bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensor Modeling For An Electrical Capacitance Tomography System Using Comsol Multiphysics
Authors: Zimam Muhammad Afiq , Mohamad Elmy Johana , Abdul Rahim Ruzairi , Ling Leow Pei
Published: January 2013

Kerja penyelidikan ini membentangkan proses pembinaan model bagi Pengesan Kapasitan Elektrik Tomografi (ECT) menggunakan Perisian Kaedah Elemen Terhingga (Finite Element method–FEM) COMSOL Multiphysics. Meskipun pengesan fizikal adalah dalam bentuk tiga dimensi (3D) tetapi secara amnya sering dimodelkan secara kepingan/ keratan rentas dalam bentuk dua dimensi (2D). Projek ini menunjukkan pendekatan model dalam bentuk geometri 3D dan 2D, linear FEM menggunakan perisian COMSOL Multiphysics dibina adalah untuk mendapatkan nilai kapasitor di antara elektrod apabila medan elektrik dikenakan dan untuk melihat bagaimana pengagihan permittivity di dalam paip yang bertutup menerusi pengesan. Bayang–bayang yang direkacipta dan nilai–nilai diukur dikemukakan dalam bentuk paip yg kosong dan aliran anulus. Model ECT adalah mewakili perkakasan yang sedia ada, ECT mudah alih yang telah dibina oleh Kumpulan Penyelidikan PROTOM UTM.

Kata kunci: Pengesan; model; ECT; COMSOL multiphysics

This work presents the development process for modeling an ECT (Electrical Capacitance Tomography) sensor using FEM software package COMSOL Multiphysics. The physical sensors are 3D dimensional but it has been common to model the slice or the cross–section in 2D. This project shows the modeling approach for 2D and 3D geometries, the linear Finite Element method (FEM) using COMSOL Multiphysics is developed in order to obtain the capacitance between electrodes when an electric field is applied and to obtain the permittivity distribution inside the closed pipe from the sensor. Generated phantoms and measured values are presented for empty and annular pattern. Simulation is verified using phantoms inside the 16 electrode sensor. The ECT model is representative by existing hardware, Portable ECT, PROTOM Research Group UTM.

Key words: Sensor; modeling; ECT; COMSOL multiphysics
Conductometric H2 Gas Sensor With Doped And Dedoped Electropolymerized Polyaniline Nanostructures
Authors: Arsat Rashidah , Arsat Mahyuddin , Breedon Michael , Zadeh Kourosh Kalantar , Wlodarski Wojtek
Published: January 2013

Dalam kertas kerja ini, struktur dan prestasi pengesanan gas oleh polianilin yang berskala nano yang dimendap di atas transduser lithium tantalate. Polimer berkonduksi ini disintesiskan melalui teknik electropolymerization. Struktur permukaan polianilin dicirikan dengan menggunakan Mikroskop Pengesan Elektron (Scanning Electron Microscopy). Didapati bahawa polianiline yang terhasil dipermukaan transducer adalah 3–dimensi struktur dan poros. Pengesan ini kemudian disiasat prestasinya terhadap konsentrasi gas yang berbeza dan berada dalam keadaan suhu bilik.

Kata kunci: Pengesan H2; polianilin, berskala nano; electropolymerization; dop dan nyah–dop

In this work, the structural and gas sensing properties of polyaniline nanostructures deposited on 36° lithium tantalite (LiTaO3) conductometric transducers was investigated. The polyaniline nanostructures were synthesized via an electropolymerization method. The morphology of the nanostructured polyaniline was characterized using Scanning Electron Microscopy (SEM). It was observed that the electropolymerised film was a three–dimensional (3D) porous structure of polyaniline fibers and nanotips. The conductometric sensors were exposed to different concentrations of hydrogen (H2) gas at room temperature.

Key words: H2 sensor; polyaniline; nanostructures; electropolymerization; doped and dedoped
Effects Of Variables On The Production Of Red-Fleshed Pitaya Powder Using Response Surface Methodology
Authors: Che Yunus Mohd Azizi , Lee Ching Yaw , Idham Zuhaili
Published: January 2013

Teknik reka bentuk komposit pusat dalam kaedah gerak balas permukaan (RSM), telah dipilih untuk memeriksa pengaruh parameter-parameter pengeringan sembur terhadap kandungan lembapan dan ketumpatan pukal serbuk buah naga. Pemboleh ubah-pemboleh ubah tak bersandar dengan julat seperti yang disebutkan telah diuji kaji: suhu masukan (156-224°C), kadar aliran suapan (16.6-33.4 ml/min) dan kepekatan maltodextrin (31.6-48.4%). Keputusan menunjukkan bahawa data eksperimen dapat diwakili oleh bentuk polinomial tertib kedua. Bagaimanapun, hanya istilah linear mempunyai pengaruh mutlak terhadap keadaan serbuk. Parameter-parameter terbaik untuk mencapai nilai kandungan lembapan terendah adalah suhu masukan 224°C, kadar aliran suapan 22.9 ml/min dan kepekatan maltodextrin 40%, dengan jangkaan 3.88% kandungan lembapan. Nilai ketumpatan pukal yang maksimum iaitu 0.45 g/ml dicapai pada suhu masukan 156°C, kadar aliran suapan 16.6 ml/min dan kepekatan maltodextrin 48.4%.

Kata kunci: Kaedah gerak balas permukaan; sembur kering; buah naga

Central Composite Design technique from Response Surface Methodology (RSM) was used to investigate the effects of spray drying conditions on red-fleshed pitaya powder moisture content and bulk density. The spray drying independent variables and ranges are inlet air temperature (156-224°C), feed flow rate (16.6-33.4 ml/min) and maltodextrin concentration (31.6-48.4 %). Results showed that the data were adequately fitted to second order polynomial model. However, only linear terms proved to be significant for powder attributes. The best spray drying conditions within the experimental ranges for minimum powder moisture content of 3.88% would be inlet air temperature, feed flow rate and maltodextrin concentration of 224°C, 22.9 ml/min and 40% respectively. The maximum powder bulk density of 0.45 g/ml was obtained at inlet air temperature of 156°C, 16.6 ml/min feed flow rate and 48.4% maltodextrin concentration.

Key words: Response surface methodology; spray-drying; red-fleshed pitaya
Formalisma Hubungan Logikal Dan Visualisasi Hubungan Perawi Hadith
Authors: Shukur Zarina , Fabil Norasikin , Mohd. Noah Shahrul Azman , Salim Juhana
Published: January 2013

Pengajian dalam Sains Hadith melibatkan banyak rujukan terhadap kitab-kitab lama yang ditulis oleh ulama tersohor zaman lampau. Elemen utama dalam pengajian tersebut adalah semakan terhadap kesahihan hadith. Walaupun era teknologi maklumat mempunyai kecanggihannya tersendiri, namun kewibawaan ulama lampau dalam merekodkan maklumat penting serta metodologi semakan kewibawaan hadith masih tidak dapat ditandingi. Oleh itu, kajian ini membincangkan bagaimana maklumat dalam kitab-kitab lampau berkait dengan pengajian Sains Hadith, dapat dipindahkan ke dalam pangkalan data, dan seterusnya dipaparkan secara visual. Untuk sokongan analisis hadith, peraturan formal yang mencerminkan logik rantaian perawi, diikuti dengan ilustrasi pergerakan hadith dengan memvisualkan hubungan antara perawi bagi hadith tersebut dibincangkan. Hubungan paling ringkas iaitu menggunakan daripada X kepada Y adalah asas kepada ilustrasi ini. Manakala hanya maklumat nama perawi yang dipertimbangkan pada masa ini. Seterusnya, satu prototaip Alat Pemvisual Perawi Hadith (APPH) yang berfungsi untuk memaparkan secara visual hubungan ini telah dibangunkan.

Kata kunci: Tertib perkaitan; Ilustrasi perawi hadith; visualisasi

This paper discusses about formal principle that represents the chain of hadith narrators, followed by an illustration of hadith movement by visualizing the relationship among the narrators of the hadith. This illustration is based on the simplest form of relationship that is from X to Y. At a moment, only the narrators name is considered in this initial study. A Hadith Narrators Visualization Tool is developed as a prototype of this work.

Key words: Relationship rule; hadith narrators illustration; visualization
Halangan Kepada Keberkesanan Pelaksanaan Rantaian Bekalan Di Syarikat Pembuatan Perindustrian Kecil Dan Sederhana
Authors: Ab Rahman Mohd Nizam , Wasilan Harlina , Md Deros Baba , Saibani Nizaroyani
Published: January 2013

Walaupun konsep pengurusan rantaian bekalan (PRP) telah diterima oleh industri, namun terdapat beberapa halangan yang dikenal pasti dalam mengaplikasikannya. Tujuan kertas ini adalah untuk mengenal pasti halangan dan permasalahan yang dihadapi oleh industri pembuatan terutamanya di kalangan PKS dalam melaksanakan PRP. Kajian ini dijalankan melalui kaedah pengedaran soal selidik kepada 305 sampel kajian yang terdiri dari syarikat pembuatan perindustrian kecil dan sederhana (PKS). Hasil kajian menyenaraikan halangan yang wujud dalam pelaksanaan PRP di industri seperti; kurangnya tenaga kerja; jurang komunikasi; kurang pengetahuan mengenai PRP; kurang kepercayaan; dan kurangnya sokongan daripada pihak atasan. Penulisan kajian ini adalah membincangkan kajian-kajian terdahulu yang meluas mengenai isu-isu yang berkaitan PRP. Kajian ini turut mencadangkan penambahbaikan dalam PRP yang mungkin dapat dijadikan rujukan oleh penyelidik akan datang.

Kata kunci: Pengurusan rantaian bekalan; perusahaan kecil dan sederhana; halangan pengurusan rantaian bekalan; kepentingan rantaian bekalan; amalan rantaian bekalan

Eventhough supply chain management (SCM) concept has been accepted by the industry, there are several barriers with were identified during its application. The purpose of this research is to identify the obstacles and problems faced by manufacturing industry especially among small medium enterprices (SMEs) in implementing SCM. The results identified obstacles in SCM implementation in industry which consists of; lack of workforce; lack of communication; lack of knowledge; lack of trust; and lack of support from the upper management. Extensive discussion based on previous studies/researches related to SCM was done in this research.

Key words: Supply chain management; small medium-sized enterprises; obstacle to supply chain management; importants of supply chain; supply chain practice
Carbon Dioxide Reforming Of Methane By Catalytic–Plasma Reactor Over Cu/Zn/γ–Al2O3
Authors: Nikoo Maryam Khoshtinat , Sharifi Mohammad Ali , Saidina Amin Noraishah
Published: January 2013

Dalam kajian semasa, pengaruh kuasa input untuk penukaran CH4 dan CO2 ke syngas disiasat di dalam kedua–dua reaktor silinder plasma DBD dan reaktor plasma pemangkin. Diperhatikan bahawa untuk kedua-dua reaktor, input kuasa yang lebih tinggi menyokong tindak balas pemecahan dan bukannya penggabungan semula perantaraan ringan kepada hidrokarbon yang lebih berat, meningkatkan hasil H2. Sementara itu, kehadiran mangkin Cu/Zn/Al2O3 mempertingkatkan pengeluaran H2 daripada 16.5% kepada 19.1%, manakala nisbah H2/CO kekal hampir malar berhampiran nilai 1, nisbah yang sesuai untuk proses FTS.

Kata kunci: Plasma; catalytic, hydrogen; dry reforming of methane

In the current study, the influence of input power for conversion of CH4 and CO2 into syngas was investigated in both DBD plasma and catalytic–plasma cylindrical reactors. It was observed that for both reactors, higher input power favored fragmentation reactions rather than recombination of light intermediates into heavier hydrocarbons, improving H2 yield. Meanwhile, the presence of Cu/Zn/Al2O3 catalyst enhanced the H2 yield from 16.5 % to 19.1%, while the H2/CO ratio remained almost constant near unity, the suitable ratio for FTS processes.

Key words: Plasma, catalytic, hydrogen, dry reforming of methane
Improved Oil Recovery By Application Of Ultrasonic Stimulated Waterflooding
Authors: Mohammadian Erfan , Shirazi Mohammad Amin , Parak Mahdi , Idris Ahmad Kamal , Junin Radzuan
Published: January 2013

Application of ultrasonic waves as an unconventional enhanced oil recovery method has been a point of interest for some decades. However, despite number of researches on ultrasonic applications, the influencing mechanisms are not fully comprehended. The aim of this study is to experimentally investigate the effects of ultrasonic waves on recovery of waterflooding and to discuss the mechanisms involved. Series of straight (normal) and ultrasonic stimulated waterflooding experiments were conducted on a long unconsolidated sand pack using ultrasonic transducers. Kerosene, vaseline and engine oil were used as non wet phase in the system. Moreover, a series of supplementary experiments were conducted using ultrasonic bath in order to enhance the understanding about contributing mechanisms. 2–16% increase in the recovery of waterflooding was observed. Emulsification, viscosity reduction and cavitation were identified as contributing mechanisms.

Key words: Ultrasonic waves; enhanced oil recovery; waterflooding; emulsification
The Influence Of Vessel Volume And Equivalence Ratio In Vented Gas Explosions
Authors: Kasmani R.M. , Andrews G.E. , Phylaktou H.N.
Published: January 2013

Experiments of vented gas explosions involving two different cylinder vessel volumes (0.2 and 0.0065 m3) were reported. It was found that self–acceleration and larger bulk flame trapped inside the vessel are the main factor enhancing the overpressure attained in 0.2 m3 vessel. There was about 2 to 7 times increase in ratio of pressure and flame speeds on both vessels at the same equivalence ratio and K which can be considered as turbulent enhancement factor, β. The comparison with previous work has shown over–prediction results as compared to the present study.

Key words: Vented gas explosion; self acceleration; turbulent enhancement factor; hot spot
Degrading Drilling Fluid Filter Cake Using Effective Microorganisms
Authors: Ismail Issham , Illias Rosli , Abd. Mubin Amy Shareena , Machitin Masseera
Published: January 2013

The effective cleanup of filter cakes in long, horizontal open-hole completions can maximize an oil well’s productivity. A cleaning solution was formulated which comprised effective microorganisms and a viscoelastic surfactant in order to degrade filter cakes of water-based mud. Generally, the effectiveness of the microorganisms in degrading filter cakes is influenced by temperature and its concentration. To overcome the problem, the viscoelastic surfactant has been used to extend the application of temperature range and increase the viscosity of the cleaning solution. Laboratory studies were conducted to examine the effectiveness of the microorganisms in degrading filter cakes. The apparent viscosity of cleaning solution was measured as a function of shear rate (102.2 s and 1022 s ) and temperature (25 to 80°C). The surface tension of the cleaning solution was measured at room temperature. Static fluid loss tests were performed using the HPHT Filter Press in order to determine the effectiveness of the cleaning solution in degrading filter cake at different temperatures ranging from 100°F to 300°F. Experimental results showed that the cleaning solution could effectively degrade the filter cake. Soaking process was performed until 48 hours and it showed that at temperature 200°F and below, the pure effective microorganisms achieved the highest efficiency of filter cake degradation, i.e. 34.9%. However, at temperature 300°F, cleaning solution that contained effective microorganisms and higher concentration of viscoelastic surfactant was found to perform better. The viscoelastic surfactant succeeded in increasing the viscosity of the cleaning solution, thus enhanced the rate of degradation of filter cakes, i.e. 33.4% at 300°F. The surface tension of the cleaning solution did not change significantly at various concentrations at room temperature.
Experimental Investigation on Cold-formed Steel Beams under Pure Bending
Authors: Lee Yeong Huei , Lee Yee Ling , Tan Cher Siang
Published: January 2013

This paper presents the flexural behaviour of cold-formed double lipped channels beams under pure bending action. Two channel sections are bolted back-to-back to form an I-shape structural beam member. A series of six experiment tests were carried out on beam specimens DC200 and DC250, each with 200 mm depth and 250 mm depth respectively. The thickness of beam section is 2 mm and the design yield strength is 350 N/mm2. All beams failed at local buckling at top-flange due to lateral instability of the cold-formed steel structural members. The moment resistance for DC200 is 17.87 kNm and DC250 is 31.53 kNm. The experimental results are compared to theoretical resistance prediction based on British Standard and Eurocode. The comparison showed that the experimental moment capacity is lower than the theoretical bending moment resistance but higher than theoretical buckling moment resistance from Eurocode. This showed that a better agreement is achieved between experimental data and Eurocode buckling moment resistance for cold-formed steel beam under pure bending.

Kertas kerja ini membentangkan sifat lenturan rasuk keluli tergelek sejuk di bawah tindakan lenturan tulen. Dua channel dihimpunkan berkembar dan diperketatkan dengan bolt untuk membentuk rasuk struktur bentuk-I. Satu siri ujian lenturan telah dijalankan ke atas spesimen rasuk DC200 dan DC250, dengan kedalaman 200 mm dan 250 mm masing-masing. Ketebalan keratan rasuk adalah 2 mm dan kekuatan reka bentuk adalah 350 N/mm2. Semua rasuk gagal pada momen kilasan sisi di bahagian atas bebibir akibat ketakstabilan sisi anggota keluli tergelek sejuk. Rintangan momen bagi DC200 adalah 17.87 kNm dan DC250 adalah 31.53 kNm. Keputusan eksperimen dibanding dengan ramalan teori yang berdasarkan British Standard dan Eurocodes. Perbandingan tersebut menunjukkan bahawa rintangan momen lenturan eksperimen adalah lebih rendah daripada ramalan teori momen lenturan tetapi lebih tinggi daripada ramalan teori momen rintangan kilasan sisi mengikut Eurocode. Ini menunjukkan bahawa persetujuan baik dicapai di antara keputusan eksperimen dengan ramalan teori Eurocode momen rintangan kilasan sisi bagi rasuk keluli tergelek sejuk.
Pengurangan Pelepasan Emisi dari Pembakar Lapisan Terbendalir Menggunakan Tempurung Kelapa Sawit Sebagai Bahan Api
Authors: Mohd Jaafar Mohammad Nazri , Permatasari Rosyida , Mohd Sobree Mohd Nazar Yakin
Published: January 2013

Emissions released from fluidized bed combustor (FBC) are highly dependent on several operating parameters, for example, temperature, staged air, excess air, fuel feed rate, and fuel properties. This paper presents results of experiments conducted using air staging technique on a laboratory scale fluidized bed rig, using palm shells as fuel oil and silica sand as an inert medium. Silica sand was used to ensure a sustainable fuel ignition and stable combustion occurs in the FBC. Emission of CO and NOx emissions, and temperatures along the height of the bed and flue were measured. The experimental results show that the axial temperature profile along the height was proportionally reduced with bed height of FBC. CO and NOx emissions obtained exhibit lower values for the air staged combustion.

Pelepasan emisi dari pembakar lapisan terbendalir (FBC) adalah sangat bergantung kepada beberapa parameter kendalian sebagai contoh: suhu, udara berperingkat, udara berlebihan, kadar suapan bahan api, dan sifat bahan api. Kertas kerja ini mempersembahkan keputusan eksperimen yang dilaksanakan menggunakan teknik pemeringkatan udara ke atas rig lapisan terbendalir skala makmal, menggunakan tempurung kelapa sawit sebagai bahan api dan pasir silika sebagai bahan perantara lengai. Pasir silica telah digunakan untuk memastikan pencucuhan bahan api mampan dan pembakaran stabil berlaku di dalam FBC. Pelepasan gas emisi CO dan NOx serta suhu sepanjang ketinggian pembakar dan juga dalam serombong diukur. Keputusan ujikaji menunjukkan bahawa profil suhu paksi berkurangan secara berkadaran sepanjang ketinggian FBC. Pelepasan CO dan NOx yang diperolehi mempamerkan nilai yang lebih rendah untuk keadaan pembakaran dengan pemeringkatan udara.
Représentations banales de
Authors: Mínguez Alberto , Sécherre Vincent
Published: January 2013

Let${\rm F}$be a non-Archimedean locally compact field of residue characteristic$p$, let${\rm D}$be a finite-dimensional central division${\rm F}$-algebra and let${\rm R}$be an algebraically closed field of characteristic different from$p$. We definebanalirreducible${\rm R}$-representations of the group${\rm G}={\rm GL}_{m}({\rm D})$. This notion involves a condition on the cuspidal support of the representation depending on the characteristic of${\rm R}$. When this characteristic is banal with respect to${\rm G}$, in particular when${\rm R}$is the field of complex numbers, any irreducible${\rm R}$-representation of${\rm G}$is banal. In this article, we give a classification of all banal irreducible${\rm R}$-representations of${\rm G}$in terms of certain multisegments, called banal. When${\rm R}$is the field of complex numbers, our method provides a new proof, entirely local, of Tadić’s classification of irreducible complex smooth representations of${\rm G}$.
Maintaining the T Cell Status Quo
Authors: Obhrai Jagdeep S.
Published: January 2013

Under lymphopenic conditions, T cells work hard to maintain static peripheral numbers.
Statins Beyond Heart Disease: A New Treatment for the Sepsis Syndrome?
Authors: Zeki Amir A.
Published: January 2013

Statin treatment may prevent the progression of sepsis and onset of organ failure.
Inferences on the origins of polyploidTurneraspecies (Passifloraceae) based on molecular data
Authors: López Alicia , Fernández Aveliano , Shore Joel S.
Published: January 2013

We explore the evolution of polyploids in subseries Turnera, testing hypotheses on their origins using DNA sequences (partial ndhF and trnT-L) from the plastid genome, as well as sequences of the nuclear ribosomal internal transcribed spacer (ITS). We construct phylogenies (with both Bayesian and maximum parsimony methods) using both the plastid and ITS sequences. We test hypotheses concerning the genome contributors to polyploids where previous cytogenetic studies had designated various diploid species as possessing A or C genomes and had proposed various genomic constitutions for the polyploids. Our analyses support the occurrence of a C genome clade of species and the origin of autooctoploid T. fernandezii Arbo from T. grandiflora (Urb.) Arbo (a C genome diploid). Nuclear ITS data support the hypothesis that T. concinna Arbo (an A genome species) contributed a genome to the segmental allotetraploid T. grandidentata (Urb.) Arbo, whereas analyses of ndhF and trnT-L sequences did not lead to identification of the plastid (or additional nuclear genome) donor. Our analyses support the origins of allooctoploids T. aurelii Arbo and T. cuneiformis Poir. from hexaploid T. orientalis (Urb.) Arbo. We found no evidence that hexaploid T. velutina Presl. possesses a C genome. We provide evidence, using Bayes factors, supporting the hypothesis that the segmental allohexaploids have had independent origins.
Computational study on the deamination reaction of adenine with OH−/nH2O (n= 0, 1, 2, 3) and 3H2O
Authors: Alrawashdeh Ahmad I. , Almatarneh Mansour H. , Poirier Raymond A.
Published: January 2013

Deamination of adenine is one of several forms of premutagenic lesions occurring in DNA. In the present study, mechanisms for the deamination reaction of adenine with OH−/nH2O (n = 0, 1, 2, 3) and 3H2O were investigated. HF/6-31G(d), B3LYP/6-31G(d), MP2/6-31G(d), and B3LYP/6-31+G(d) levels of theory were employed to search for and optimize all geometries. Energies were calculated at the G3MP2B3 and CBS-QB3 levels of theory. The effect of solvent (water) was computed using the polarizable continuum model (PCM). Intrinsic reaction coordinate (IRC) calculations were performed for all transition states. Five pathways were investigated for the deamination reaction of adenine with OH−/nH2O and 3H2O. The first four pathways (A–D) are initiated by deprotonation at the amino group of adenine by OH−, while pathway E is initiated by tautomerization of adenine. For all pathways the next two steps involve formation of a tetrahedral intermediate followed by dissociation to products via a 1,3-proton shift. Deamination with a single OH−has a high activation barrier (190 kJ mol−1using the G3MP2B3 level) for the rate-determining step. The addition of one water molecule reduces this barrier by 68 kJ mol−1at the G3MP2B3 level. Adding additional water molecules decreases the overall activation energy of the reaction, but the effect becomes smaller with each additional water molecule. The most plausible mechanism is pathway E, the deamination reaction of adenine with 3H2O, with an overall G3MP2B3 activation energy of 139 and 137 kJ mol−1for the gas phase and PCM, respectively. This barrier is lower than that for the deamination with OH−/3H2O by 6 and 2 kJ mol−1for the gas phase and PCM, respectively.
Optical and radiative properties of Nd3+-doped lead tellurite borate glasses
Authors: Shigihalli N.B. , Rajaramakrishna R. , Anavekar R.V.
Published: January 2013

Glass samples of composition (in mol%) 20PbO-20TeO2-(60 – x)B2O3-xNd2O3 (x = 0, 1, 2, 3, 4) were prepared by melt quenching. The glassy nature of as-quenched samples was established via differential scanning calorimetry. The amorphous nature of the glasses was confirmed via powder X-ray diffraction measurements. Judd–Ofelt (JO) analysis based on UV–visible absorption spectra was performed to determine JO parameters Ωλ (λ = 2, 4, 6). The observed trend is Ω2 > Ω6 > Ω4. The large value of Ω2 indicates the presence of covalent bonding between the Nd3+ ions and the surrounding ligands. Radiative properties, such as radiative transition probabilities, branching ratios, and radiative lifetimes are estimated. The glass samples have relatively high branching ratio, and their emission (Aem) to excited state absorption (AESA) intensity ratio is higher than one for the 4F3/2 → 4I11/2 transition, indicating that the prepared glasses may have potential laser applications.
Revisiting Knowledge Management Systems: Exploring Factors Influencing the Choices of Knowledge Management Systems in Knowledge-Intensive Organisations
Authors: Makani Joyline
Published: January 2013

Limited research attention has been directed toward exploring ways in which organisations' understanding of their activities and the contexts in which their workers work influence the organisations' choice, design, and implementation of knowledge management systems (KMS). In particular, little research and insights exist to guide the successful development and implementation of KMS in knowledge-intensive organisations (KIOs). This oversight is somewhat surprising given that knowledge is a key asset in KIOs and one might therefore expect the design of systems that are used to manage knowledge of paramount interest to KIO researchers and practitioners. Using primarily grounded theory approach this study examines how KIO defining factors, KIO organisational knowledge-intensity attributes and knowledge worker activities relate to the choice of KMS in KIOs. Results of this analysis suggest that both organisational knowledge-intense attributes and knowledge-intense worker activities inform the choice and application of KMS in KIOs. Notably, the results revealed significant differences among participants in their choices of KMS, pointing to the fact that managers and practitioners in KIOs critically consider knowledge-intense factors defining their organisations when choosing and implementing KMS. This study contributes to the knowledge management (KM) literature in general and in particular to the KMS in KIOs theory and practice, where limited attention has been paid to the various ways knowledge-intense organisational and worker-related factors may influence KMS choices, design, and adoption and ultimately organisational KM effectiveness.
Better Balanced Economies — A Management Challenge for the 3rd Millennium
Authors: Barachini Franz , Stary Chris
Published: January 2013

The incorporation of non-economic indicators in corporate management systems could help to bridge the gap between poor and rich economies. We propose the capitalisation of labour costs, the provision for costs caused in indirect value chains, environmental and social measures in scorecards, new remuneration schemas for managers, and a change in management attitudes towards knowledge management. The application of the combination of the proposed concepts could positively influence the distribution of wealth and resources, as societies could become more balanced world-wide. We are convinced that the proposed scorecard measures and the necessary change in management behaviour must be driven and supported by knowledge managers operating in world-wide value chains.
Organisational Structure, Community of Practice and Patient Safety
Authors: Kim Yong-Mi , Newby-Bennett Donna
Published: January 2013

Knowledge sharing has been proposed as one of the most effective ways to reduce medical errors, yet research on knowledge sharing with regard to patient safety is sparse. Because employees' knowledge behaviours are enabled or constrained by organisational structures, knowledge sharing can be nurtured or suppressed by organisational structures such as rules and policies. As such, this study integrated organisational structure into the concept of community of practice (CoP) and holistically investigated knowledge sharing with regard to patient safety in the healthcare industry.
Contents-Analysis Support for Better Reference to Technical Papers
Authors: Watanabe Toyohide , Aoki Masato
Published: January 2013

It is not always easy, not only for beginners but also for experts, to find out newly research subjects or grasp analytically research trends (or directions). This work is one of the intelligent tasks. Traditionally, some investigations or research projects focused on the challengeable task of human-oriented creativeness: The efforts are very stable and the results make the basic framework or fundamental ideas clear one by one for strictly-constrained application of human-activity. This task is closely dependent on the global framework of knowledge management with respect to the support from human creative activity. In this paper, we discuss a computer-support method to arrange already-read papers analytically and then discuss the research topics related to currently focused research fields or research trends derived from the existing papers and researcher's interests. Our idea is to realise this paper inquiry method in three procedural steps, such as arranging paper contents, grasping relationships among papers and investigating research subjects followed by already-referred papers, and also make users interact with individually-generated results by controlling spirally three steps.
Maximizing Conjunctive Views in Deletion Propagation
Authors: Kimelfeld Benny , Vondrák Jan , Williams Ryan
Published: January 2013

In deletion propagation, tuples from the database are deleted in order to reflect the deletion of a tuple from the view. Such an operation may result in the (often necessary) deletion of additional tuples from the view, besides the intentionally deleted one. The article studies the complexity of deletion propagation, where the view is defined by a conjunctive query (CQ), and the goal is to maximize the number of tuples that remain in the view. Buneman et al. showed that for some simple CQs, this problem can be solved by a straightforward algorithm, which is called here the unidimensional algorithm. The article identifies additional cases of CQs where the unidimensional algorithm succeeds, and in contrast, shows that for some other CQs the problem is NP-hard to approximate better than some constant ratio. In fact, it is shown here that among the CQs without self joins, the hard CQs are exactly the ones that the unidimensional algorithm fails on. In other words, the following dichotomy result is proved: for every CQ without self joins, deletion propagation is either APX-hard or solvable (in polynomial time) by the unidimensional algorithm.

The article then presents approximation algorithms for certain CQs where deletion propagation is APX-hard. Specifically, two constant-ratio (and polynomial-time) approximation algorithms are given for the class of sunflower CQs (i.e., CQs having a sunflower hypergraph) without self joins. The first algorithm, providing the approximation ratio 1 − 1/
e
, is obtained by formulating the problem at hand as that of maximizing a monotone submodular function subject to a matroid constraint, and then using a known algorithm for such maximization. The second algorithm gives a smaller approximation ratio, 1/2, yet in polynomial time even under combined complexity. Finally, it is shown that self joins can significantly harden approximation in deletion propagation.
Worst-Case I/O-Efficient Skyline Algorithms
Authors: Sheng Cheng , Tao Yufei
Published: January 2013

We consider the
skyline problem
(aka the
maxima problem
), which has been extensively studied in the database community. The input is a set
P
of
d
-dimensional points. A point
dominates
another if the coordinate of the former is at most that of the latter on every dimension. The goal is to find the
skyline
, which is the set of points
p
 ∈ 
P
such that
p
is not dominated by any other point in
P
.

The main result of this article is that, for any fixed dimensionality
d
 ≥ 3, in external memory the skyline problem can be settled by performing
O
((
N
/
B
)log
M/B
d−2
(
N
/
B
)) I/Os in the worst case, where
N
is the cardinality of
P, B
the size of a disk block, and
M
the capacity of main memory. Similar bounds can also be achieved for computing several skyline variants, including the
k-dominant skyline, k-skyband
, and
α-skyline
. Furthermore, the performance can be improved if some dimensions of the data space have small domains. When the dimensionality
d
is not fixed, the challenge is to outperform the naive algorithm that simply checks all pairs of points in
P
×
P
. We give an algorithm that terminates in
O
((
N
/
B
) log
d − 2
N
) I/Os, thus beating the naive solution for any
d
 = 
O
(log
N
/ log log
N
).
Finding Alternative Shortest Paths in Spatial Networks
Authors: Xie Kexin , Deng Ke , Shang Shuo , Zhou Xiaofang , Zheng Kai
Published: January 2013

Shortest path query is one of the most fundamental queries in spatial network databases. There exist algorithms that can process shortest path queries in real time. However, many complex applications require more than just the calculation of a single shortest path. For example, one of the common ways to determine the importance (or price) of a vertex or an edge in spatial network is to use Vickrey pricing, which intuitively values the vertex
v
(or edge
e
) based on how much harder for travelling from the sources to the destinations without using
v
(or
e
). In such cases, the
alternative shortest paths
without using
v
(or
e
) are required. In this article, we propose using a precomputation based approach for both single pair alternative shortest path and all pairs shortest paths processing. To compute the alternative shortest path between a source and a destination efficiently, a naïive way is to precompute and store all alternative shortest paths between every pair of vertices avoiding every possible vertex (or edge), which requires
O
(
n
4
) space. Currently, the state of the art approach for reducing the storage cost is to choose a subset of the vertices as center points, and only store the single-source alternative shortest paths from those center points. Such approach has the space complexity of
O
(
n
2
log
n
). We propose a storage scheme termed
iSPQF
, which utilizes shortest path quadtrees by observing the relationships between each avoiding vertex and its corresponding alternative shortest paths. We have reduced the space complexity from the naïive
O
(
n
4
) (or the state of the art
O
(
n
4
log
n
)) to
O
(min(
γ, L
)
n
1.5
) with comparable query performance of
O
(
K
), where
K
is the number of vertices in the returned paths,
L
is the diameter of the spatial network, and
γ
is a value that depends on the structure of the spatial network, which is empirically estimated to be 40 for real road networks. Experiments on real road networks have shown that the space cost of the proposed iSPQF is scalable, and both the algorithms based on iSPQF are efficient.
Expressive Languages for Path Queries over Graph-Structured Data
Authors: Barceló Pablo , Libkin Leonid , Lin Anthony W. , Wood Peter T.
Published: January 2013

For many problems arising in the setting of graph querying (such as finding semantic associations in RDF graphs, exact and approximate pattern matching, sequence alignment, etc.), the power of standard languages such as the widely studied conjunctive regular path queries (CRPQs) is insufficient in at least two ways. First, they cannot output paths and second, more crucially, they cannot express
relationships
among paths.

We thus propose a class of
extended
CRPQs, called ECRPQs, which add regular relations on tuples of paths, and allow path variables in the heads of queries. We provide several examples of their usefulness in querying graph structured data, and study their properties. We analyze query evaluation and representation of tuples of paths in the output by means of automata. We present a detailed analysis of data and combined complexity of queries, and consider restrictions that lower the complexity of ECRPQs to that of relational conjunctive queries. We study the containment problem, and look at further extensions with first-order features, and with nonregular relations that add arithmetic constraints on the lengths of paths and numbers of occurrences of labels.
Approximating minimum-cost connectivity problems via uncrossable bifamilies
Authors: Nutov Zeev
Published: January 2013

We give approximation algorithms for the Survivable Network problem. The input consists of a graph
G
= (
V,E
) with edge/node-costs, a node subset
S
⊆
V
, and connectivity requirements {
r
(
s,t
):
s,t
∈
T
⊆
V
}. The goal is to find a minimum cost subgraph
H
of
G
that for all
s,t
∈
T
contains
r
(
s,t
) pairwise edge-disjoint
st
-paths such that no two of them have a node in
S
∖ {
s,t
} in common. Three extensively studied particular cases are: Edge-Connectivity Survivable Network (
S
= ∅), Node-Connectivity Survivable Network (
S
=
V
), and Element-Connectivity Survivable Network (
r
(
s,t
) = 0 whenever
s
∈
S
or
t
∈
S
). Let
k
= max

s,t ∈ T

r
(
s,t
). In Rooted Survivable Network, there is
s
∈
T
such that
r
(
u,t
) = 0 for all
u
≠
s
, and in the Subset
k
-Connected Subgraph problem
r
(
s,t
) =
k
for all
s,t
∈
T
.

For edge-costs, our ratios are
O
(
k
log
k
) for Rooted Survivable Network and
O
(
k
2
log
k
) for Subset
k
-Connected Subgraph. This improves the previous ratio
O
(
k
2
log
n
), and for constant values of
k
settles the approximability of these problems to a constant.

For node-costs, our ratios are as follows.

—
O
(
k
log |
T
|) for Element-Connectivity Survivable Network, matching the best known ratio for Edge-Connectivity Survivable Network.

—
O
(
k
2
log |
T
|) for Rooted Survivable Network and
O
(
k
3
log |
T
|) for Subset
k
-Connected Subgraph, improving the ratio
O
(
k
8
log
2
|
T
|).

—
O
(
k
4
log
2
|
T
|) for Survivable Network; this is the first nontrivial approximation algorithm for the node-costs version of the problem.
A compact routing scheme and approximate distance oracle for power-law graphs
Authors: Chen Wei , Sommer Christian , Teng Shang-Hua , Wang Yajun
Published: January 2013

Compact routing addresses the tradeoff between table sizes and stretch, which is the worst-case ratio between the length of the path a packet is routed through by the scheme and the length of an actual shortest path from source to destination. We adapt the compact routing scheme by Thorup and Zwick [2001] to optimize it for power-law graphs. We analyze our adapted routing scheme based on the theory of unweighted random power-law graphs with fixed expected degree sequence by Aiello et al. [2000]. Our result is the first analytical bound coupled to the parameter of the power-law graph model for a compact routing scheme.

Let
n
denote the number of nodes in the network. We provide a
labeled
routing scheme that, after a stretch--5 handshaking step (similar to DNS lookup in TCP/IP), routes messages along stretch--3 paths. We prove that, instead of routing tables with
Õ
(
n
1/2
) bits (
Õ
suppresses factors logarithmic in
n
) as in the general scheme by Thorup and Zwick, expected sizes of
O
(

n
γ

log
n
) bits are sufficient, and that all the routing tables can be constructed at once in expected time
O
(

n
1+γ

log
n
), with γ = τ-22/τ-3 + ε, where τ∈(2,3) is the power-law exponent and ε 0 (which implies ε < γ < 1/3 + ε). Both bounds also hold with probability at least 1-1/
n
(independent of ε). The routing scheme is a labeled scheme, requiring a stretch--5 handshaking step. The scheme uses addresses and message headers with
O
(log
n
log log
n
) bits, with probability at least 1-
o
(1). We further demonstrate the effectiveness of our scheme by simulations on real-world graphs as well as synthetic power-law graphs.

With the same techniques as for the compact routing scheme, we also adapt the approximate distance oracle by Thorup and Zwick [2001, 2005] for stretch-3 and we obtain a new upper bound of expected
Õ
(
n
1+γ
) for space and preprocessing for random power-law graphs. Our distance oracle is the first one optimized for power-law graphs. Furthermore, we provide a linear-space data structure that can answer 5--approximate distance queries in time at most
Õ
(
n
1/4+ε
) (similar to γ, the exponent actually depends on τ and lies between ε and 1/4 + ε).
Algorithms and complexity for periodic real-time scheduling
Authors: Bonifaci Vincenzo , Chan Ho-Leung , Marchetti-Spaccamela Alberto , Megow Nicole
Published: January 2013

We investigate the preemptive scheduling of periodic tasks with hard deadlines. We show that, even in the uniprocessor case, no pseudopolynomial-time algorithm can test the feasibility of a task system within a constant speedup bound, unless P = NP. This result contrasts with recent results for sporadic task systems. For two special cases, synchronous task systems and systems with a constant number of different task types, we provide the first polynomial-time constant-speedup feasibility tests for multiprocessor platforms. Furthermore, we show that the problem of testing feasibility is coNP-hard for synchronous multiprocessor task systems. The complexity of some of these problems has been open for a long time.

We also propose a weight maximization variant of the feasibility problem, where every task has a nonnegative weight, and the goal is to find a subset of tasks that can be scheduled feasibly and has maximum weight. We give the first constant-speed, constant-approximation algorithm for the case of synchronous task systems, together with related hardness results.
The Apple-Samsung lawsuits
Authors: Cusumano Michael A.
Published: January 2013

In search of a middle ground in the intellectual property wars.
Beyond location
Authors: Desai Deven
Published: January 2013

Viewing evolving data security issues as engineering problems to be solved.
Human mobility characterization from cellular network data
Authors: Becker Richard , Cáceres Ramón , Hanson Karrie , Isaacman Sibren , Loh Ji Meng , Martonosi Margaret , Rowland James , Urbanek Simon , Varshavsky Alexander , Volinsky Chris
Published: January 2013

Anonymous location data from cellular phone networks sheds light on how people move around on a large scale.
Abstractions for genomics
Authors: Bafna Vineet , Deutsch Alin , Heiberg Andrew , Kozanitis Christos , Ohno-Machado Lucila , Varghese George
Published: January 2013

Large genomic databases with interactive access require new, layered abstractions, including separating "evidence" from "inference."
Future Tense: Share my enlightenment
Authors: Rucker Rudy
Published: January 2013

From the intersection of computational science and technological speculation, with boundaries limited only by our ability to imagine what could be.

I self-publish, and you get to sail my aether wave for free.
Ubiquity symposium: The science in computer science
Authors: Cerf Vinton G.
Published: January 2013

The first article in this symposium, which originally appeared in the Communication the ACM, is courtesy of ACM President Vinton Cerf. Earlier this year, he called on all ACM members to commit to building a stronger science base for computer science. Cerf cites numerous open questions, mostly in software development, that cry out for experimental studies.
SIGACT News Complexity Theory Column 76
Authors: Hemaspaandra Lane A. , Williams Ryan
Published: January 2013

Heuristic approaches often do so well that they seem to pretty much always give the right answer. How close can heuristic algorithms get to always giving the right answer, without inducing seismic complexity-theoretic consequences? This article first discusses how a series of results by Berman, Buhrman, Hartmanis, Homer, Longpré, Ogiwara, Schöning, and Watanabe, from the early 1970s through the early 1990s, explicitly or implicitly limited how well heuristic algorithms can do on NP-hard problems. In particular, many desirable levels of heuristic success cannot be obtained unless severe, highly unlikely complexity class collapses occur. Second, we survey work initiated by Goldreich and Wigderson, who showed how under plausible assumptions deterministic heuristics for randomized computation can achieve a very high frequency of correctness. Finally, we consider formal ways in which theory can help explain the effectiveness of heuristics that solve NP-hard problems in practice.
Computational geometry column 54
Authors: Dumitrescu Adrian , Tóth Csaba D.
Published: January 2013

This column is devoted to non-crossing configurations in the plane realized with straight line segments connecting pairs of points from a finite ground set. Graph classes of interest realized in this way include matchings, spanning trees, spanning cycles, and triangulations. We review some problems and results in this area. At the end we list some open problems.
Model building for dynamic multi-tenant provider environments
Authors: Basak Jayanta , Wadhwani Kushal , Voruganti Kaladhar , Narayanamurthy Srinivasan , Mathur Vipul , Nandi Siddhartha
Published: January 2013

Increasingly, storage vendors are finding it difficult to leverage existing white-box and black-box modeling techniques to build robust system models that can predict system behavior in the emerging dynamic and multi-tenant data centers. White-box models are becoming brittle because the model builders are not able to keep up with the innovations in the storage system stack, and black-box models are becoming brittle because it is increasingly difficult to a priori train the model for the dynamic and multi-tenant data center environment. Thus, there is a need for innovation in system model building area.

In this paper we present a machine learning based blackbox modeling algorithm called M-LISP that can predict system behavior in untrained region for these emerging multitenant and dynamic data center environments. We have implemented and analyzed M-LISP in real environments and the initial results look very promising. We also provide a survey of some common machine learning algorithms and how they fare with respect to satisfying the modeling needs of the new data center environments.