bluuebunny/crossref_metadata_2025 huggingface dataset:
Physiological Effect on Different Reach Distances: A Case Study for Malaysia Adults
Authors: Dawal S.Z. , Sartika S.J. , Zadry H.R. , San Y. , Makhtar S.N. , Khyasudeen S.F.
Published: January 2013

The effects of oxygen uptake, heart rate and muscle activity while performing a repetitive lifting task in normal, maximum and extreme reach distances were investigated in the study. Ten subjects (5 females and 5 males) of age between 22-25 years were involved in the study. The results of oxygen uptake showed an increased of 11% and 39% from normal reach to maximum and extreme reach respectively. As for heart rate the results showed an increased of 8% and 17% from normal reach to maximum and extreme reach respectively. Electromyogram reading of anterior deltoid and upper trapezious muscles showed a tremendous increased of more than 80% while bicep brachii muscles showed an increase of only about 1 % from normal reach. The findings from the study showed an increased in the physiological responses when the work reach distance was increased. And lifting task, posture and load on this study developed back
pain.

Kesan pengambilan oksigen, kadar degupan jantung dan aktiviti otot ketika melaksanakan kerja mangangkat secara berulang pada kadar normal, maximum dan capaian melampau telah dikaji dalam kajian ini. Sepuluh orang peserta kajian, lima perempuan dan lima lelaki yang berumur antara 22-25 tahun terlibat dalam kajian ini. Keputusan kajian terhadap pengambilan oksigen menunjukkan kadar peningkatan sebanyak 11% dan 39% dari kadar normal untuk mencapai kadar maximum dan capaian melampau. Manakala untuk kadar degupan jantung keputusan menunjukkan peningkatan sebanyak 8% dan 17% dari keadaan normal untuk mencapai kadar maximum dan capaian melampau. Bacaan electromyogram pada anterior deltoid dan otot bahagian atas trapezious menunjukkan peningkatan yang besar iaitu sebanyak 80% manakala otot bicep brachii menunjukkan peningkatan sebanyak 1% sahaja dari keadaan normal. Penemuan dalam kajian ini menunjukkan peningkatan dalam tindak balas psikologikal apabila jarak capaian kerja meningkat. Dan pekerjaan mengangkat, postur dan beban dalam kajian ini mengakibatkan sakit belakang badan
Degradation of Water-based Mud Filter Cakes using Environmental Friendly Pullulanase Enzyme
Authors: Ismail Issham , Mahictin Masseera , Tan Siew Yan , Ali Rasol Azad Anugerah
Published: January 2013

TThe filter cake removal is of primary concern in a horizontal oil producer. It has been highlighted in many publications that the cleanup process in long horizontal and multilateral wells is a challenging task. Many chemical solutions have been used to remove the polymeric and bridging agents in oil producers. Due to their nonspecific characteristics, the chemical solutions have their limitations and in some cases have affected the well productivity. Thus an enzyme treatment using Pullulanase had been applied to degrade the mud filter cake of drill-in fluids, which comprised starch and xanthan gum. In this research work, static fluid loss and soaking tests were performed at temperatures ranging from 75°F to 250°F. The experimental results revealed that the efficiency of the cleaning solution comprising Pullulanase in degrading starch and xanthan gum was influenced by solution temperature and its concentration. For 6% concentration of Pullulanase, the highest degrading efficiencies experienced were 63%, 74%, 87%, 66% and 59% at temperatures of 75°F, 100°F, 150°F, 200°F, and 250°F respectively. In terms of concentration, it was found that 6% of Pullulanase gave the optimum efficiency as compared to 7% and 8% concentrations at temperature of 150°F. The experimental results also proved that enzyme stabilizer and viscoelastic surfactant could prevent the deactivation of enzyme activity at temperatures above 150 °F.

Penyingkiran kek turas menjadi perhatian utama dalam pengeluar mendatar minyak. Permasalahan ini telah diketengahkan dalam banyak penerbitan yang menyatakan bahawa proses pembersihan telaga mendatar yang panjang dan telaga berbilang sisi ialah suatu tugas yang mencabar. Pelbagai larutan kimia telah digunakan untuk menyingkir agen polimer dan agen penitian dalam pengeluar minyak. Berikutan ciri-cirinya yang tak khusus, larutan kimia mempunyai penggunaan yang terbatas dan dalam kes tertentu telah menjejaskan kebolehpengeluaran telaga. Sehubungan itu, rawatan enzim yang menggunakan Pullulanase telah diaplikasi untuk menurunkan kek turas bendalir gerudi yang mengandungi kanji dan gam xantan. Dalam penyelidikan ini, ujian kehilangan bendalir statik dan ujian rendaman telah dilaksanakan pada suhu yang berjulat dari 75°F hingga ke 250°F. Hasil kajian membuktikan bahawa kecekapan larutan pembersih yang mengandungi Pullulanase dalam menurunkan kanji dan gam xantan adalah dipengaruhi oleh suhu larutan dan kepekatannya. Untuk kepekatan 6% Pullulanase, kecekapan penurunan tertinggi yang dialami ialah 63%, 74%, 87%, 66%, dan 59% masing-masing pada suhu 75°F, 100°F, 150°F, 200°F, dan 250°F. Dari segi kepekatan, Pullulanase dengan kepekatan 6% telah memberikan kecekapan optimum yang lebih baik berbanding kepekatan 7% and 8% pada suhu 150 °F. Hasil kajian turut membuktikan bahawa penstabil enzim dan surfaktan likat-anjal berupaya mencegah daripada berlakunya penyahaktifan aktiviti enzim pada suhu yang melebihi 150°F.
Model Persamaan Struktural untuk Mengkaji Kesan Pengurusan Rantaian Pembekalan Hijau dalam Industri Pembuatan
Authors: Wan Mahmood Wan Hasrulnizzam , Ab Rahman Mohd Nizam , Md Deros Baba
Published: January 2013

Environmental issues such as pollution and the use of unrecyclable material are considered the global crises. As a result, green supply chain management (GSCM) was introduced as an alternative to the traditional approach of supply chain management (SCM) for environmental sustainability. This paper examines the impact of GSCM practices on the performance of: manufacturing, environment and economy by structural equation modelling. A total of 104 respondents were randomly selected from MS ISO 14001 manufacturing certified companies’ represent 43.15 percent of the population. . The variables and the relationships between variables in the structural equation model are determined via interview with 24 representatives from various companies. The structural equation modelling analysis confirmed that there is a positive correlation between the variables especially greening production and manufacturing performance, environmental performance, and economic performance; while manufacturing performance has significant influence on the environmental performance.

Isu alam sekitar seperti pencemaran dan penggunaan sumber yang tidak boleh dikitar semula menjadi permasalahan global. Justeru, pengurusan rantaian pembekalan hijau (GSCM) diperkenalkan sebagai alternatif kepada pendekatan tradisional pengurusan rantaian pembekalan (SCM) untuk melestarikan kepentingan alam sekitar. Kajian mengkaji kesan pengamalan GSCM ke atas prestasi: pembuatan, alam sekitar dan ekonomi melalui reka bentuk dan pengesahan model persamaan struktural. Seramai 104 responden dipilih secara rawak mewakili 43.15 peratus bilangan populasi syarikat pembuatan yang mendapat pengiktirafan MS ISO 14001. Ciri – ciri pemboleh ubah dan hubungan antara pemboleh ubah dalam model persamaan struktural ditentukan melalui temu bual dengan 24 wakil pengurusan di pelbagai syarikat. Analisis model persamaan struktural menunjukkan terdapat perhubungan yang signifikan di antara pemboleh ubah di mana elemen GSCM iaitu pengeluaran hijau dapat memberikan impak kepada prestasi pembuatan, prestasi alam sekitar dan prestasi ekonomi, termasuk prestasi pembuatan menunjukkan pengaruh signifikan terhadap prestasi alam sekitar.
Verification of an Old Conjecture on Nonabelian 2-generated Groups of Order p3
Authors: Barakat Yasamin , Sarmin Nor Haniza
Published: January 2013

A longstanding conjecture in group theory states: “Every finite non-abelian p-group possesses at least a non-inner automorphism of order”, where is a prime number. Recently, an updated classification of 2-generated p-groups of nilpotency class two has been published. Using this classification, we prove the verification of this conjecture for 2-generated groups of order.
A Study on Estimation of Propulsive Power for Wing in Ground Effect (WIG) Craft to Take-off
Authors: Priyanto A. , Maimun A. , Noverdo S. , Saeed J. , Faizal A. , Waqiyuddin M.
Published: January 2013

This paper estimated the propulsive power required for Wing in Ground effect (WIG) craft to take-off. The hull form design of the WIG craft incorporates a stepped planing triple hull, since the planing hull is well known to give result and assist in lifting off the water surface effect. In order to determine the power required for WIG craft to take-off, the craft prototype was built into 1 to 6 model scale. In numerical calculation, the required thrust motor of model to take-off was calculated by summation of water drag; aerodynamic drag and the weight of model. The water drag was estimated by Savitsky’s method, and the aerodynamic drag by a MATLAB programming based on Vortex Lattice Method (VLM). In the experiments, the relationship propeller RPM against thrust motor was obtained from the calibration tests. At the flight tests of the model, the propeller RPM of the model was measured to determine the total thrust motor and the propulsive power required to take-off by using the Froude’s Momentum Theory. The required propulsive power for craft scaled model was found to give the total thrusts of 33.85 N, and the effective power estimates required for WIG model to take-off per propeller was 128Watt at the design speed. It was also observed during most of the flight tests, the craft is attempting to enter into ground surface effect at design speed.

Kertas kerja ini mengira jumlah kuasa bagi bot Wing in Ground effect (WIG) untuk terbang. Perekabentuk bot WIG menggunakan badan bot planing, yang terkenal untuk membantu dan mengangkat badan bot ke atas permukaan air. Dalam mendapatkan kuasa bagi bot WIG untuk terbang, model bot dibina dalam skala 1 berbanding 6. Pengiraan kuasa bagi model WIG adalah pengiraan jumlah rintangan model pada setiap halaju, terhadap tambahan rintangan udara, rintangan air dengan jisim model. Kaedah yang digunakan dalam pengiraan jumlah rintangan model adalah dua kaedah iaitu kaedah berangka dan eksperimen. Dari kaedah berangka, rintangan air telah dikira menggunakan simulasi Savitsky, dan rintangan udara telah dikira menggunakan simulasi MATLAB berasaskan kaedah Vortex Lattice Method (VLM). Dari kaedah eksperimen, ujian kalibrasi dilakukan terlebih dahulu untuk mendapatkan hubungan antara RPM melawan daya dorong. Kemudian ujian terbang dilakukan untuk mendapatkan RPM untuk setiap halaju model sebelum terbang. Nilai RPM daripada ujian ini digunakan untuk mendapatkan jumlah daya dorong daripada ujian kalibrasi dan jumlah kuasa didapatkan dengan menggunakan persamaan hukum Froude’s Momentum. Keputusan jumlah daya dorong bagi model diperlukan untuk terbang daripada dua kaedah adalah 33.85 N, dan jumlah kuasa untuk satu kipas iaitu 128Watt. Daripada pengamatan ujian terbang, model WIG telah terbang dalam Ground Effect (GE) di atas permukaan air.
Coingestion of carbohydrate and protein during training reduces training stress and enhances subsequent exercise performance
Authors: Hall Andrew H. , Leveritt Michael D. , Ahuja Kiran D.K. , Shing Cecilia M.
Published: January 2013

Researchers have focused primarily on investigating the effects of coingesting carbohydrate (CHO) and protein (PRO) during recovery and, as such, there is limited research investigating the benefits of CHO+PRO coingestion during exercise for enhancing subsequent exercise performance. The aim of this study was to investigate whether coingestion of CHO+PRO during endurance training would enhance recovery and subsequent exercise performance. Ten well-trained male cyclists (aged 29.7 ± 7.5 years; maximal oxygen uptake, 66.2 ± 6 mL·kg−1·min−1) took part in a randomized, double-blind, cross-over trial. Each trial consisted of a 2.5-h morning training bout during which the cyclists ingested a CHO+PRO or energy-matched CHO beverage followed by a 4-h recovery period and a subsequent performance time trial (total work, 7 kJ·kg−1). Blood was collected before and after exercise. Time-trial performance was 1.8% faster in the CHO+PRO trial compared with the CHO trial (p = 0.149; 95% CI, −13 to 87 s; 75.8% likelihood of benefit). The increase in myoglobin level from before the training bout to after the training bout was lower in the CHO+PRO trial (0.74 nmol·L−1; 95% CI, 0.3–1.17 nmol·L−1) compared with the CHO trial (1.16 nmol·L−1; 95% CI, 0.6–1.71 nmol·L−1) (p = 0.018). Additionally, the decrease in neutrophil count over the recovery period was greater in the CHO+PRO trial (p = 0.034), and heart rate (p < 0.022) and rating of perceived exertion (RPE) (p < 0.01) were lower during training in the CHO+PRO trial compared with the CHO trial. Ingesting PRO, in addition to CHO, during strenuous training lowered exercise stress, as indicated by reduced heart rate, RPE, and muscle damage, when compared with CHO alone. CHO+PRO ingestion during training is also likely to enhance recovery, providing a worthwhile improvement in subsequent cycling time-trial performance.
Impacts of elevated temperature and CO2 with varying groundwater levels on seasonality of height and biomass growth of a boreal bioenergy crop (Phalaris arundinacea) — a modeling study
Authors: Zhang Chao , Kellomäki Seppo , Gong Jinnan , Wang Kaiyun , Ge Zhenming , Zhou Xiao , Strandman Harri
Published: January 2013

The boreal aquatic crop reed canary grass (Phalaris arundinacea L., hereafter RCG) is widely cultivated for bioenergy production in northern Europe, where climate change is likely to modify the growing conditions for this species substantially. In this context, we analyzed and modeled the effects of elevated temperature and CO2 together with variable groundwater levels on the seasonal development of height and the accumulation of the aboveground biomass in RCG. For this purpose, RCG plants were grown in autocontrolled environmental chambers over two growing seasons applying a factorial design, including two temperature regimes (ambient and ambient + approximately 3 °C), two carbon dioxide concentrations (ambient and approximately 700 μmol·mol−1), and three groundwater levels (0, 20, and 40 cm below the soil surface). The results showed that elevated temperature was the dominant variable controlling the seasonal course of height development and biomass accumulation, and soil water levels could accelerate or delay these processes. Compared with ambient conditions, elevated temperatures did not accelerate the onset of RCG but made growth cessation occur earlier. This made the growing period shorter and reduced final height and biomass accumulation than other climatic treatments. Elevated CO2 significantly increased height development and biomass accumulation throughout the growing period relative to ambient conditions, whereas no differences occurred regarding the onset, cessation, and duration of growing season. A higher groundwater level increased RCG growth, mainly because of the delay in the timing of the peak growth rate and of the cessation with prolonged duration of growing season compared with low groundwater level. However, the enhanced growth of RCG caused by elevated CO2 may be partly lost due to increasing temperature, which may reduce the availability of soil water and make senescence occur earlier. This will potentially inhibit the growth of RCG under drought conditions. Our results suggested that management of soil water and maintenance of high groundwater levels are key problems with respect to optimizing RCG biomass production under climate change in the boreal conditions.
A dispersion-corrected density functional theory study of hexamers of formic acid
Authors: McCarthy Shane P. , Roy Amlan K. , Kazachenko Sergey , Thakkar Ajit J.
Published: January 2013

Density functional theory with dispersion-correcting effective potentials is used to examine the low-lying isomers of the formic acid hexamer. The lowest-energy structure is a chairlike ring of six Z monomers. π-Stacked structures consisting of a dimer and tetramer lie higher in energy.
Thermal conductivity of bitumen concrete
Authors: Côté Jean , Grosjean Vivien , Konrad Jean-Marie
Published: January 2013

The thermal conductivity of bitumen concrete is a key parameter in the thermal analysis of pavements submitted to widely varying climate conditions. This paper presents the experimental results of thermal conductivity of bitumen concrete typically used in the Province of Quebec. The results show that the thermal conductivity of bitumen concrete is dependent on the aggregate's mineral origin and on the amount of air voids. It is also shown that the presence of bitumen increases thermal conductivity compared to unbound aggregates. The paper demonstrates that the effect of bitumen creates thermal bridges between aggregate particles similarly to other types of binders such as Portland cement and natural binders found in sedimentary rocks. Based on these observations and on the analyses of over 80 data sets from the literature, an existing model is used to develop a simplified thermal conductivity equation to estimate this parameter for bitumen concrete.
A randomized, double-blind, placebo-controlled trial of the effect of dried purple carrot on body mass, lipids, blood pressure, body composition, and inflammatory markers in overweight and obese adults: The QUENCH Trial
Authors: Wright Olivia R.L. , Netzel Gabriele A. , Sakzewski Amy R.
Published: January 2013

Obesity is a significant health issue worldwide and is associated with chronic, low-grade inflammation predisposing the individual to cardiovascular disease and impaired blood glucose homeostasis. Anthocyanins and phenolic acids from purple carrots are effective at reversing inflammation and metabolic alterations in animal models, potentially through inhibition of inflammatory pathways. The effects of dried purple carrot on body mass, body composition, blood pressure, lipids, inflammatory markers, liver function tests, and appetite were investigated in 16 males (aged 53.1 ± 7.6 years and with a mean BMI of 32.8 ± 4.6 kg/m2) with normal lipid and inflammatory markers. There was no evidence that 118.5 mg/day of anthocyanins and 259.2 mg/day of phenolic acids for 4 weeks resulted in statistically significant changes in body mass, body composition, appetite, dietary intake, low density lipoprotein, total cholesterol, blood pressure, or C-reactive protein in these obese participants at the dose and length of intervention used in this trial. High density lipoprotein cholesterol was lower in the intervention group (p < 0.05). Aspartate amino transferase and alanine amino transferase did not change, indicating that the intervention was safe. More studies are required to establish the bioavailability and pharmacokinetic effects of purple carrot anthocyanins and phenolic acids prior to further trials of efficacy with respect to treating inflammation and metabolic alterations.
Improving Municipal Information and Knowledge Management Capabilities: Case Study
Authors: Ekionea Jean-Pierre Booto , Fillion Gérard , Koffi Vivi
Published: January 2013

This study aims to better understand the process of knowledge management capabilities (KMC) development at the municipal context to assess its impact on organisational performance. This process is a part of the organisational learning school that promotes organisational learning processes and knowledge accumulation that could be spread over time and in different levels of maturity. Thus, using the KMC maturity model (KMCMM) which has five levels of maturity, this study helps to better understand the phenomenon of KMC in the municipal context.
Data Centres Operating in the Knowledge Economy
Authors: Laughton Paul
Published: January 2013

Data is an abundant resource in the knowledge economy and the need for data centres and storage solutions to harness this data is evident. This research attempts to gain an understanding of some of the practices amongst data centres participating in the knowledge economy. A mixed methods research approach was used to identify characteristics and practices of these data centres. This has led to the discovery of practices amongst these data centres that may not comply with the desired data practices in the knowledge economy. Based on these findings recommendations are made to improve data practices amongst data centres in the knowledge economy.
Intellectual Capital (IC) Measurement in the Mass Media Context
Authors: Pienaar Jaco
Published: January 2013

Mass media is the key influencer of public opinion. The influence is not only limited to political and social, but also relates to organisational and economical reputation and brands. Within public opinion, organisations must manage how they are represented competitively within mass media so that they can develop their brand strategically to grow and compete in the current global knowledge economy. This is where the link to Intellectual Capital (IC) Measurement is significant. IC, as the sum of all an organisation's intangible assets drives a company's presence and value within the media, albeit related to human, structural or relational capital attributes. The measurement, therefore, of IC in the mass media context is invaluable to understand how a company is placed strategically and competitively in the external space, and how this links to internal activities, goals and outcomes. This paper is an attempt to address some of the issues related to IC measurements in the mass media context by suggesting a framework that provides a multi-disciplinary and holistic approach to the understanding and contextualising of the organisation's presence in the public space.
Summarizing data succinctly with the most informative itemsets
Authors: Mampaey Michael , Vreeken Jilles , Tatti Nikolaj
Published: January 2013

Knowledge discovery from data is an inherently iterative process. That is, what we know about the data greatly determines our expectations, and therefore, what results we would find interesting and/or surprising. Given new knowledge about the data, our expectations will change. Hence, in order to avoid redundant results, knowledge discovery algorithms ideally should follow such an iterative updating procedure.

With this in mind, we introduce a well-founded approach for succinctly summarizing data with the most informative itemsets; using a probabilistic maximum entropy model, we iteratively find the itemset that provides us the most novel information—that is, for which the frequency in the data surprises us the most—and in turn we update our model accordingly. As we use the maximum entropy principle to obtain unbiased probabilistic models, and only include those itemsets that are most informative with regard to the current model, the summaries we construct are guaranteed to be both descriptive and nonredundant.

The algorithm that we present, called mtv, can either discover the top-
k
most informative itemsets, or we can employ either the Bayesian Information Criterion (bic) or the Minimum Description Length (mdl) principle to automatically identify the set of itemsets that together summarize the data well. In other words, our method will “tell you what you need to know” about the data. Importantly, it is a one-phase algorithm: rather than picking itemsets from a user-provided candidate set, itemsets and their supports are mined on-the-fly. To further its applicability, we provide an efficient method to compute the maximum entropy distribution using Quick Inclusion-Exclusion.

Experiments on our method, using synthetic, benchmark, and real data, show that the discovered summaries are succinct, and correctly identify the key patterns in the data. The models they form attain high likelihoods, and inspection shows that they summarize the data well with increasingly specific, yet nonredundant itemsets.
Substantial improvements in the set-covering projection classifier CHIRP (composite hypercubes on iterated random projections)
Authors: Wilkinson Leland , Anand Anushka , Dang Tuan Nhon
Published: January 2013

In Wilkinson et al. [2011] we introduced a new set-covering random projection classifier that achieved average error lower than that of other classifiers in the Weka platform. This classifier was based on anL∞norm distance function and exploited an iterative sequence of three stages (projecting, binning, and covering) to deal with the curse of dimensionality, computational complexity, and nonlinear separability. We now present substantial changes that improve robustness and reduce training and testing time by almost an order of magnitude without jeopardizing CHIRP's outstanding error performance.
WHAM
Authors: Li Yinan , Patel Jignesh M. , Terrell Allison
Published: January 2013

Over the last decade, the cost of producing genomic sequences has dropped dramatically due to the current so-called next-generation sequencing methods. However, these next-generation sequencing methods are critically dependent on fast and sophisticated data processing methods for aligning a set of query sequences to a reference genome using rich string matching models. The focus of this work is on the design, development and evaluation of a data processing system for this crucial “short read alignment” problem. Our system, called WHAM, employs hash-based indexing methods and bitwise operations for sequence alignments. It allows rich match models and it is significantly faster than the existing state-of-the-art methods. In addition, its relative speedup over the existing method is poised to increase in the future in which read sequence lengths will increase.
Wireless scheduling with power control
Authors: Halldórsson Magnús M.
Published: January 2013

We consider the scheduling of arbitrary wireless links in the physical model of interference to minimize the time for satisfying all requests. We study here the combined problem of scheduling and power control, where we seek both an assignment of power settings and a partition of the links so that each set satisfies the signal-to-interference-plus-noise (SINR) constraints.

We give an algorithm that attains an approximation ratio of
O
(log
n
ċ log log Δ), where
n
is the number of links and Δ is the ratio between the longest and the shortest link length. Under the natural assumption that lengths are represented in binary, this gives the first approximation ratio that is polylogarithmic in the size of the input. The algorithm has the desirable property of using an oblivious power assignment, where the power assigned to a sender depends only on the length of the link. We give evidence that this dependence on Δ is unavoidable, showing that any reasonably behaving oblivious power assignment results in a Ω(log log Δ)-approximation.

These results hold also for the (weighted) capacity problem of finding a maximum (weighted) subset of links that can be scheduled in a single time slot. In addition, we obtain improved approximation for a bidirectional variant of the scheduling problem, give partial answers to questions about the utility of graphs for modeling physical interference, and generalize the setting from the standard 2-dimensional Euclidean plane to doubling metrics. Finally, we explore the utility of graph models in capturing wireless interference.
Combinatiorial algorithms for wireless information flow
Authors: Ebrahimi Javad B. , Fragouli Christina
Published: January 2013

A long-standing open question in information theory is to characterize the unicast capacity of a wireless relay network. The difficulty arises due to the complex signal interactions induced in the network, since the wireless channel inherently broadcasts the signals and there is interference among transmissions. Recently, Avestimehr et al. [2007b] proposed a linear deterministic model that takes into account the shared nature of wireless channels, focusing on the signal interactions rather than the background noise. They generalized the min-cut max-flow theorem for graphs to networks of deterministic channels and proved that the capacity can be achieved using information theoretical tools. They showed that the value of the minimum cut is in this case the minimum rank of all the adjacency matrices describing source-destination cuts.

In this article, we develop a polynomial-time algorithm that discovers the relay encoding strategy to achieve the min-cut value in linear deterministic (wireless) networks, for the case of a unicast connection. Our algorithm crucially uses a notion of linear independence between channels to calculate the capacity in polynomial time. Moreover, we can achieve the capacity by using very simple one-symbol processing at the intermediate nodes, thereby constructively yielding finite-length strategies that achieve the unicast capacity of the linear deterministic (wireless) relay network.
On the set multicover problem in geometric settings
Authors: Chekuri Chandra , Clarkson Kenneth L. , Har-Peled Sariel
Published: January 2013

We consider the set multicover problem in geometric settings. Given a set of points P and a collection of geometric shapes (or sets)
F
, we wish to find a minimum cardinality subset of
F
such that each point p ∈ P is covered by (contained in) at least d(p) sets. Here, d(p) is an integer demand (requirement) for p. When the demands d(p) = 1 for all p, this is the standard set cover problem. The set cover problem in geometric settings admits an approximation ratio that is better than that for the general version. In this article, we show that similar improvements can be obtained for the multicover problem as well. In particular, we obtain an
O
(log opt) approximation for set systems of bounded VC-dimension, and an
O
(1) approximation for covering points by half-spaces in three dimensions and for some other classes of shapes.
Approximating parameterized convex optimization problems
Authors: Giesen Joachim , Jaggi Martin , Laue Sören
Published: January 2013

We consider parameterized convex optimization problems over the unit simplex, that depend on one parameter. We provide a simple and efficient scheme for maintaining an ϵ-approximate solution (and a corresponding ϵ-coreset) along the entire parameter path. We prove correctness and optimality of the method. Practically relevant instances of the abstract parameterized optimization problem are for example regularization paths of support vector machines, multiple kernel learning, and minimum enclosing balls of moving points.
On exact algorithms for treewidth
Authors: Bodlaender Hans L. , Fomin Fedor V. , Koster Arie M. C. A. , Kratsch Dieter , Thilikos Dimitrios M.
Published: January 2013

We give experimental and theoretical results on the problem of computing the treewidth of a graph by exact exponential-time algorithms using exponential space or using only polynomial space. We first report on an implementation of a dynamic programming algorithm for computing the treewidth of a graph with running time
O
*(2

n

). This algorithm is based on the old dynamic programming method introduced by Held and Karp for the Traveling Salesman problem. We use some optimizations that do not affect the worst case running time but improve on the running time on actual instances and can be seen to be practical for small instances. We also consider the problem of computing Treewidth under the restriction that the space used is only polynomial and give a simple
O
*(4

n

) algorithm that requires
polynomial
space. We also show that with a more complicated algorithm using balanced separators, Treewidth can be computed in
O
*(2.9512

n

) time and polynomial space.
Cycle detection and correction
Authors: Amir Amihood , Eisenberg Estrella , Levy Avivit , Porat Ely , Shapira Natalie
Published: January 2013

Assume that a natural cyclic phenomenon has been measured, but the data is corrupted by errors. The type of corruption is application-dependent and may be caused by measurements errors, or natural features of the phenomenon. We assume that an appropriate metric exists, which measures the amount of corruption experienced. This article studies the problem of recovering the correct cycle from data corrupted by various error models, formally defined as the
period recovery problem
. Specifically, we define a metric property which we call
pseudolocality
and study the period recovery problem under pseudolocal metrics. Examples of pseudolocal metrics are the Hamming distance, the swap distance, and the interchange (or Cayley) distance. We show that for pseudolocal metrics, periodicity is a powerful property allowing detecting the original cycle and correcting the data, under suitable conditions. Some surprising features of our algorithm are that we can efficiently identify the period in the corrupted data, up to a number of possibilities logarithmic in the length of the data string, even for metrics whose calculation is
NP-hard
. For the Hamming metric, we can reconstruct the corrupted data in near-linear time even for unbounded alphabets. This result is achieved using the property of separation in the self-convolution vector and Reed-Solomon codes. Finally, we employ our techniques beyond the scope of pseudo-local metrics and give a recovery algorithm for the non-pseudolocal Levenshtein edit metric.
Browser security
Authors: CACM Staff
Published: January 2013

A discussion with Jeremiah Grossman, Ben Livshits, Rebecca Bace, and George Neville-Neil
Ubiquity symposium: Evolutionary computation and the processes of life
Authors: Sipper Moshe
Published: January 2013

In this article, Moshe Sipper discusses a foreseeable future in which an entirely new paradigm of producing software will emerge. Sipper calls this software engineering revolution, "Darwinian Software Engineering"---a time when it will be possible to program computers by means of evolution.
The Creativity Killers At Work
Authors: Grant Andrew , Grant Gaia
Published: January 2013

Is your team creative? Perhaps you need to cultivate an environment that allows positive ideas to flow.
Gamification: The Latest Buzzword and the Next Fad
Authors: Boulet Guy
Published: January 2013

The term gamification seems to be the latest buzzword in the learning realm. The term describing the use of game mechanics in non-game contexts, has rapidly been hijacked by the industry as a marketing term. In a field where buzzwords seem to define the latest approaches, can we expect gamification to deliver the miracles the industry promises. When we look at the previous learning fads that were — Virtual Environments' and “Web 2.0” we can sincerely doubt it.
Algorithms column
Authors: Khuller Samir
Published: January 2013

The exponent ω of matrix multiplication is the infimum over all real numbers
c
such that for all ε > 0 there is an algorithm that multiplies
n - n
matrices using at most O(
n
c+ε
) arithmetic operations over an arbitrary field. A trivial lower bound on ω is 2, and the best known upper bound until recently was ω < 2.376 achieved by Coppersmith and Winograd in 1987. There were two independent improvements on ω, one by Stothers in 2010 who showed that ω < 2.374, and one by myself that ultimately resulted in ω < 2.373. Here I discuss the road to these improvements and conclude with some open questions.
Systems research and innovation in data ONTAP
Authors: Dawkins Scott , Voruganti Kaladhar , Strunk John D.
Published: January 2013

Over the last 20 years, there have been many changes in the data storage industry. NetApp® products have kept pace and pushed the boundary in various areas. Staying at the forefront requires attentiveness to emerging technology trends and a disciplined approach to analyzing them. By understanding the trends and how they affect our customers, we can focus our efforts on delivering the best products possible. In this issue of OSR, we highlight some of the research and innovation that have helped us stay at the forefront of these technological changes.
RAID triple parity
Authors: Goel Atul , Corbett Peter
Published: January 2013

RAID triple parity (RTP) is a new algorithm for protecting against three-disk failures. It is an extension of the double failure correction Row-Diagonal Parity code. For any number of data disks, RTP uses only three parity disks. This is optimal with respect to the amount of redundant information required and accessed. RTP uses XOR operations and stores all data un-encoded. The algorithm's parity computation complexity is provably optimal. The decoding complexity is also much lower than that of existing comparable codes. This paper also describes a symmetric variant of the algorithm where parity computation is identical to triple reconstruction.
Lockless multi-core high-throughput buffering scheme for kernel tracing
Authors: Desnoyers Mathieu , Dagenais Michel R.
Published: January 2013

Studying execution of concurrent real-time online systems, to identify far-reaching and hard to reproduce latency and performance problems, requires a mechanism able to cope with voluminous information extracted from execution traces. Furthermore, the workload must not be disturbed by tracing, thereby causing the problematic behavior to become unreproducible.

In order to satisfy this low-disturbance constraint, we created the LTTng kernel tracer. It is designed to enable safe and race-free attachment of probes virtually anywhere in the operating system, including sites executed in non-maskable interrupt context.

In addition to being reentrant with respect to all kernel execution contexts, LTTng offers good performance and scalability, mainly due to its use of per-CPU data structures, local atomic operations as main buffer synchronization primitive, and RCU (Read-Copy Update) mechanism to control tracing.

Given that kernel infrastructure used by the tracer could lead to infinite recursion if traced, and typically requires non-atomic synchronization, this paper proposes an asynchronous mechanism to inform the kernel that a buffer is ready to read. This ensures that tracing sites do not require any kernel primitive, and therefore protects from infinite recursion.

This paper presents the core of LTTng's buffering algorithms and measures its performance.
Salton award lecture information retrieval as engineering science
Authors: Fuhr Norbert
Published: January 2013

This paper gives my personal view on the field of information retrieval (IR), by first presenting my own definition of the field, and then pointing out why IR isn't an engineering science yet. For the latter, IR lacks appropriate theoretic foundations, which would not only give us a better understanding of current systems, but also would provide a generally valid basis for building systems, and enable us to make predictons about the performance of these systems. For reaching this goal, we need a well-balanced interplay between theory building, hypothesis generation and testing via experimentation.
Synthesis of Nanosized Zinc‐Doped Cobalt Oxyhydroxide Parties by a Dropping Method and Their Carbon Monoxide Gas Sensing Properties
Authors: Wang Jian-Wen , Kuo Yi-Ming
Published: January 2013

Two nanostructures of cobalt oxyhydroxide (CoOOH) and Zinc‐(Zn‐) doped CoOOH (1–4% Zn) are prepared from Co(NO3)2 solution via microtitration with NaOH and oxidation in air. The X‐ray diffraction (XRD) analysis results show that a pure state of nano‐CoOOH can be obtained at an alkalinity (OH−/Co+) of 5 with 40°C heat treatment after 6 h. The Zn ions preferentially substitute Co ions in the CoOOH structure, resulting in a decrease of its crystallinity. The disc‐like CoOOH nanostructure exhibits good sensitivity to carbon monoxide (CO) in a temperature range of 40–110°C with maximum sensitivity to CO at around 70–80°C. When CoOOH nanostructure is doped with 1% Zn, its sensitivity and selectivity for CO gas are improved at 70–80°C; further Zn doping to 2% degraded the CO sensing properties of nano‐CoOOH. The results of a cross‐sensitivity investigation of the sensor to various gases coexisting at early stages of a fire show that the sensitivity of Zn‐doped nano‐CoOOH is the highest toward CO. Zn‐doped nano‐CoOOH film exhibits a high sensitivity to CO at room temperature, making it a promising sensor for early‐stage fire detection.
Skin-Sparing Mastectomy with Immediate Breast and Nipple Reconstruction: A New Technique of Nipple Reconstruction
Authors: Serra Raffaele , Miglietta Anna Maria , Abonante Sergio , Giordano Vincent , Buffone Gianluca , de Franciscis Stefano
Published: January 2013

Background. Most women with breast cancer today can be managed with breast conservation; however, some women still require mastectomy for treatment of their disease. Skin-sparing mastectomy (SSM) with immediate reconstruction has emerged as a favorable option for many of these patients. The authors combined the SSM technique with the preservation of a small part of the areola with immediate nipple together with with breast reconstruction. Methods. In an 8-year-period 155 female patients (age: 20–52 years old; mean age: 37.5 years) with extensive ductal intraepithelial neoplasia (DIN) or invasive breast cancer were treated with areola skin sparing mastectomy with immediate nipple and breast reconstruction. Patients were followed up prospectively by the breast surgeon, the plastic surgeon, and the oncologist for complications and recurrence. Results. After treatment, only 2 cases (1.29%) had a local recurrence. 8 out of 155 (5.5%) patients developed early complications (infections, seroma, haematoma), and 5 out of 155 patients (3.22%) developed delayed complications (implant rotation, aestethic deterioration) in the post operative time period. The final aesthetic outcome was judged as positive in 150 out of 155 patients (96.78%). Conclusion. In our experience, immediate nipple reconstruction after skin-sparing mastectomy is a technically feasible procedure which can give excellent cosmetic results.
Agenesis of Isthmus of the Thyroid Gland in a Patient with Graves-Basedow Disease and a Solitary Nodule
Authors: Ozkan Omer Faruk , Asık Mehmet , Toman Huseyin , Ozkul Faruk , Cıkman Oztekin , Karaayvaz Muammer
Published: January 2013

The thyroid is a vascular endocrine gland with two lateral lobes connected by a narrow, median isthmus. Although a wide range of congenital anomalies of the thyroid gland has been reported in the literature, agenesis of the thyroid isthmus is a very rare congenital anomaly. Thyroid isthmus agenesis does not manifest clinical symptoms, and it can be confused with other thyroid pathologies. We describe a patient with no isthmus of the thyroid, associated with Graves-Basedow disease. Thyroid isthmus agenesis should be kept in mind in order for surgical procedures involving thyroid pathologies to be carried out safely.
Low Circulating Protein C Levels Are Associated with Lower Leg Ulcers in Patients with Diabetes
Authors: Whitmont K. , Fulcher G. , Reid I. , Xue M. , McKelvey K. , Xie Y. , Aboud M. , Ward C. , Smith M. M. , Cooper A. , March L. , Jackson C. J.
Published: January 2013

Activated protein C (APC) promotes angiogenesis and reepithelialisation and accelerates healing of diabetic ulcers. The aim of this study was to determine the relationship between the incidence of lower leg ulcers and plasma levels of APC's precursor, protein C (PC), in diabetic patients. Patients with diabetes who had a lower leg ulcer(s) for >6 months (n=36) were compared with age-, type of diabetes-, and sex-matched subjects with diabetes but without an ulcer (n=36, controls). Total PC was assessed using a routine PC colorimetric assay. There was a significantly (P<0.001) lower level of plasma PC in patients with ulcers (103.3 ± 22.7, mean ± SD) compared with control (127.1±34.0) subjects, when corrected for age and matched for gender and type of diabetes. Ulcer type (neuropathic, ischaemic, or mixed) was not a significant covariate for plasma PC levels (P=0.35). There was no correlation between PC levels and gender, type of diabetes,HbA1c, or C-reactive protein in either group. In summary, decreased circulating PC levels are associated with, and may predispose to, lower leg ulceration in patients with diabetes.
The Development of Conductive Nanoporous Chitosan Polymer Membrane for Selective Transport of Charged Molecules
Authors: Chen Pei-Ru , Chuang Yun-Ju
Published: January 2013

We present the development of conductive nanoporous CNT/chitosan membrane for charge‐selective transport of charged molecules, carboxylfluorescein (CF), substance P, and tumor necrosis factor‐alpha (TNF‐α). The membrane was made porous and conductive via gelatin nanoparticle leaching technique and addition of carbon nanotubes, respectively. These nanoporous membranes discriminate the diffusion of positive‐charged molecules while inhibiting the passage of negative‐charged molecules as positive potential was applied. The permeation selectivity of these membranes is reversed by converting the polarity of applied potential into negative. Based on this principle, charged molecules (carboxylfluorescein, substance P, and TNF‐α) are successfully filtered through these membranes. This system shows 30 times more selective for CF than substance P as positive potential was applied, while 2.5 times more selective for substance P than CF as negative potential was applied.
Reducing Carbon-Based Energy Consumption through Changes in Household Behavior
Authors: Dietz Thomas , Stern Paul C. , Weber Elke U.
Published: January 2013

Actions by individuals and households to reduce carbon-based energy consumption have the potential to change the picture of U.S. energy consumption and carbon dioxide emissions in the near term. To tap this potential, however, energy policies and programs need to replace outmoded assumptions about what drives human behavior; they must integrate insights from the behavioral and social sciences with those from engineering and economics. This integrated approach has thus far only occasionally been implemented. This essay summarizes knowledge from the social sciences and from highly successful energy programs to show what the potential is and how it can be achieved.
The Public Acceptance of New Energy Technologies
Authors: Kasperson Roger E. , Ram Bonnie J.
Published: January 2013

In the wake of ominous results about the impending path of climate change, and with gasoline prices hovering around four dollars per gallon, the 2012 presidential and congressional campaigns are full of claims and counterclaims about the transformation of the U.S. energy system. Although much discussion has centered on the need for new energy technologies, this debate as yet has been narrow and limited. Meaningful deployment of any technology will raise questions of public acceptance. Little is known about how diverse publics in the United States will respond to the advent of new energy sources, whether they involve a “second renaissance” for nuclear power, a dash to embrace hydraulic fracking for oil and natural gas, or emerging prospects for renewable energies like wind and solar power. Yet public acceptance will determine the outlook. Adding further complication is the growing debate about traditional energy sources and the extent to which a fossil fuel – based energy system should continue to be central to the American economy. This essay explores the issues involved in public acceptance of stability and change in the U.S. energy system. We conclude with several recommendations for gaining a greater understanding of the public acceptance quandary.