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Dynamic bandwidth assignment (DBA) schemes for long reach PONs face a suffer from higher upstream channel idle time due to long round trip time (RTT). In ITU PONs, the DBA schemes; Immediate allocation with colorless grant (IACG), Efficient bandwidth utilization (EBU) and GPON redundancy eraser algorithm (GREAL) minimize idle time by sending bandwidth grants to the optical network units (ONUs) every downstream frame (DF). EBU further improves IACG by utilizing unused bandwidth (UBW) of other traffic classes. Sending the grant results every DF requires optical line terminal (OLT) to remember all previous grants sent to ONU during RTT and subtract them from the received queue reports. Since, both IACG and EBU assign the excess bandwidth equally to ONUs. Therefore, the OLT is actually not aware of the complete grant to each traffic class and thus do not subtract these completely from receiving reports. This leads to wastage of bandwidth and higher US delays due to over granting. GREAL resolves this problem by not utilizing the excess bandwidth which also leads to increased US delays. The proposed scheme in this study eliminates this shortcoming by allocating excess bandwidth to each traffic class completely at the OLT. Moreover, the UBW assignment mechanism of EBU is also improved. Simulation results show a 50–85 % reduction in delays of type-2 (T2) and type-3 (T3) traffic classes versus GREAL and IACG and up to 40 % reduction in delays for type-4 (T4) versus EBU.

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Purpose – The purpose of this study is to emphasize the importance of return on investment (ROI) within training programs in Malaysian small and medium enterprises (SMEs). Specifically, this paper focuses on the determinants that may influence the adoption of ROI in the current training evaluation practice. Design/methodology/approach – The paper highlights the internal and external organizational factors that may influence ROI adoption within the Malaysian context. The internal drivers are identified as management support, while the external drivers are policies and regulation, competitive pressure and customer expectation. Findings – Based on a comprehensive review in the human resource field, the main drivers for ROI adoption are identified as management support, policies and regulations, competitive pressure and customer expectation. Practical implications – On the face of fierce national and international competitions, SMEs need to seriously consider investing in higher-level training evaluation, i.e. ROI, to increase its labor quality and subsequently organization’s productivity. Originality/value – Prior studies tend to concentrate on larger organization, whereas research on the adoption of ROI in SMEs has received less attention from the scholars. This study builds a conceptual work based on the integration of internal and external environments in the scope of study rarely analyzed, i.e. Malaysian SMEs. Strong SMEs are undoubtedly important for Malaysia to achieve its vision in becoming a developed nation by end of the decade. It is also worth to note that findings from this study are applicable to other developing countries with similar background to Malaysia.

The integration of optical and wireless technologies at access networks are considered as a future solution which provide both high bandwidth and high mobility in an efficient way. GPON is a suitable candidate for optical backhaul due to the combination of higher data rates, greater split ratio and support for triple play services hence it offers maximum flexibility and cost advantages. On the other hand, recent developments of new radio access technologies and introduction of femtocell base stations provide the potential of offering broadband services and applications to everyone and everywhere. However, the power consumption of this network demands a particular attention because access networks are the largest contributor the network related electricity consumption. Therefore, in this paper we evaluate the power consumption of integrated optical-wireless access network which is based on independent ONU-BS architecture. We proposed a power consumption model for such network and the assessment has been done under different simulation scenarios. The constructed model will provide insight of the energy performance of the integrated access network so that in the network design process, focus can be done to the most energy saving strategies.

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