Fully probabilistic control for stochastic nonlinear control systems with input dependent noise

Robust controllers for nonlinear stochastic systems with functional uncertainties can be consistently designed using probabilistic control methods. In this paper a generalised probabilistic controller design for the minimisation of the Kullback-Leibler divergence between the actual joint probability density function (pdf) of the closed loop control system, and an ideal joint pdf is presented emphasising how the uncertainty can be systematically incorporated in the absence of reliable systems models. To achieve this objective all probabilistic models of the system are estimated from process data using mixture density networks (MDNs) where all the parameters of the estimated pdfs are taken to be state and control input dependent. Based on this dependency of the density parameters on the input values, explicit formulations to the construction of optimal generalised probabilistic controllers are obtained through the techniques of dynamic programming and adaptive critic methods. Using the proposed generalised probabilistic controller, the conditional joint pdfs can be made to follow the ideal ones. A simulation example is used to demonstrate the implementation of the algorithm and encouraging results are obtained.

Probabilistic control for uncertain systems

In this paper a new framework has been applied to the design of controllers which encompasses nonlinearity, hysteresis and arbitrary density functions of forward models and inverse controllers. Using mixture density networks, the probabilistic models of both the forward and inverse dynamics are estimated such that they are dependent on the state and the control input. The optimal control strategy is then derived which minimizes uncertainty of the closed loop system. In the absence of reliable plant models, the proposed control algorithm incorporates uncertainties in model parameters, observations, and latent processes. The local stability of the closed loop system has been established. The efficacy of the control algorithm is demonstrated on two nonlinear stochastic control examples with additive and multiplicative noise.

Fully probabilistic control design in an adaptive critic framework

Optimal stochastic controller pushes the closed-loop behavior as close as possible to the desired one. The fully probabilistic design (FPD) uses probabilistic description of the desired closed loop and minimizes Kullback-Leibler divergence of the closed-loop description to the desired one. Practical exploitation of the fully probabilistic design control theory continues to be hindered by the computational complexities involved in numerically solving the associated stochastic dynamic programming problem. In particular very hard multivariate integration and an approximate interpolation of the involved multivariate functions. This paper proposes a new fully probabilistic contro algorithm that uses the adaptive critic methods to circumvent the need for explicitly evaluating the optimal value function, thereby dramatically reducing computational requirements. This is a main contribution of this short paper.

A decision support system for supplier selection and order allocation in stochastic, multi-stakeholder and multi-criteria environments

Integrated supplier selection and order allocation is an important decision for both designing and operating supply chains. This decision is often influenced by the concerned stakeholders, suppliers, plant operators and customers in different tiers. As firms continue to seek competitive advantage through supply chain design and operations they aim to create optimized supply chains. This calls for on one hand consideration of multiple conflicting criteria and on the other hand consideration of uncertainties of demand and supply. Although there are studies on supplier selection using advanced mathematical models to cover a stochastic approach, multiple criteria decision making techniques and multiple stakeholder requirements separately, according to authors' knowledge there is no work that integrates these three aspects in a common framework. This paper proposes an integrated method for dealing with such problems using a combined Analytic Hierarchy Process-Quality Function Deployment (AHP-QFD) and chance constrained optimization algorithm approach that selects appropriate suppliers and allocates orders optimally between them. The effectiveness of the proposed decision support system has been demonstrated through application and validation in the bioenergy industry.

Current and future uses of IT in Europe and the Far East:achieving competitive advantage with 3PL

Current and future IT applications effecting supply chains in Europe and Pacific Asia are investigated. 3PL providers increasingly use IT systems for logistics, to enhance supply chain collaboration with business partners. Advanced systems are not always immediately profi table. Most companies already implement IT systems for processing transactions but motivations vary and barriers remain since 3PL providers incompletely understand clients' IT requirements. Long-term productivity gains require sophisticated IT systems to streamline cycles and improve supply chain visibility to facilitate, plan and make decisions. RFID and advanced integration systems, including Business Process Management, are probably the next trend in IT logistics systems. Copyright © 2012 Inderscience Enterprises Ltd.

Probabilistic DHP adaptive critic for nonlinear stochastic control systems

Following the recently developed algorithms for fully probabilistic control design for general dynamic stochastic systems (Herzallah & Káarnáy, 2011; Kárný, 1996), this paper presents the solution to the probabilistic dual heuristic programming (DHP) adaptive critic method (Herzallah & Káarnáy, 2011) and randomized control algorithm for stochastic nonlinear dynamical systems. The purpose of the randomized control input design is to make the joint probability density function of the closed loop system as close as possible to a predetermined ideal joint probability density function. This paper completes the previous work (Herzallah & Kárnáy, 2011; Kárný, 1996) by formulating and solving the fully probabilistic control design problem on the more general case of nonlinear stochastic discrete time systems. A simulated example is used to demonstrate the use of the algorithm and encouraging results have been obtained.

A simulation conceptual modelling procedure for SCM applications

Purpose – The purpose of this paper is to outline a seven-phase simulation conceptual modelling procedure that incorporates existing practice and embeds a process reference model (i.e. SCOR). Design/methodology/approach – An extensive review of the simulation and SCM literature identifies a set of requirements for a domain-specific conceptual modelling procedure. The associated design issues for each requirement are discussed and the utility of SCOR in the process of conceptual modelling is demonstrated using two development cases. Ten key concepts are synthesised and aligned to a general process for conceptual modelling. Further work is outlined to detail, refine and test the procedure with different process reference models in different industrial contexts. Findings - Simulation conceptual modelling is often regarded as the most important yet least understood aspect of a simulation project (Robinson, 2008a). Even today, there has been little research development into guidelines to aid in the creation of a conceptual model. Design issues are discussed for building an ‘effective’ conceptual model and the domain-specific requirements for modelling supply chains are addressed. The ten key concepts are incorporated to aid in describing the supply chain problem (i.e. components and relationships that need to be included in the model), model content (i.e. rules for determining the simplest model boundary and level of detail to implement the model) and model validation. Originality/value – Paper addresses Robinson (2008a) call for research in defining and developing new approaches for conceptual modelling and Manuj et al., (2009) discussion on improving the rigour of simulation studies in SCM. It is expected that more detailed guidelines will yield benefits to both expert (i.e. avert typical modelling failures) and novice modellers (i.e. guided practice; less reliance on hopeful intuition)

Non-stationary stochastic inventory lot-sizing with emission and service level constraints in a carbon cap-and-trade system

Firms worldwide are taking major initiatives to reduce the carbon footprint of their supply chains in response to the growing governmental and consumer pressures. In real life, these supply chains face stochastic and non-stationary demand but most of the studies on inventory lot-sizing problem with emission concerns consider deterministic demand. In this paper, we study the inventory lot-sizing problem under non-stationary stochastic demand condition with emission and cycle service level constraints considering carbon cap-and-trade regulatory mechanism. Using a mixed integer linear programming model, this paper aims to investigate the effects of emission parameters, product- and system-related features on the supply chain performance through extensive computational experiments to cover general type business settings and not a specific scenario. Results show that cycle service level and demand coefficient of variation have significant impacts on total cost and emission irrespective of level of demand variability while the impact of product's demand pattern is significant only at lower level of demand variability. Finally, results also show that increasing value of carbon price reduces total cost, total emission and total inventory and the scope of emission reduction by increasing carbon price is greater at higher levels of cycle service level and demand coefficient of variation. The analysis of results helps supply chain managers to take right decision in different demand and service level situations.

Is keiretsu really a source of competitive advantage for Japanese automotive suppliers?

Purpose - The purpose of this paper is to examine how firms create and sustain competitive advantage in the inter-firm business relationships from a supplier's perspective. It also investigates what factors affect their competitiveness and relationship between buyers and suppliers. Design/methodology/approach - This is an exploratory study on keiretsu partnerships composed of four main phases: analysis of theoretical perspectives, construction of a conceptual framework, interview of a CEO, and finally, a survey questionnaire with Japanese automotive suppliers. Findings - As a result, this paper classified these 11 companies into four supplier groups (affiliated or independent Tier 1 suppliers; affiliated or independent Tier 2 suppliers) and analysed their competitiveness developing the research propositions further. The benefits of affiliation under a keiretsu partnership are discussed, showing that there may be little benefit in being an affiliated Tier 1 supplier. Even more critical, the results show that independent Tier 2 supplier may be more competitive than affiliated tier ones. Originality/value - These intriguing results reveal an urgent need of investigating Japanese automotive supply chains from the suppliers' perspectives in the future research. This paper extended the literatures on competitive advantage and business relationships at both theory and managerial practice.

Technology in Parkinson's disease:challenges and opportunities

The miniaturization, sophistication, proliferation, and accessibility of technologies are enabling the capture of more and previously inaccessible phenomena in Parkinson's disease (PD). However, more information has not translated into a greater understanding of disease complexity to satisfy diagnostic and therapeutic needs. Challenges include noncompatible technology platforms, the need for wide-scale and long-term deployment of sensor technology (among vulnerable elderly patients in particular), and the gap between the "big data" acquired with sensitive measurement technologies and their limited clinical application. Major opportunities could be realized if new technologies are developed as part of open-source and/or open-hardware platforms that enable multichannel data capture sensitive to the broad range of motor and nonmotor problems that characterize PD and are adaptable into self-adjusting, individualized treatment delivery systems. The International Parkinson and Movement Disorders Society Task Force on Technology is entrusted to convene engineers, clinicians, researchers, and patients to promote the development of integrated measurement and closed-loop therapeutic systems with high patient adherence that also serve to (1) encourage the adoption of clinico-pathophysiologic phenotyping and early detection of critical disease milestones, (2) enhance the tailoring of symptomatic therapy, (3) improve subgroup targeting of patients for future testing of disease-modifying treatments, and (4) identify objective biomarkers to improve the longitudinal tracking of impairments in clinical care and research. This article summarizes the work carried out by the task force toward identifying challenges and opportunities in the development of technologies with potential for improving the clinical management and the quality of life of individuals with PD. © 2016 International Parkinson and Movement Disorder Society.

Revisiting the lean agile paradigm:an empirical study in the aerospace industry

Much has been written about the potential impact of Lean Agile paradigm on firm's supply chain performance. However, most of the existing studies mainly pointed out Lean is for cost reduction, whereas Agility is for attaining flexibility. There are little empirical studies in literature that examined how Lean Agile paradigm impacts on supply chain performance. This paper aims to address this gap by studying the influence of Lean and Agility paradigms on a single commodity supply chain delivery performance in the aerospace industry. Data was collected from four separate 'Rigid pipes' supply chains to study how manufacturing alignment impacts on the delivery performance. Implications of the study to practitioners and academia are discussed and future research outlined.

A Conceptual Foresight Model to Investigate the Adoption of Radio Frequency Identification Technology in the English National Health Service

Radio Frequency Identification Technology (RFID) adoption in healthcare settings has the potential to reduce errors, improve patient safety, streamline operational processes and enable the sharing of information throughout supply chains. RFID adoption in the English NHS is limited to isolated pilot studies. Firstly, this study investigates the drivers and inhibitors to RFID adoption in the English NHS from the perspective of the GS1 Healthcare User Group (HUG) tasked with coordinating adoption across private and public sectors. Secondly a conceptual model has been developed and deployed, combining two of foresight’s most popular methods; scenario planning and technology roadmapping. The model addresses the weaknesses of each foresight technique as well as capitalizing on their individual, inherent strengths. Semi structured interviews, scenario planning workshops and a technology roadmapping exercise were conducted with the members of the HUG over an 18-month period. An action research mode of enquiry was utilized with a thematic analysis approach for the identification and discussion of the drivers and inhibitors of RFID adoption. The results of the conceptual model are analysed in comparison to other similar models. There are implications for managers responsible for RFID adoption in both the NHS and its commercial partners, and for foresight practitioners. Managers can leverage the insights gained from identifying the drivers and inhibitors to RFID adoption by making efforts to influence the removal of inhibitors and supporting the continuation of the drivers. The academic contribution of this aspect of the thesis is in the field of RFID adoption in healthcare settings. Drivers and inhibitors to RFID adoption in the English NHS are compared to those found in other settings. The implication for technology foresight practitioners is a proof of concept of a model combining scenario planning and technology roadmapping using a novel process. The academic contribution to the field of technology foresight is the conceptual development of foresight model that combines two popular techniques and then a deployment of the conceptual foresight model in a healthcare setting exploring the future of RFID technology.

Environmental Management Accounting - Estimating the Benefit Side

The presentation focuses on estimating benefits of environmental projects and achievements like image improvement, gaining an environmental award, profit from environmentally benign products, risk reduction benefits, etc. The paper integrates the results and experience gained in three different fields: EMA, evaluation of natural resources and working as a consultant

Az ellátási lánc tudatos folyamat- és kockázatmenedzsmentjének hatás a teljesítményre

Az ellátási lánc menedzsmentje jól ismert és régóta tanulmányozott területe a menedzsment tudománynak. Jelen tanulmány célja, hogy egy olyan modell létezését igazolja, amely szerint egy ellátási láncban az információ menedzsmentje, az anyagi áramlások koordinációja és költségek és a teljesítmény kontrollja elengedhetetlen a teljes lánc magas szintű teljesítményéhez, és ezt a kockázatmenedzsment eszközök alkalmazásával tovább lehet növelni. Az ellátási lánc menedzsment eszközök támogatják a partnerek közötti információ megosztást (pl. EDI), az anyagi áramlások kisimítását (pl. folyamatos feltöltés, cross-docking). A költség és teljesítmény menedzsment eszközök alkalmazásának célja pedig hogy feltárják, hogy a költségek és hasznok miként oszlanak meg, merülnek fel az egyes ellátási lánc szereplők között. Ezeket az eszközöket akár vállalati, akár ellátási lánc szinten alkalmazzák, a végső cél a teljes ellátási lánc teljesítményének a növelése. Az ellátási lánc teljesítményét úgy határozzuk meg, mint az érték, amely a végső vevő számára keletkezett valamint a profit, amit az ellátási lánc partnerek realizáltak. Habár a vállalatok és az ellátási láncok különféle eszközöket alkalmazhatnak, hogy menedzseljék különböző folyamataikat, az a mód, ahogy szembenéznek a felmerülő kockázatokkal – fakadjanak akár a rendszerből magából, vagy a környezetből - és kezelik azokat, alapvető hatással bír a végső teljesítményre, így a versenyképességre is. A bemutatott kutatási modellel azt a kapcsolatot szeretnénk igazolni, amely feltevéseink szerint az ellátási láncban alkalmazott, a különféle alapfolyamatok menedzsmentjére valamint a kockázat menedzsmentjére használt eszközök és a realizált teljesítmény között van. _______ Supply chain management is a well-known and intensely studied field of management science. Our aim is to construct and test a model which summarises that besides the tools adapted to manage information flow, materials flow and costs and performance in supply chains to achieve high overall performance, managing risks is also inevitable. Supply chain management tools are to improve the efficiency of information sharing between supply chain participants (e.g. EDI) and to smooth materials flow carried out by the parties in collaboration (e.g. continuous replenishment, cross-docking). Cost management and performance assessment tools aim to explore the costs and profit realised by the cooperating companies as well as the entire supply chain. All the tools adapted either at a company or on supply chain level, strive to enhance the overall performance of the supply chain. The performance of a supply chain can be assessed by the value created for the end consumer and by the profit the partners realise. However, companies and supply chains adopt tools to manage the different flows, the way they face and handle risks coming either from the system or from the surrounding environment have a key influence on the performance achieved and consequently on competitiveness, too. When constructing the research model we try to find and verify the linkage between the tools supply chains use for coordination and for managing risks and the performance achieved.

A methodology to select an enterprise resource planning system for a small or medium sized enterprise

Enterprise Resource Planning (ERP) systems are software programs designed to integrate the functional requirements, and operational information needs of a business. Pressures of competition and entry standards for participation in major manufacturing supply chains are creating greater demand for small business ERP systems. The proliferation of new offerings of ERP systems introduces complexity to the selection process to identify the right ERP business software for a small and medium-sized enterprise (SME). The selection of an ERP system is a process in which a faulty conclusion poses a significant risk of failure to SME’s. The literature reveals that there are still very high failure rates in ERP implementation, and that faulty selection processes contribute to this failure rate. However, the literature is devoid of a systematic methodology for the selection process for an ERP system by SME’s. This study provides a methodological approach to selecting the right ERP system for a small or medium-sized enterprise. The study employs Thomann’s meta-methodology for methodology development; a survey of SME’s is conducted to inform the development of the methodology, and a case study is employed to test, and revise the new methodology. The study shows that a rigorously developed, effective methodology that includes benchmarking experiences has been developed and successfully employed. It is verified that the methodology may be applied to the domain of users it was developed to serve, and that the test results are validated by expert users and stakeholders. Future research should investigate in greater detail the application of meta-methodologies to supplier selection and evaluation processes for services and software; additional research into the purchasing practices of small firms is clearly needed.^