A New Class of MDS Erasure Codes Based on Graphs

Maximum distance separable (MDS) array codes are XOR-based optimal erasure codes that are particularly suitable for use in disk arrays. This paper develops an innovative method to build MDS array codes from an elegant class of nested graphs, termed \textit{complete-graph-of-rings (CGR)}. We discuss a systematic and concrete way to transfer these graphs to array codes, unveil an interesting relation between the proposed map and the renowned perfect 1-factorization, and show that the proposed CGR codes subsume B-codes as their "contracted" codes. These new codes, termed \textit{CGR codes}, and their dual codes are simple to describe, and require minimal encoding and decoding complexity.Comment: in Proceeding of IEEE Global Communications Conference (GLOBECOM

Penawaran Kursus Bahasa Asing di universiti: meninjau pemilihannya dari perspektif nilai ekonomi

Kursus Bahasa Asing merupakan kursus elektif di universiti tempatan. Terdapat tiga kategori bahasa Asing yang ditawarkan, iaitu bahasa-bahasa Eropah (misalnya bahasa Jerman, Perancis, Sepanyol dan sebagainya), bahasa di Asia Timur (terutamanya bahasa Mandarin, Korea dan Jepun) dan bahasa di Asia Tenggara (seperti bahasa Thai, Burma, Vietnam, Kemboja dan sebagainya). Di antaranya, kursus bahasa Eropah dan Asia Timur, yang dipersepsikan sebagai bahasa Tinggi (bahasa H) menjadi kursus pilihan utama para pelajar. Bahasa Asia Tenggara sebaliknya diabaikan oleh pelajar (dan juga universiti tempatan) dan dianggap sebagai bahasa Rendah (Bahasa L). Dengan kenyataan bahawa negara-negara ASEAN mengalami perkembangan ekonomi yang pesat dan kehadiran ramai penutur yang berbahasa Asia Tenggara di sekitar kita, makalah ini menegaskan tentang kelebihan menguasai bahasa-bahasa serantau daripada bahasa yang dipersepsikan berprestij seperti bahasa di Eropah atau di Asia Timur

Variable sampling interval run sum X‾ chart with estimated process parameters

The X‾ type control chart is often evaluated by assuming the process parameters are known. However, the exact values of process parameters are hardly known and thus Phase-I dataset is needed to estimate them. In this paper, the performance of the variable sampling interval run sum X‾ chart with estimated process parameters is evaluated by using the performance measure of the average of the average time to signal (AATS) and the optimal design of the proposed chart in minimizing the out-of-control AATS is developed. The performance measure of the standard deviation of the average time to signal (SDATS) is then used to identify the number of Phase-I samples (w) needed to have an in-control AATS performance close to its known process parameter case. Results show that large w is needed to minimize the performance gap between known and unknown process parameters cases of the VSI RS X‾ chart

Shelf life determination of durian (Durio zibethinus) paste and pulp upon high pressure processing

Globally, there has been an increase in demand for durian. Therefore, it is important to extend the shelf life and at the same time, maintain the quality of durian. This study investigated the effect of high-pressure processing (HPP) on the shelf life of durian paste and pulp. Specifically, HPP treatments of 500 MPa for 5 min on nylon- and skin film-packed durian pulp, and 600 MPa for 5 min on nylon-packed durian paste were applied. It was found that throughout the 56-day storage period, the total soluble solids (TSS), pH and titratable acidity of durian paste and pulp showed no significant changes (p>0.05). The colour (L* values) of nylon-packed untreated durian pulp showed no significant changes (p>0.05), while the untreated durian paste and skin film-packed durian pulp showed significant changes (p0.05) throughout the storage period. The microbial levels of all the high- pressure (HP)-treated durian samples remained below the detection limit till the end of the storage study. HP-treated durian samples showed lower enzymatic (polygalacturonase and pectin methyl esterase) activities compared to untreated sample throughout the storage period. Sensory evaluation showed no significant difference (p>0.05) between untreated and HP-treated samples. In summary, HPP effectively maintained the overall quality of durian for a minimum of 56 days

Ternary copper(II)-polypyridyl enantiomers: aldol-type condensation, characterization, DNA-binding recognition, BSA-binding and anticancer property

Chiral enantiomers [Cu(phen)(l-threo)(H2O)]NO31 and [Cu(phen)(d-threo)(H2O)]NO32 (threo = threoninate) underwent aldol-type condensation with formaldehyde, with retention of chirality, to yield their respective enantiomeric ternary copper(ii) complexes, viz.l- and d-[Cu(phen)(5MeOCA)(H2O)]NO3·xH 2O (3 and 4; phen = 1,10-phenanthroline; 5MeOCA = 5-methyloxazolidine-4-carboxylate; x = 0-3) respectively. These chiral complexes were characterized by FTIR, elemental analysis, circular dichroism, UV-Visible spectroscopy, fluorescence spectroscopy (FL), molar conductivity measurement, ESI-MS and X-ray crystallography. Analysis of restriction enzyme inhibition by these four complexes revealed modulation of DNA binding selectivity by the type of ligand, ligand modification and chirality. Their interaction with bovine serum albumin was investigated by FL and electronic spectroscopy. With the aid of the crystal structure of BSA, spectroscopic evidence suggested their binding at the cavity containing Trp134 with numerous Tyr residues in subdomain IA. The products were more antiproliferative than cisplatin against cancer cell lines HK-1, MCF-7, HCT116, HSC-2 and C666-1 except HL-60, and were selective towards nasopharyngeal cancer HK-1 cells over normal NP69 cells of the same organ type

Cryopreservation of Neurospheres Derived from Human Glioblastoma Multiforme

Cancer stem cells have been shown to initiate and sustain tumor growth. In many instances, clinical material is limited, compounded by a lack of methods to preserve such cells at convenient time points. Although brain tumor-initiating cells grown in a spheroid manner have been shown to maintain their integrity through serial transplantation in immune-compromised animals, practically, it is not always possible to have access to animals of suitable ages to continuously maintain these cells. We therefore explored vitrification as a cryopreservation technique for brain tumor-initiating cells. Tumor neurospheres were derived from five patients with glioblastoma multiforme (GBM). Cryopreservation in 90% serum and 10% dimethyl sulfoxide yielded greatest viability and could be explored in future studies. Vitrification yielded cells that maintained self-renewal and multipotentiality properties. Karyotypic analyses confirmed the presence of GBM hallmarks. Upon implantation into NOD/SCID mice, our vitrified cells reformed glioma masses that could be serially transplanted. Transcriptome analysis showed that the vitrified and nonvitrified samples in either the stem-like or differentiated states clustered together, providing evidence that vitrification does not change the genotype of frozen cells. Upon induction of differentiation, the transcriptomes of vitrified cells associated with the original primary tumors, indicating that tumor stem-like cells are a genetically distinct population from the differentiated mass, underscoring the importance of working with the relevant tumor-initiating population. Our results demonstrate that vitrification of brain tumor-initiating cells preserves the biological phenotype and genetic profiles of the cells. This should facilitate the establishment of a repository of tumor-initiating cells for subsequent experimental designs

Optimised spectral effects of programmable LED arrays (PLA)s on bioelectricity generation from algal-biophotovoltaic devices.

Funder: Higher Institution Centre of Excellence (HICoE) Fund, Ministry of Education: Air ocean and land interaction; Grant(s): IOES-2014FThe biophotovoltaic cell (BPV) is deemed to be a potent green energy device as it demonstrates the generation of renewable energy from microalgae; however, inadequate electron generation from microalgae is a significant impediment for functional employment of these cells. The photosynthetic process is not only affected by the temperature, CO2 concentration and light intensity but also the spectrum of light. Thus, a detailed understanding of the influences of light spectrum is essential. Accordingly, we developed spectrally optimized light using programmable LED arrays (PLA)s to study the effect on algae growth and bioelectricity generation. Chlorella is a green microalga and contains chlorophyll-a (chl-a), which is the major light harvesting pigment that absorbs light in the blue and red spectrum. In this study, Chlorella is grown under a PLA which can optimally simulate the absorption spectrum of the pigments in Chlorella. This experiment investigated the growth, photosynthetic performance and bioelectricity generation of Chlorella when exposed to an optimally-tuned light spectrum. The algal BPV performed better under PLA with a peak power output of 0.581 mW m-2 for immobilized BPV device on day 8, which is an increase of 188% compared to operation under a conventional white LED light source. The photosynthetic performance, as measured using pulse amplitude modulation (PAM) fluorometry, showed that the optimized spectrum from the PLA gave an increase of 72% in the rETRmax value (190.5 μmol electrons m-2 s-1), compared with the conventional white light source. Highest algal biomass (1100 mg L-1) was achieved in the immobilized system on day eight, which translates to a carbon fixation of 550 mg carbon L-1. When artificial light is used for the BPV system, it should be optimized with the light spectrum and intensity best suited to the absorption capability of the pigments in the cells. Optimum artificial light source with algal BPV device can be integrated into a power management system for low power application (eg. environment sensor for indoor agriculture system)

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Numerical simulation of supercritical flow in open channel

The presence of disturbances such as bends, contraction, expansion, junction, bridge piers in a drainage system is very common in Malaysia. These hydraulic structures often cause the channel flow to choke and form standing waves. The challenges for this numerical model lie in representing supercritical transition and capturing shocks. For this purpose, an unstructured two-dimensional finite-element model is used to solve the governing shallow water equations. This numerical model utilizes a characteristic based Petrov-Galerkin method implemented with shockdetection mechanism. The model testing demonstrates the ability of this numerical model to reproduce the speed and height of flow with the presence of hydraulic structure under different flow conditions. Four experiments, which consist of weir, contraction and 90° expansion, hydraulic jump and bridge pier, were conducted in laboratory Universiti Teknologi Malaysia (UTM). The Reynolds number for these experiments is within the range of 30000 to 47000. The numerical model results are compared quantitatively with experimental results, published numerical simulation and analytical solution. In general, the energy in the model is dissipated too fast and the short wave in the model tends to travel faster. The present model is not suitable for any surface flow that has steep gradients. Overall results show that the numerical model satisfactorily computed the water-surface profiles of the experiments data and exact solutions. The results demonstrate that the numerical model provides an alternative tool in validating theoretical finding and evaluating flow performanc

Hydraulic performance of high-velocity channels in flood-prone areas

The presence of disturbances such as bends, contraction, expansion, junction, bridge piers in a drainage system is very common in Malaysia. These hydraulic structures often cause the channel flow to choke and form standing waves. Numerical modelling is a reasonable approach to study these problems. The challenges for this numerical model lie in representing supercritical transition and capturing shocks. For this purpose, an unstructured two-dimensional finite-element model is used to solve the governing shallow water equations. This numerical model utilizes a characteristic based Petrov-Galerkin method implemented with shock-detection mechanism. The model testing demonstrates the ability of this numerical model to reproduce the speed and height of flow with the presence of channel contractions, weir, and bridge pier under different flow conditions. The numerical model results are compared quantitatively with experimental results, published numerical simulation and analytical solution. The model was also applied to Sg Segget and Sg Sepakat channels in evaluating the channels performance. In general, the numerical model satisfactorily computed the water-surface profiles of the experimental data and exact solutions. The results demonstrate that the numerical model provide an alternative tool in validating theoretical finding and determining appropriate designs for flood channels to meet site-specific criteria