Managing perishability in production-distribution planning: a discussion and review

Managing perishability may represent a remarkable problem in supply chain management of a varied set of industries. In fact, perishability can influence, for example, productivity or customer service and it may happen to occur in one or more processes throughout the supply chain. In this paper a review on planning models that handle perishability issues in production and distribution is conducted. The contribution of this paper is three-fold. First, a new framework for classifying perishability models based on multiple process features is presented. Second, it draws the community attention to the importance of managing perishability in many different industries’ supply chains by showing its relevance and by reviewing the literature related to production and distribution planning. Finally, it points towards research opportunities so far not addressed by the research community in this challenging field.     

Agent-Oriented Supply-Chain Management

The supply chain is a worldwide network of suppliers, factories, warehouses, distribution centers, and retailers through which raw materials are acquired, transformed, and delivered to customers. In recent years, a new software architecture for managing the supply chain at the tactical and operational levels has emerged. It views the supply chain as composed of a set of intelligent software agents, each responsible for one or more activities in the supply chain and each interacting with other agents in the planning and execution of their responsibilities. This paper investigates issues and presents solutions for the construction of such an agent-oriented software architecture. The approach relies on the use of an agent building shell, providing generic, reusable, and guaranteed components and services for communicative-act-based communication, conversational coordination, role-based organization modeling, and others. Using these components, we show two nontrivial agent-based supply-chain architectures able to support complex cooperative work and the management of perturbation caused by stochastic events in the supply chain.     

A two-stage sequential planning scheme for integrated operations planning and scheduling system using MILP: the case of an engine assembler

This paper presents an operations planning scheme based on mathematical programming models (specifically, Mixed-Integer Linear Programming (MILP) models) integrated into a web-enabled Advanced Planning and Scheduling System (APS), developed for and implemented in an engine assembler that supplies the car industry. One objective of this paper is to provide empirical insights into some operations planning characteristics in the automotive industry. The other main objective is to show MILP models and their use to create plans that enable the coordination of different planning levels (mid-term and short-term) and planning domains (procurement, production and distribution). The APS fulfills the requirements of an engine assembler in the automotive sector (namely lean-type constraints and objectives). The system is based on two MILP models, which have been purposely developed together along with their relations. The models presented herein provide a solution that considers supply chain objectives and constraints, and are integrated by means of data and constraints which have proven sufficient to fulfill users?? and stakeholders?? requirements. This case study presents the models?? most relevant aspects and their implementation.     

An industry survey of implementation strategies for clinical supply chain management of cell and gene therapies

Background aimsThe novelty of cell and gene therapies (CGTs) has introduced unique supply chain challenges and considerations not seen by chemically synthesized (small-molecule) drugs. These complexities increase during the clinical phases, where drug safety and efficacy milestones are still underdeveloped. For example, for autologous therapies such as chimeric antigen receptor T-cell therapies, in which the treatment is developed from the patient's own cells, supply chain management plays an integral role in chemistry, manufacturing and control processes. Supply chain management requires proactive planning because of the strict cold chain requirements and time sensitivity of CGTs. This research examines strategies and responses to challenges experienced by industry stakeholders (e.g., sponsors and manufacturers) during the implementation phases of clinical supply chain management. This research further evaluates the adequacy of the current regulatory framework for distribution and supply chain management of CGTs in the US.MethodsA survey methodology was used to query subject matter experts from the biopharmaceutical industry who were familiar with the clinical supply management of CGTs in the US. The survey instrument was developed using an implementation framework and disseminated electronically to mid- and senior-level subject matter experts who had experience with clinical trials, supply chain management and CGTs.ResultsA total of 128 respondents accessed the survey, and 105 respondents answered at least one question. Seventy-five respondents completed the survey. Results showed that a lack of harmonization in regulations across the supply chain, limited resources, challenges with vendor management, high costs and complexities in the supply chain due to product specificity and customization proved to be impediments for the industry. In addition, the coronavirus disease 2019 pandemic had a significant impact on supply chain implementation. The results revealed that less than half of the respondents had business continuity plans in place. These challenges increased for smaller and mid-size organizations. Thirty percent of small and mid-size organizations were less prepared to scale up than larger companies.ConclusionsSuggestions from industry stakeholders were to adopt and enforce Good Distribution Practices in the US (81%), pre-plan distribution strategies with internal and external stakeholders along the supply chain and develop agile systems and robust processes end to end. Hurdles in scaling up and scaling out from the clinical to commercial phases for time- and temperature-sensitive CGT products make it difficult to predict the supply chain's long-term feasibility. Although there are initiatives to improve these impediments, such as improving industry partnerships and creating global CGT transportation standards, there are still regulatory knowledge gaps present for CGTs. Therefore, it is essential to establish a baseline and foundation for CGT supply chains extending beyond the loading dock.     

A New Tradeoff Model for Fuzzy Supply Chain Network Design and Optimization

This article proposes a novel mixed integer linear programming model for solving a fuzzy supply chain network (SCN) design problem. This problem includes fuzzy parameters, choosing suppliers according to their quality of raw materials, and the supplier's engagement contracts. There is a tradeoff between raw material quality, and its purchasing and reprocessing costs. If a decision-maker (DM) wishes to work with a supplier that supplies a low-quality raw material, this raw material may be in need of reprocessing. To avoid the reprocessing costs, a supplier that provides a high-quality raw material can be chosen, but in this case the DM faces a high purchasing cost. An integrated fuzzy SCN system that consists of multiple suppliers, manufacturers, distribution centers, and retailers is considered in order to address problems under the aforementioned tradeoffs. Finally, concluding remarks and suggestions for future work are presented.     

Collaborative fractal-based supply chain management based on a trust model for the automotive industry

In the supply chain of the automotive industry, where the procurement ratio of parts from partners is very high, the trustworthiness of partners should be considered during supply chain optimization. In this paper, to deal with the trust issue related to collaboration and reduce the computational load in production planning, we develop a collaborative fractal-based supply chain management framework for the automotive industry. In our framework, the relationships between the participants of a supply chain are modeled as a fractal. Each fractal has a goal model and generates a production plan of its participants based on the goal model. The goal model of each fractal is developed from an operational perspective to consider the trust value of participants during production planning. A fuzzy trust evaluation model is used to evaluate the trust value in terms of numerical value. To validate the developed framework in the automotive industry, simulations are conducted. The results of the simulations indicate that our framework can be useful in generating precise production plans.     

Operational flexibility quantification in a make-to-order assembly system

Manufacturing flexibility is becoming a fundamental production objective, along with cost, quality, and delivery time. Current production systems face quick changes in market conditions and they need to adapt in this environment. The supply chain and industrial globalization give an important role for assembly systems. Placed at the end of the value chain, assembly systems must face those quick changes successfully to reach the expected performance. The key performance indicators are normally based on cost, quality, and delivery time objectives. Reducing costs and improving quality are almost universal goals. Delivery time is typically determined by customer demand in the supply chain, planning from make-to-stock to make-to-order, and aspiring to reach a just-in-time manufacturing system. In this context, flexibility could be the differential advantage to tackle uncertainty. Closely related to the rest of production objectives and the overall performance of the system, flexibility must be integrated in the system for successful decision-making in operations. This work presents this approach of flexibility. A brief review of flexibility concepts and measurements in the literature precedes an introduction to flexibility, defined based on the function of utility. This function represents the expectations of system performance. This approach allows the formulation of the taxonomy of operational flexibility in agreement with the classical types identified in former works. Next, an integer model is programmed to simulate the basic behavior of task planning in a make-to-order assembly system. This first application illustrates flexibility quantification based on utility evolution. The use of common industrial parameters to quantify operational flexibility will finally facilitate an integrated interpretation of system performance trends.     

Multi-objective fuzzy design of closed-loop supply chain network considering risks and environmental impact

Due to governmental, environmental, and economic concerns, the closed-loop supply chain network has attracted the attention of researchers. In this article, a multiproduct, multi-echelon, and multi-objective closed-loop supply chain network model in a fuzzy environment is proposed. The forward supply chain network includes raw material suppliers, virgin material suppliers, plants, distribution centers, and customer zones, while the reverse supply chain network is composed of customer zones, collection centers, refurbishing centers, dismantling centers, and decomposition centers. The objectives of this model are to minimize the total cost, waste, carbon dioxide, and risks. In order to solve the proposed model, a fuzzy multi-objective optimization method is used. A numerical example validates and verifies the practicability of the fuzzy model and solution method, and demonstrates the proposed model and method can be applied to solve real world problems.     

The maggot therapy supply chain: a review of the literature and practice

Maggot therapy (MT) is the clinical application of living fly larvae for the treatment of non-healing wounds and wounds that require debridement. This systematized and expanded literature review is the first study to investigate MT through the conceptual and disciplinary framework of supply chain management. The review of 491 selected academic papers was expanded to include the grey literature and online information resources to construct a first-pass theory of the medicinal maggot supply chain. It shows that the literature to date has focused on isolated discussions of echelon-specific issues such as diet improvement and sterilization protocols in the production echelon, and the relative effectiveness of medicinal maggot application methods in the treatment echelon. There is little knowledge in the public domain regarding the transport and distribution of medicinal maggots, but existing supply chains for vaccines, blood and pathology specimens may provide learning and supply chain integration opportunities. Maggot therapy knowledge across the treatment echelon is generally substantive but there is still insufficient knowledge regarding patients' and health care providers' attitudes toward the therapy, and their experiences of receiving and administering MT. Moreover, there is no research concerned with the humane disposal of medicinal flies during production and after treatment.     

Review of research on closed loop supply chain management in the process industry

Closed loop supply chain (CLSC) management is a major enabler for sustainability in value creating networks. This contribution aims to describe and analyze the main characteristics of CLSC planning in the process industry and the related publications, in order to determine the evolution and gaps of this current research over time and improve our understanding of this issue. We built up a database with the articles on CLSC in different sectors of the process industry and identified the most relevant journals within this field. Furthermore, we derive and identify the requirements for CLSC considerations in the process industry for verifying whether these requirements are met in the literature so far. In addition, we have explored the topic, the methodology and the techniques of analysis, as well as other relevant aspects of the research in this field. We mainly focus on general and specific quantitative approaches, observing what has been done and how, where and by whom it has been carried out. The result is an extensive review of the research work itself and their limitations having an influence on CLSC concepts for the process industry. We conclude with some suggestions to those who begin to research on this apparently disregarded topic.     

Financial Risk Assessment and Optimal Planning of Biofuels Supply Chains under Uncertainty

Biofuels provide an attractive alternative for satisfying energy demands in a more sustainable way than fossil fuels. To establish a biorefinery, an optimal plan must be implemented for the entire associated supply chain, covering such aspects as selection of feedstocks, location, and capacity of biorefineries, selection of processing technologies, production amounts and transportation flows. In this context, there are several parameters, including the availability of biomass, product demand, and product prices, which are difficult to predict because they might change drastically over the different seasons of the year as well as across years. To address this challenge, this work presents a mathematical programming model for the optimal planning of a distributed system of biorefineries that considers explicitly the uncertainty associated with the supply chain operation as well as the associated risk. The potential of the proposed approach is demonstrated through its application to the production of biofuels in Mexico, considering multiple raw materials and products.     

LabVelocity: online tools for life science products, protocols, technical information, MEDLINE searches, and laboratory calculations.

As the pace of life science discovery increases, so do the demands on researchers. To remain competitive in the life science industry, researchers must use every tool at their disposal to keep up with new products, protocols, news, and literature in their field. While there are now myriad Web sites that assist researchers with this problem, many suffer from confusing user interfaces, poorly designed search engines, and a narrow information focus. Here, we present LabVelocity, a user-friendly Web site that provides a free multidisciplinary information-gathering service for the life science research community. Using LabVelocity, a researcher can quickly find the products, protocols, technical references, news, MEDLINE abstracts, and interactive software tools necessary for an experiment. This aggregation of information can streamline experimental planning and is especially useful when researchers want to set up a new laboratory or to venture outside their field of expertise.     

Intelligent management of supply chain logistics based on 5g LoT

With the rapid development of science and technology and the integration of the global economy, competition in the global market has become increasingly fierce, and competition between enterprises has gradually become competition between supply chains. The application of Internet technology to the agricultural industry chain has a wide potential for development, and the LoT and the big data have become an important pillar of the development of smart agriculture. The implementation of Internet technology improves the degree of visibility and transparency of the agricultural supply chain, reduces supply chain uncertainty and improves the smart management of the supply chain. Research, development and implementation of technology 5g LoT brings new development opportunities for traditional supply chain management. In order to understand changes in the production and life of people under the 5g Internet environment of things, this document uses case analysis and bibliographic analysis methods for the collection of documents from the CNKI, Wanfang database, SSCI and other databases and analyses different fields of life using GIS spatial analysis technology. The results of the survey show that, in the case of the use of the 5g LoT, the supply chain may provide more information on the development of an intelligent supply chain, the smart level of chain efficiency has significantly improved, and the percentage is approximately 25%. This article takes as an example the supply of cars, with the help of the LoT system, the accuracy of delivery and the speed of logistics transport have improved significantly. In the smart model, the coefficient can reach 0813, which shows that smart management of the supply chain fewer than 5g LoT can play a major role.

     

Distribution and Availability of Essential Tuberculosis Diagnostic Items in Amhara Region,Ethiopia

Adequate supplies of tuberculosis laboratory reagents and consumables are necessary for tuberculosis diagnosis and monitoring of treatment response. This study assessed the distribution and stock levels of laboratory commodities used in tuberculosis control in health centers of Amhara region, Ethiopia. A cross-sectional study was conducted in 82 health centers, among 801, providing sputum microscopy services. Stock levels were calculated, and distribution of reagents and consumables assessed. Thirty three (40.2%) health centers were under stocked for at least one of the key items for tuberculosis diagnosis at the time of visit. Fifteen (18.3%) health centers had no stocks of at least one of the key items (methylene blue (11%), carbol fuchsin (11%), acid alcohol (8.5%) and sputum cups (3.7%)). Of the 82 health centers, 77 (93.9%) did not fulfill the criteria for effective distribution of tuberculosis laboratory reagents and consumables. There were many health centers that had no or only low stocks of key tuberculosis laboratory reagents and consumables as a result of ineffective distribution system. It is necessary to strengthen supply chain management to ensure uninterrupted TB diagnostic service.     

Structure of urban movements: polycentric activity and entangled hierarchical flows

The spatial arrangement of urban hubs and centers and how individuals interact with these centers is a crucial problem with many applications ranging from urban planning to epidemiology. We utilize here in an unprecedented manner the large scale, real-time 'Oyster' card database of individual person movements in the London subway to reveal the structure and organization of the city. We show that patterns of intraurban movement are strongly heterogeneous in terms of volume, but not in terms of distance travelled, and that there is a polycentric structure composed of large flows organized around a limited number of activity centers. For smaller flows, the pattern of connections becomes richer and more complex and is not strictly hierarchical since it mixes different levels consisting of different orders of magnitude. This new understanding can shed light on the impact of new urban projects on the evolution of the polycentric configuration of a city and the dense structure of its centers and it provides an initial approach to modeling flows in an urban system.     

When do conservation planning methods deliver? Quantifying the consequences of uncertainty

The rapid global loss of biodiversity has led to a proliferation of systematic conservation planning methods. In spite of their utility and mathematical sophistication, these methods only provide approximate solutions to real-world problems where there is uncertainty and temporal change. The consequences of errors in these solutions are seldom characterized or addressed. We propose a conceptual structure for exploring the consequences of input uncertainty and oversimplified approximations to real-world processes for any conservation planning tool or strategy. We then present a computational framework based on this structure to quantitatively model species representation and persistence outcomes across a range of uncertainties. These include factors such as land costs, landscape structure, species composition and distribution, and temporal changes in habitat. We demonstrate the utility of the framework using several reserve selection methods including simple rules of thumb and more sophisticated tools such as Marxan and Zonation. We present new results showing how outcomes can be strongly affected by variation in problem characteristics that are seldom compared across multiple studies. These characteristics include number of species prioritized, distribution of species richness and rarity, and uncertainties in the amount and quality of habitat patches. We also demonstrate how the framework allows comparisons between conservation planning strategies and their response to error under a range of conditions. Using the approach presented here will improve conservation outcomes and resource allocation by making it easier to predict and quantify the consequences of many different uncertainties and assumptions simultaneously. Our results show that without more rigorously generalizable results, it is very difficult to predict the amount of error in any conservation plan. These results imply the need for standard practice to include evaluating the effects of multiple real-world complications on the behavior of any conservation planning method.     

Function- and agonist-specific Ca2+ signalling: the requirement for and mechanism of spatial and temporal complexity in Ca2+ signals.

Calcium signals have been implicated in the regulation of many diverse cellular processes. The problem of how information from extracellular signals is delivered with specificity and fidelity using fluctuations in cytosolic Ca2+ concentration remains unresolved. The capacity of cells to generate Ca2+ signals of sufficient spatial and temporal complexity is the primary constraint on their ability to effectively encode information through Ca2+. Over the past decade, a large body of literature has dealt with some basic features of Ca2+-handling in cells, as well as the multiplicity and functional diversity of intracellular Ca2+ stores and extracellular Ca2+ influx pathways. In principle, physiologists now have the necessary information to attack the problem of function- and agonist-specificity in Ca2+ signal transduction. This review explores the data indicating that Ca2+ release from diverse sources, including many types of intracellular stores, generates Ca2+ signals with sufficient complexity to regulate the vast number of cellular functions that have been reported as Ca2+-dependent. Some examples where such complexity may relate to neuroendocrine regulation of hormone secretion/synthesis are discussed. We show that the functional and spatial heterogeneity of Ca2+ stores generates Ca2+ signals with sufficient spatiotemporal complexity to simultaneously control multiple Ca2+-dependent cellular functions in neuroendocrine systems.     

基于持续高产的近海渔业双寡头捕捞策略

海洋鱼类是人类一种重要的生活物质资料,当代人在进行渔业捕捞满足自身生活需求时,应合理确定捕捞努力量以实现渔业资源的可持续利用,不危及后代人的需求,假定存在两个捕捞主体,分别就Cournot模型和Stackelbeerg模型分析了两个主体为了自身获得最大持续产量而投入的捕捞努力量,研究表明,与只有一个捕捞主体相比,当存在两个捕捞主体时,每个捕捞主体都将投入更多的捕捞努力量,但最大持续产量不随之增加,甚至还会减少,产生这种后果的原因在于每个主体只考虑自己投入的捕捞 努力量对自己产出量的影响,而不考虑对对方或社会产生的负面影响,对渔业捕捞进行全面规划,综合管理是消除这种后果所必要的。     

基于文献计量的绿色基础设施水生态系统服务供需评价研究进展

作为国家的自然生命支持系统,区域、城市和社区尺度的绿色基础设施可提供多种水生态系统服务。然而,服务在传递过程中存在空间错位与时间滞后效应。绿色基础设施水生态系统服务供需评价能够识别供需时空异质特征,促进服务供给与需求的均衡。研究利用Citespace对国内外相关研究展开分析,阐明了绿色基础设施水生态系统服务的供需内涵,对供需评价内容、评价方法与均衡分析方法进行了综述。研究发现：(1)融合生态系统服务供需评价与绿色基础设施规划设计的研究有了初步进展,但针对绿色基础设施水生态系统服务的系统性研究并不多见。(2)供给评价研究丰富,测度指标多依赖客观的生物物理数据;需求评价热度上升,测度指标多基于消费、偏好、感知和社会经济价值;测度单元有行政单元、流域/生境等环境单元与土地利用单元等。(3)评价方法有生态模型法、公众参与法、价值评价法与经验统计模型法,生态模型法逐渐普及,提出了评价方法的选用与关键参数确定的原则。(4)供需均衡研究多聚焦数量、空间的静态均衡研究,动态均衡研究有待进一步探索。基于当前研究动态,未来应重点关注多尺度下供需评价指标体系构建,探索供需评价的集成方法,提高供需评价精度,加...     

Distribution and diversity of Arctic-Alpine species in the Balkans

The distributions of 77 Arctic-Alpine species in the Balkans are mapped and the centers of their richness and diversity presented. Within the Dinaric Alps these are Mts Vranica, Durmitor, and Prokletije; in the Scardo-Pindhic mountains, ?arplanina–Rudoka–Korab form a continuous chain; in the Rhodope-Rila mountain system there are Mts Vito?a, Rila, and Pirin; while in the Balkan mountain system there are the West and Central part of Stara planina. A comparison of floristic richness and distribution of Arctic-Alpine flora in relation to altitude, geographical location, and geological substrate is made. Correlations between floristic richness and geographical distance of the Balkan mountains from the two main centers of Arctic-Alpine flora in Central Europe are also provided.