An empirical study of green supply chain management practices amongst UK manufacturers

Purpose: The purpose of this paper is to examine the extent and nature of greening the supply chain (SC) in the UK manufacturing sector; and the factors that influence the breadth and depth of this activity.

Design/methodology/approach: Based on the findings from a sample of manufacturing organisations drawn from the membership of The Chartered Institute for Purchasing and Supply. Data are collected using a questionnaire, piloted and pre-tested before distribution with responses from 60 manufacturing companies.

Findings: On average manufacturers perceive the greatest pressure to improve environmental performance through legislation and internal drivers (IDs). The least influential pressures are related to societal drivers and SC pressures from individual customers. Green supply chain management (GSCM) practices amongst this “average” group of UK manufacturing organisations are focusing on internal, higher risk, descriptive activities, rather than proactive, external engagement processes. Environmental attitude (EA) is a key predictor of GSCM activity and those organisations that have a progressive attitude are also operationally very active. EA shows some relationship to legislative drivers but other factors are also influential. Operational activity may also be moderated by organisational contingencies such as risk, size, and nationality.

Research limitations/implications: The main limitation to this paper is the relatively small manufacturing sample.

Practical implications: This paper presents a series of constructs that identify GSCM operational activities companies to benchmark themselves against. It suggests which factors are driving these operational changes and how industry contingencies may be influential.

Originality/value: This paper explores what is driving environmental behaviour amongst an “average” sample of manufacturers, what specific management practices take place and the relationships between them.

Keywords: Manufacturing industries, Environmental management, Supply chain management, Sustainable development, United Kingdom
Paper type: Research paper

Hybridization of a class of "second order" models of traffic flow

Despite the simultaneous progress of traffic modelling both on the macroscopic and microscopic front, recent works [E. Bourrel, J.B. Lessort, Mixing micro and macro representation of traffic flow: a hybrid model based on the LWR theory, Transport. Res. Rec. 1852 (2003) 193–200; D. Helbing, M. Treiber, Critical discussion of “synchronized flow”, Coop. Transport. Dyn. 1 (2002) 2.1–2.24; A. Hennecke, M. Treiber, D. Helbing, Macroscopic simulations of open systems and micro–macro link, in: D. Helbing, H.J. Herrmann, M. Schreckenberg, D.E. Wolf (Eds.), Traffic and Granular Flow ’99, Springer, Berlin, 2000, pp. 383–388] highlighted that one of the most promising way to simulate efficiently traffic flow on large road networks is a clever combination of both traffic representations: the hybrid modelling. Our focus in this paper is to propose two hybrid models for which the macroscopic (resp. mesoscopic) part is based on a class of second order model [A. Aw, M. Rascle, Resurection of second order models of traffic flow?, SIAM J. Appl. Math. 60 (2000) 916–938] whereas the microscopic part is a Follow-the Leader type model [D.C. Gazis, R. Herman, R.W. Rothery, Nonlinear follow-the-leader models of traffic flow, Oper. Res. 9 (1961) 545–567; R. Herman, I. Prigogine, Kinetic Theory of Vehicular Traffic, American Elsevier, New York, 1971]. For the first hybrid model, we define precisely the translation of boundary conditions at interfaces and for the second one we explain the synchronization processes. Furthermore, through some numerical simulations we show that the waves propagation is not disturbed and the mass is accurately conserved when passing from one traffic representation to another.

Confined Site Construction: A qualitative investigation of critical issues affecting management of Health and Safety

The construction industry is inherently risky, with a significant number of accidents and disasters occurring, particularly on confined construction sites. This research investigates and identifies the various issues affecting successful management of health and safety in confined construction sites. The rationale is that identifying the issues would assist the management of health and safety particularly in inner city centres which are mostly confined sites. Using empiricism epistemology, the methodology was based on qualitative research approach by means of multiple case studies in three different geographical locations of Ireland, UK and USA. Data on each case study were collected through individual interviews and focus group discussion with project participants. The findings suggest that three core issues are the underlying factors affecting management of health and safety on confined construction sites. It include, (i) lack of space, (ii) problem of co-ordination and management of site personnel, and (iii) overcrowding of workplace. The implication of this is that project teams and their organisations should see project processes from a holistic point of view, as a unified single system, where quick intervention in solving a particular issue should be the norm, so as not to adversely affect interrelated sequence of events in project operations. Proactive strategies should be devised to mitigate these issues and may include detail project programming, space management, effective constructability review and efficient co-ordination of personnel, plant and materials among others. The value of this research is to aid management and operation of brownfield sites by identifying issues impacting on health and safety management in project process.

Management of long-term sickness absence: a systematic realist review

Purpose
The increasing impact and costs of long term sickness absence have been well documented. However, the diversity and complexity of interventions and of the contexts in which these take place makes a traditional review problematic. Therefore, we undertook a systematic realist review to identify the dominant programme theories underlying best practice, to assess the evidence for these theories, and to throw light on important enabling or disabling contextual factors.

Method
A search of the scholarly literature from 1950 to 2011 identified 5,576 articles, of which 269 formed the basis of the review.

Results
We found that the dominant programme theories in relation to effective management related to: early intervention or referral by employers; having proactive organisational procedures; good communication and cooperation between stakeholders; and workplace-based occupational rehabilitation. Significant contextual factors were identified as the level of support for interventions from top management, the size and structure of the organisation, the level of financial and organisational investment in the management of long-term sickness absence, and the quality of relationships between managers and staff.

Conclusions
Consequently, those with responsibility for managing absence should bear in mind the contextual factors that are likely to have an impact on interventions, and do what they can to ensure stakeholders have at least a mutual understanding (if not a common purpose) in relation to their perceptions of interventions, goals, culture and practice in the management of long term sickness absence.

Critical factors affecting management of site operatives and personal in confined construction site

The aim of this paper is to identify and classify the numerous managerial issues encountered in the management of personnel in confined site construction. For the purpose of this research, a confined construction site is defined as a site where permanent works fit the site footprint, extending to levels above and/or below ground level, leaving spatial restrictions for other operations (e.g. plant and material movements, materials storage and temporary accommodation etc.) and require effective resource co-ordination beyond normal on-site management input. A literature review and analysis, case studies incorporating interviews and focus groups along with a questionnaire survey were used in order to gain a comprehensive insight into the issues in the management of personnel in a confined construction site environment. The following are the top five leading issues highlighted in the management of personnel in confined site construction; (1) Accidents due to an untidy site, (2) One contractor holding up another because of the lack of space, (3) A risk to personnel because of vehicular traffic on-site, (4) Difficult to facilitate several contractors at one work location, and (5) Numerous personnel working within the one space. In today’s modern environment, spatial restrictions are quickly becoming the norm in the industry. Therefore, the management of personnel on-site becomes progressively more difficult with the decrease in available space on-site. Where such environments exist, acknowledging the numerous issues highlighted above, aids site management in the supervision and co-ordination of personnel on-site, thus reducing accidents, increasing productivity and increase profit margins, in spatially restricted environments. As on-site management professionals successfully identify, acknowledge and counteract the numerous issues illustrated, the successful management of personnel on a confined construction site is achievable. By identifying the numerous issues, on-site management can proactively mitigate such issues through adopting counteractive measures and through successful identification of the traits identified.

Strategies for Effective Management of Health and Safety in Confined Site Construction

The overall aim of this research is to identify and catalogue the numerous managerial strategies for effective management of health and safety on a confined, urban, construction site. A mixed methods methodology was adopted using interviews and focus group discussions on three selected case studies of confined construction sites. In addition to these, a questionnaire survey was used based on the findings from the interviews and the focus group discussions. The top five key strategies include (1) Employ safe system of work plans to mitigate personnel health and safety issues; (2) Inform personnel, before starting on-site, of the potential issues using site inductions; (3) Effective communication among site personnel; (4) Draft and implement an effective design site layout prior to starting on-site; and (5) Use of banksman (traffic co-ordinator) to segregate personnel from vehicular traffic. The construction sector is one of the leading industries in accident causation and with the continued development and regeneration of our urban centres, confined site construction is quickly becoming the norm - an environment which only fuels accident creation within the construction sector. This research aids on-site management that requires direction and assistance in the identification and implementation of key strategies for the management of health and safety, particularly in confined construction site environments.

Development of Device Identity using WIFI Layer 2 Management Frames for Combating Rogue APs

The susceptibility of WiFi networks to Rogue Access Point attacks derives from the lack of identity for 802.11 devices. The most common means of detecting these attacks in current research is through tracking the credentials or the location of unauthorised and possibly malicious APs. In this paper, the authors outline a method of distinguishing WiFi Access Points using 802.11 MAC layer management frame traffic profiles. This system does not require location estimation or credential tracking techniques as used in current research techniques, which are known to be inaccurate. These characteristic management traffic profiles are shown to be unique for each device, tantamount to a MAC identity. The application of this technique to solving Rogue AP attacks under the constraints of an open access, public WiFi environment is discussed with the conclusion that the identity is practically very difficult to forge

Adaptive Measurement-Based Policy-Driven QoS Management with Fuzzy-Rule-based Resource Allocation

Fixed and wireless networks are increasingly converging towards common connectivity with IP-based core networks. Providing effective end-to-end resource and QoS management in such complex heterogeneous converged network scenarios requires unified, adaptive and scalable solutions to integrate and co-ordinate diverse QoS mechanisms of different access technologies with IP-based QoS. Policy-Based Network Management (PBNM) is one approach that could be employed to address this challenge. Hence, a policy-based framework for end-to-end QoS management in converged networks, CNQF (Converged Networks QoS Management Framework) has been proposed within our project. In this paper, the CNQF architecture, a Java implementation of its prototype and experimental validation of key elements are discussed. We then present a fuzzy-based CNQF resource management approach and study the performance of our implementation with real traffic flows on an experimental testbed. The results demonstrate the efficacy of our resource-adaptive approach for practical PBNM systems

Implementation and Evaluation of Measurement-Based Admission Control Schemes Within a Converged Networks QoS Management Framework

Policy-based network management (PBNM) paradigms provide an effective tool for end-to-end resource
management in converged next generation networks by enabling unified, adaptive and scalable solutions
that integrate and co-ordinate diverse resource management mechanisms associated with heterogeneous
access technologies. In our project, a PBNM framework for end-to-end QoS management in converged
networks is being developed. The framework consists of distributed functional entities managed within a
policy-based infrastructure to provide QoS and resource management in converged networks. Within any
QoS control framework, an effective admission control scheme is essential for maintaining the QoS of
flows present in the network. Measurement based admission control (MBAC) and parameter basedadmission control (PBAC) are two commonly used approaches. This paper presents the implementationand analysis of various measurement-based admission control schemes developed within a Java-based
prototype of our policy-based framework. The evaluation is made with real traffic flows on a Linux-based experimental testbed where the current prototype is deployed. Our results show that unlike with classic MBAC or PBAC only schemes, a hybrid approach that combines both methods can simultaneously result in improved admission control and network utilization efficiency

Design and Implementation of a Measurement-Based Policy-Driven Resource Management Framework For Converged Networks

This paper presents the design and implementation of a measurement-based QoS and resource management framework, CNQF (Converged Networks’ QoS Management Framework). CNQF is designed to provide unified, scalable QoS control and resource management through the use of a policy-based network
management paradigm. It achieves this via distributed functional entities that are deployed to co-ordinate the resources of the transport network through centralized policy-driven decisions supported by measurement-based control architecture. We present the CNQF architecture, implementation of the
prototype and validation of various inbuilt QoS control mechanisms using real traffic flows on a Linux-based experimental test bed.

Dynamic Buffer Management for Multimedia Services in Beyond 3G Wireless Networks

This paper investigates a dynamic buffer man-agement scheme for QoS control of multimedia services in be-yond 3G wireless systems. The scheme is studied in the context of the state-of-the-art 3.5G system i.e. the High Speed Downlink Packet Access (HSDPA) which enhances 3G UMTS to support high-speed packet switched services. Unlike earlier systems, UMTS-evolved systems from HSDPA and beyond incorporate mechanisms such as packet scheduling and HARQ in the base station necessitating data buffering at the air interface. This introduces a potential bottleneck to end-to-end communication. Hence, buffer management at the air interface is crucial for end-to-end QoS support of multimedia services with multi-plexed parallel diverse flows such as video and data in the same end-user session. The dynamic buffer management scheme for HSDPA multimedia sessions with aggregated real-time and non real-time flows is investigated via extensive HSDPA simulations. The impact of the scheme on end-to-end traffic performance is evaluated with an example multimedia session comprising a real-time streaming flow concurrent with TCP-based non real-time flow. Results demonstrate that the scheme can guar-antee the end-to-end QoS of the real-time streaming flow, whilst simultaneously protecting the non real-time flow from starva-tion resulting in improved end-to-end throughput performance

Measurement-based Policy-driven QoS Management in Converged Next Generation Networks

Policy-based management is considered an effective approach to address the challenges of resource management in large complex networks. Within the IU-ATC QoS Frameworks project, a policy-based network management framework, CNQF (Converged Networks QoS Framework) is being developed aimed at providing context-aware, end-to-end QoS control and resource management in converged next generation networks. CNQF is designed to provide homogeneous, transparent QoS control over heterogeneous access technologies by means of distributed functional entities that co-ordinate the resources of the transport network through policy-driven decisions. In this paper, we present a measurement-based evaluation of policy-driven QoS management based on CNQF architecture, with real traffic flows on an experimental testbed. A Java based implementation of the CNQF Resource Management Subsystem is deployed on the testbed and results of the experiments validate the framework operation for policy-based QoS management of real traffic flows.

A Dynamic Buffer Management Scheme for End-to-End QoS Enhancement of Multi-flow Services in HSDPA

End-user multi-flow services support is a crucial aspect of current and next generation mobile networks. This paper presents a dynamic buffer management strategy for HSDPA end-user multi-flow traffic with aggregated real-time and non-real-time flows. The scheme incorporates dynamic priority switching between the flows for transmission on the HSDPA radio channel. The end-to-end performance of the proposed strategy is investigated with an end-user multi-flow session of simultaneous VoIP and TCP-based downlink traffic using detailed HSDPA system-level simulations. Compared to an equivalent static buffer management scheme, the results show that end-to-end throughput performance gains in the non-real-time flow and better HSDPA channel utilization is attainable without compromising the real-time VoIP flow QoS constraints

Buffer Management for Multimedia QoS control over HSDPA Downlink

HSDPA specifications include support for a flexible framework for QoS management. In this paper, it is shown how buffer management could be incorporated into HSDPA QoS framework for 'multimedia' traffic QoS control in the MAC-hs of the Node-B. A time-space-priority (TSP) scheme is proposed as viable buffer management scheme to this effect. Comparative simulation study with other schemes is presented, demonstrating the effectiveness of the TSP buffer management scheme for 'multimedia' service QoS control in HSDPA Node-B data buffers