Optimal Packetization Interval for VoIP Applications Over IEEE 802.16 Networks

An analysis of the impact of the packetization interval for constant bit rate traffic has been done in the context of IEEE 802.16 MAC layer. Bandwidth used for overheads which include lower layer headers as well as retransmissions at the MAC layer are considered. An optimal packetization interval selection method for delay sensitive applications such as VoIP is proposed. Enhancements to the Unsolicited Grant Service retransmission strategy are proposed to further improve delay and minimize packet loss while making efficient use of the limited bandwidth resource

Challenges in Applying the DCF Method for Investment Property Valuation in Sri Lanka: Insights from a Delphi Study

This study aimed to identify the challenges of implementing the Discounted Cash Flow (DCF) valuation method for investment properties in Sri Lanka. Through a mixed methodological approach involving the Delphi technique and structured interviews, insights were gathered from industry valuation experts via two Delphi rounds. The study's key findings were derived from the consensus reached among these experts, focusing on data- and valuer-bound factors. One of the primary challenges identified in the Sri Lankan context is the lack of training, which significantly hinders the knowledge and understanding required for implementing the DCF method effectively. Other significant hurdles included obtaining relevant data and accurately determining the discount rate. Imperfections in available data, the absence of a centralized digital data system, and challenges associated with increasing cash flows and market uncertainties also hindered the adoption of the DCF method in Sri Lanka. This study contributes to the existing DCF literature and provides valuable insights for practitioners and future researchers in the field of property valuation in Sri Lanka

Use of Natural Graphite for an Energy Storage Device

Ever growing high concerns over use of safe and low cost devices have provided a substantial attention on natural materials. As such natural graphite which has been deeply integrated into numerous applications is being received a consideration to be used for electrochemical devices. The main objective of this study is to explore the suitability of Sri Lankan natural graphite to serve in electrochemical double layer capacitors (EDLCs). In order to uplift the safety of the device, a gel polymer electrolyte was used instead of a liquid electrolyte. Two identical electrodes were consisted with Sri Lankan natural graphite as the active material and polyvinylidenefluoride as the binder. To prepare the electrolyte, polyvinylidenefluoride co hexafluoropropylene and magnesium perchlorate were used as the polymer and the salt respectively. Cyclic voltammetry test results show that single electrode specific capacitance is depending on the potential window. The percentage reduction of capacitance with continuous cycling was about 28%. Nyquist plot of EDLC further confirm the capacitive nature at low frequency

Towards a global model of accounting education

Purpose - The purpose of this paper is to examine the accounting education systems in three countries - Australia, Japan and Sri Lanka - to inform the development and testing (by application) of a Global Model of Accounting Education

Empirical studies on the performance of banks: A systematic literature review for future research

This paper intends to review research on the performance of banks to identify gaps in the current body of knowledge to justify future research directions. We use a systematic literature review method and review 164 articles from refereed journals. Content analysis reveals that most of the studies are empirical focusing on two aspects i.e. financial performance and efficiency of banks. These studies consider the impact of particular events and contexts on performance and efficiency while testing research hypotheses. However, often there is a lack of a theoretical backing for these studies. We argue that the considered events and contexts affect the risk transformation process under the financial intermediation theory. The efficiency of banks reflects the risk transformation process and causes performance. On the other hand, traditional performance indicators were based on financial measures that do not reflect the components of the risk transformation process. A sound comprehensive risk-based composite measure is required to fill this gap

AzTEC/ASTE 1.1-mm Survey of the AKARI Deep Field South: source catalogue and number counts

We present results of a 1.1 mm deep survey of the AKARI Deep Field South (ADF-S) with AzTEC mounted on the Atacama Submillimetre Telescope Experiment (ASTE). We obtained a map of 0.25 sq. deg area with an rms noise level of 0.32-0.71 mJy. This is one of the deepest and widest maps thus far at millimetre and submillimetre wavelengths. We uncovered 198 sources with a significance of 3.5-15.6 sigma, providing the largest catalog of 1.1 mm sources in a contiguous region. Most of the sources are not detected in the far-infrared bands of the AKARI satellite, suggesting that they are mostly at z ~ 1.5 given the detection limits. We constructed differential and cumulative number counts in the ADF-S, the Subaru/XMM Newton Deep Field (SXDF), and the SSA 22 field surveyed by AzTEC/ASTE, which provide currently the tightest constraints on the faint end. The integration of the best-fit number counts in the ADF-S find that the contribution of 1.1 mm sources with fluxes >=1 mJy to the cosmic infrared background (CIB) at 1.1 mm is 12-16%, suggesting that the large fraction of the CIB originates from faint sources of which the number counts are not yet constrained. We estimate the cosmic star-formation rate density contributed by 1.1 mm sources with >=1 mJy using the best-fit number counts in the ADF-S and find that it is lower by about a factor of 5-10 compared to those derived from UV/optically-selected galaxies at z ~ 2-3. The fraction of stellar mass of the present-day universe produced by 1.1 mm sources with >=1 mJy at z >= 1 is ~20%, calculated by the time integration of the star-formation rate density. If we consider the recycled fraction of >0.4, which is the fraction of materials forming stars returned to the interstellar medium, the fraction of stellar mass produced by 1.1 mm sources decrease to <~10%.Comment: 15 pages, 12 figure, accepted for publication in MNRA

Motion Segmentation of Truncated Signed Distance Function based Volumetric Surfaces

© 2015 IEEE.Truncated signed distance function (TSDF) based volumetric surface reconstructions of static environments can be readily acquired using recent RGB-D camera based mapping systems. If objects in the environment move then a previously obtained TSDF reconstruction is no longer current. Handling this problem requires segmenting moving objects from the reconstruction. To this end, we present a novel solution to the motion segmentation of TSDF volumes. The segmentation problem is cast as CRF-based MAP inference in the voxel space. We propose: a novel data term by solving sparse multi-body motion segmentation and computing likelihoods for each motion label in the RGB-D image space, and, a novel pair wise term based on gradients of the TSDF volume. Experimental evaluation shows that the proposed approach achieves successful segmentations on reconstructions acquired with Kinect Fusion. Unlike the existing solutions which only work if the objects move completely from their initially occupied spaces, the proposed method permits segmentation of objects when they start to move

The detection of lubricating oil viscosity changes in gearbox transmission systems driven by sensorless variable speed drives using electrical supply parameters

Lubrication oil plays a decisive role to maintain a reliable and efficient operation of gear transmissions. Many offline methods have been developed to monitor the quality of lubricating oils. This work focus on developing a novel online method to diagnose oil degradation based on the measurements from power supply system to the gearbox. Experimental studies based on an 10kW industrial gearbox fed by a sensorless variable speed drive (VSD) shows that measurable changes in both static power and dynamic behaviour are different with lube oils tested. Therefore, it is feasible to use the static power feature to indicate viscosity changes at low and moderate operating speeds. In the meantime, the dynamic feature can separate viscosity changes for all different tested cases

A Survey on Simultaneous Wireless Information and Power Transfer

This paper presents a comprehensive study related to simultaneous wireless information and power transfer (SWIPT) in different types of wireless communication setups. Harvesting energy using SWIPT is an appealing solution in the context of extending battery life of wireless devices for a fully sustainable communication system. Strong signal power increases power transfer, but also causes more interference in information transfer, causing realization of the SWIPT challenging problem. This article provides an overview of technical evolution of SWIPT. A survey and qualitative comparison of the existing SWIPT schemes is provided to demonstrate their limitations in the current and 5G networks. Open challenges are emphasized and guidelines are provided to adapt the existing schemes in order to overcome these limitations and make them fit for integrating with the modern and emerging next generation communication networks, such as 5G systems

COMPARATIVE STUDIES ON RAPID AND COST EFFECTIVE PROPAGATION METHODS AND INITIAL ESTABLISHMENT OF THE MEDICINAL PLANT Phyllanthus debilis KLIN EX WILLD (EUPHORBIACEAE)

Phyllanthus debilis Klein ex Willd. (Sinhala - Elapitawakka) is a widely used annual herbused in Ayurvedic medicine. The main objective of this study was to develop simple andcost effective propagation methods and growth media for initial establishment of P.debilis.The experimental design was a completely randomized design. Fresh fruit samples at fourdifferent stages (light green, dark green, blackish green and brownish yellow) of maturitywere used to determine the best maturity stage that gives the highest percentage. Seedsobtained from blackish green fruits gave the highest percentage germination (92 %) whengrown on wet filter paper. Percentage of seed germination in dark green and brownishyellow fruits on wet filter paper were 26 % and 65 % respectively and 22 % and 12 %respectively when coir dust: sand (1: I) medium was used. Seeds obtained from light greenfruits did not germinate. Upper and lower stem cuttings of P. debi/is showed very lowpercentage success 2 % and 7 % respectively. Seed moisture content was determined usingfour seed samples (n = 100) dried at 103·C for 17 hours. The average moisture content of aseed was 15 ± 1 %. Hence it can be regarded as an "intermediate" seed type. The seed.viability was tested at weekly intervals for nine weeks. The highest percentage ofgermination (82 %) was observed in one-week-old seeds. Seed viability decreasedgradually over the nine-week period and none of the seeds germinated after nine weeks ofstorage. Nine different potting media were tested for the initial establishment of P. debi/is.Plants grown (n = 20) in the medium comprising top soil: compost: sand (1: I: I)performed well in terms of plant height, leaf number and root collar diameter than in theother potting media.Financial Assistance provided by Sri Lanka Conservation and Sustainable Use ofMedicinal Plants Project is gratefully acknowledged.