Doctoral Program of Higher Education of Ministry of Education of China (No. 20070446001)+1 种基金Innovation Planning Project of Shandong Province (No. SDYY06034)Foundation of Qufu Normal University (No. XJZ200849)
文摘This paper presents an economic lot-sizing problem with perishable inventory and general economies of scale cost functions. For the case with backlogging allowed, a mathematical model is formulated, and several properties of the optimal solutions are explored. With the help of these optimality properties, a polynomial time approximation algorithm is developed by a new method. The new method adopts a shift technique to obtain a feasible solution of subproblem and takes the optimal solution of the subproblem as an approximation solution of our problem. The worst case performance for the approximation algorithm is proven to be （4√2 ＋ 5）/7. Finally, an instance illustrates that the bound is tight.
文摘The amount of perishable products transported via the existing intermodal freight networks has significantly increased over the last years. Perishable products tend to decay due to a wide range of external factors. Supply chain operations mismanagement causes waste of substantial volumes of perishable products every year. The heretofore proposed mathematical models optimize certain supply chain processes and reduce decay of perishable products, but primarily deal with local production, inventory, distribution, and retailing of perishable products. However, significant quantities of perishable products are delivered from different continents, which shall increase the total transportation time and decay potential of perishable products as compared to local deliveries. This paper proposes a novel optimization model to design the intermodal freight network for both local and long-haul deliveries of perishable products. The objective of the model aims to minimize the total cost associated with transportation and decay of perishable products. A set of piecewise approximations are applied to linearize the non-linear decay function for each perishable product type. CPLEX is used to solve the problem. Comprehensive numerical experiments are conducted using the intermodal freight network for import of the seafood perishable products to the United States to draw important managerial insights. Results demonstrate that increasing product decay cost may significantly change the design of intermodal freight network for transport of perishable products, cause modal shifts and affect the total transportation time and associated costs.
文摘Chemical application after harvest is an important method to preserve strawberry fruit quality and extend shelf life. The strawberry fruits harvested at red stage were treated with three different sources of calcium, i.e., calcium nitrate, calcium gluconate and calcium chloride at calcium concentration of 0% （distilled water）, 0.5%, 1.0% and 1.5%. The strawberry fruits were dipped for 30 s. The calcium sources, calcium concentration and the interaction of calcium sources and calcium concentration significantly affected the storage performance of strawberry fruits. All the three sources and concentrations were effective in decreasing the storage associated changes, i.e., weight loss, decline in marketable fruits, loss of organoleptic quality, increase in total soluble solids （TSS）, decline in reducing sugars, total sugars, acidity and increase in sugar/acid ratio in strawberry fruit, thus extending the shelf life. Calcium gluconate at 1.5% calcium concentration was more effective. Treatment of strawberry fruit with 1.5% calcium from calcium gluconate source resulted in the highest number of marketable fruit （100%）, extended shelf life （10 d）, and total soluble solid （7.80%） with the minimum weight loss （5.45%）. Calcium dips result in higher calcium concentration in strawberry fruits, which delays ripening in fruits by maintaining the structure and function of cell walls and membranes. It can be concluded that calcium gluconate at 1.5% concentration is an effective calcium treatment to retain the quality and extend the shelf life of strawberry fruit.
文摘The purpose of this paper is to present a critical review of prior literature relating to agri-food supply chain management. An in-depth analysis has been carried out to identify the influential information from the literature. This paper has identified gaps to be explored about agricultural supply chain management (SCM) practices which may be used by researchers to enrich theory construction and practitioners may concentrate on establishing the extent and frontiers of agri-food SCM. This research work is the first attempt to make a critical literature review of available literature on agri-food SCM practices for developing countries like India. The research articles and other materials related to the agri-food supply chain management were collected from online data bases like Scopus, EBSCO and Google Scholar for the period of 10 years (2006-2016). The study performs content analysis and is followed by descriptive analysis. In the next phase, the literature in the field of agri-food supply chain management is classified into four broad categories viz. general literature review of agri-food supply chain, policies affecting the segments of agri-food supply chain, individual segments of agri-food SCM (structure of supply chain segments and conduct of supply chain segments) and performance of supply chain segments. These four categories are comprehensively reviewed and elaborated the research gap in the literature based on agri-food supply chain management. Finally, potato supply chain of India is considered as a case example for comprehensive analysis and elaborated in detail.
基金funded by the Higher Education Commission(HEC),Pakistan through its initiative of National Center for Cyber Security for the affiliated Innovative Secured Systems Lab(ISSL)University of Engineering&Technology(UET)Peshawar,Grant No:2(1078)/HEC/M&E/2018/70.
文摘The Internet of Things (IoTs) is apace growing, billions of IoT devicesare connected to the Internet which communicate and exchange data among eachother. Applications of IoT can be found in many fields of engineering and sciencessuch as healthcare, traffic, agriculture, oil and gas industries, and logistics. Inlogistics, the products which are to be transported may be sensitive and perishable, and require controlled environment. Most of the commercially availablelogistic containers are not integrated with IoT devices to provide controlled environment parameters inside the container and to transmit data to a remote server.This necessitates the need for designing and fabricating IoT based smart containers. Due to constrained nature of IoT devices, these are prone to different cybersecurity attacks such as Denial of Service (DoS), Man in Middle (MITM) andReplay. Therefore, designing efficient cyber security framework are required forsmart container. The Datagram Transport Layer Security (DTLS) Protocol hasemerged as the de facto standard for securing communication in IoT devices.However, it is unable to minimize cyber security attacks such as Denial of Serviceand Distributed Denial of Service (DDoS) during the handshake process. Themain contribution of this paper is to design a cyber secure framework by implementing novel hybrid DTLS protocol in smart container which can efficientlyminimize the effects of cyber attacks during handshake process. The performanceof our proposed framework is evaluated in terms of energy efficiency, handshaketime, throughput and packet delivery ratio. Moreover, the proposed framework istested in IoT based smart containers. The proposed framework decreases handshake time more than 9% and saves 11% of energy efficiency for transmissionin compare of the standard DTLS, while increases packet delivery ratio andthroughput by 83% and 87% respectively.
基金Supported by National Natural Science Foundation of China(7093200571102055)+1 种基金Youth Fund Project of Sichuan Provincial Department of Education(13ZB003514ZA0304)
文摘This paper considers the two-echelon supply chain system which consists of single agricultural producers and retailers,and analyzes the impact of sharing ratio on the option ordering quantity,and retailers and producers' expected profits.Studies have shown that in the case of decentralization,when the revenue sharing ratio is between 0 and 0.3,the option ordering quantity of farm produce is a decreasing function of the sharing ratio; when the revenue sharing ratio is between 0.3 and 1,the option ordering quantity of farm produce is an increasing function of sharing ratio; when the revenue sharing ratio is between 0.421 and 1,the agricultural producers and retailers' expected profits are an increasing function of sharing ratio.Finally,through the numerical calculation,the applicability of the conclusions is verified,to provide a reference for the supply chain management practices.
文摘In the classical inventory models, it is assumed that the retailer pays to the supplier as soon as he received the items and in such cases the supplier offers a cash discount or credit period (permis-sible delay) to the retailer. In this paper we presented an inventory model for perishable items with time varying stock dependent demand under inflation. It is assumed that the supplier offers a credit period to the retailer and the length of credit period is dependent on the order quantity. The purpose of our study is to minimize the present value of retailer’s total cost. Numerical examples are also given to demonstrate the presented mode.
文摘Despite the government expanding PhD enrollment,students face limited mentorship and pressure to publish in order to graduate.As they struggle,many find their degrees losing value amid rising societal expectations for talent.
文摘The carbon emission from the wastage of deteriorating items is very harmful to the environment.In general,it is believed that every item in a lot size is of high quality but practically it may not be possible that all products are of excellent quality.The deteriorating items may have a high deterioration rate and deteriorate as time passes.They can be managed with the help of preservation technologies,but involving high cost.Furthermore,shortages arise due to the deterioration of commodities,consequently influencing the demand for the product.The objective of the study is to examine the impact of carbon emission and the pattern of demand due to a shortage of products on the retailer’s total profit with the passage of time.Also,trade credit policies play a vital role for buyers and sellers and consequently impact overall profitability.Considering the importance of these factors,we have proposed a profit maximization model which incorporates trade-credit financing policy,carbon emissions,and the learning effect.This study examines how the learning effects impact the deteriorating items when trade-credit financing takes place.Detailed sensitivity analysis and numerical examples are presented to analyse the impact of model parameters on profit function.The application,future work,and managerial insight have been presented in this proposed study.
基金supported by the National Natural Science Foundation of China No.71371133,No.61004015,No.61473204the Program for New Century Excellent Talents in Universities of China(NCET11-0377)
文摘Consumers pay more and more attention to the quality of perishable roods, which is mainly affected by storage temperature. This paper presents a dynamic pricing model for perishable foods under temperature control. To maximize the total profit, the optimal price and storage temperature are obtained using Pontryagin＇s maximum principle. A static pricing model is provided to compare with the dynamic one. It is shown by a numerical example that the dynamic policy can make more revenue than the static one. Moreover, the managerial implications are analyzed and the effectiveness of the proposed method is demonstrated.
文摘Numerous empirical studies show that advertising effort can stimulate demand in both current and future periods, and there is an interaction between pricing, advertising and ordering decisions. How do these decisions interact with each other and what is the effect of advertising on pricing and ordering decisions？ To understand this interaction, we consider a newsvendor-type firm that sells a perishable product in a stable market and dynamically determines the joint ordering, pricing and advertising strategies. The problem is modeled as an infmite horizon newsvendor problem with an advertising carryover effect and price-sensitive demand. We characterize the optimal pricing, advertising and inventory strategies and their comparative statics, and consider how this policy differs from the traditional approach without the advertising effect. We show that the optimal effective advertising level is monotonically increasing with the effective advertising level in the previous period, and hence the optimal strategies （advertising, pricing, inventory level） globally converge to the steady states in the long run. We numerically show that the optimal policy can reap significant profit, which underscores the importance of the advertising-driven ordering and pricing strategies.
文摘This study investigated an economic order quantity (EOQ) model with completebackorder for fixed lifetime perishable items under multiple advance and delayedpayments policies. Here, a new type of business policy is consideredwhere supplieroffers the retailer to pay a fraction of the purchasing cost before the order deliverybymultiple equal installments starting from the ordering time and the rest amountafter the delivery by multiple equal installments. Here, some theoretical results areillustrated to determine the conditions of existence and uniqueness of the optimalsolutions. A closed form solution is determined to solve the proposed model underapproximation. Some numerical examples are provided to examine the validity ofthe proposed model. Finally, sensitivity analyses are presented to obtain the effectof optimal policy and provide some managerial insights of the model.
基金the National Natural Science Foundation of China(31760156)the Young Talents Invitation Program of Shandong Provincial Colleges and Universities.
文摘Although food availability and the abundance of seed predators have been postulated to affect seed dispersal,it is not clear how seed-eating animals modify their scatter-hoarding strategies in response to different levels of interspecific competition.We placed paired germinated and ungerminated acorns of Quercus mongolica on 30-cm high platforms to exclude potential interspecific competition of the predominant larder hoarders Apodemus peninsulae and Myodes rufocanus,to investigate seed dispersal by a predominant scatter-hoarder,Tamias sibiricus,in the field in north-eastern China.Our results showed that T.sibiricus ate more acorns in situ in the absence of interspecific competition.In the presence of interspecific competition of A.peninsulae and C.rufocanus,however,more acorns were scatter-hoarded by T.sibiricus.Regardless of interspecific competition,germination of acorns showed no significant effects on seed dispersal patterns,inconsistent with the“seed perishability hypothesis”that animals avoid hoarding seeds with high perishability.Exclusion of interspecific competition,though relatively increasing the per capita seed abundance,appears to reduce seed dispersal,scatter-hoarding and seedling establishment.Therefore,we propose that moderate interspecific competition rather than competition exclusion may benefit seed scatter-hoarding and seedling establishment.
基金supported by the National Research Foundation of South Africa (No.129295)the University Research Council at the University of Johannesburg,South Africa.
文摘Chitosan edible coating(Ch;2%,mass concentration)enriched with 2%of 0.1 mg/L Bidens pilosa(Ch+B),Lippia javanica(Ch+L),Syzygium cordatum(Ch+S),or Ximenia caffra(Ch+X)was applied as a composite edible coating in alleviating shrivel and maintaining the quality of purple passion fruit(Passiflora edulis var.Ester).Treated fruit was dipped for 3 min in the coating solution,and control fruit was dipped in distilled water.The fruit were stored at(8±2)℃and 90%±5%relative humidity(RH)for 32 d.Sampling was done every 8 d plus 3 d(20±2)℃and(50%±5%)RH to simulate retail conditions.Efficacy of medicinal plant extracts in the chitosan matrix varied;lower ethylene production(82.42μL C_(2)H_(4)/(kg·h))was seen in fruit coated with Ch+S,and the lowest respiration rate(75 mL CO_(2)/(kg·h))was observed in fruit coated with Ch+B.The control fruit showed the highest ethylene production(84.90μL C_(2)H_(4)/(kg·h))and respiration rate(117.98 mL CO_(2)/(kg·h)).Fruit coated with Ch+B had the lowest weight loss(41.67%),higher juice content(60.13%)and BrimA(3.31);while the control fruit had the highest weight loss(88.03%),lowest juice content(21.90%),and BrimA(2.49).Shrivel incidence was lowest(23.70%)on fruit coated with Ch+L and highest(83.30%)on the control fruit.Fruit coated with Ch+X had the lowest electrolyte leakage(71.40%),while the control fruit had the highest(91.97%).Fruit coated with chitosan alone performed better than the control fruit but did not exceed the quality of composite chitosan-coated fruit.Based on the principal component analysis,it can be concluded that passion fruit coated with Ch+B was more effective in alleviating shrivel incidence,better maintained the quality ofpassion fruit duringstorage,andshows potential for commercial applications.
文摘Food traceability is a critical factor that can ensure food safety for enhancing the credibility of the product,thus achieving heightened user satisfaction and loyalty.The Perishable Food SC(PFSC)requires paramount care for ensuring quality owing to the limited product life.The PFSC comprises of multiple organizations with varied interests and is more likely to be hesitant in sharing the traceability details among one another owing to a lack of trust,which can be overcome by using Blockchain(BC).In this research,an efficient scheme using BC-Deep Residual Network(BC-DRN)is developed to provide food traceability for dairy products.Here,food traceability is determined by using various modules,like the Internet of Things(IoT),BC data management,Food traceability BC architecture,and DRN-based food quality evaluation modules.The devised BC-DRN-based food quality traceability system is examined based on its performance metrics,like sensitivity,response time,and testing accuracy,and it has attained better values of 0.939,109.564 s,and 0.931.
基金This work was supported by the National Natural Science Foundation of China(No.61201432)Colleges and universities of Shandong Province science and technology plan projects(No.J16LE16)the Natural Science Foundation of Shandong Province(ZR2017BG016).
文摘The supply chain of perishable products is a combination of information organization,sharing and integration.The information modeling of supply chain is constructed to abstract key quality information including environment information,processing procedures and product quality assessments based on principle of quality safety factors and property of decay rate.The coloured Petri Net is applied for integrated description of independent information classification,aiming at risk identification and risk management framework.Well,according to the quality deterioration tendency,risk grades management and decision-making system are established.Practically,the circulation system of aquatic products is studied in this paper for full processing description.The simulation experiments are manipulated on environmental information,processing information and product quality information by the coloured Petri Net.Eventually,the conclusion turns out precisely as such that the coloured Petri Net conclusive for information classification and information transmission while integrated information management is available of efficient risk identification and decision-making system in supply chain of perishable products.Meanwhile,the validity of evaluating management and shelf-life estimation of perishable products are technically feasible.
