bluuebunny/crossref_metadata_2025 huggingface dataset:
A clinical report demonstrating the significance of distinguishing a nasopalatine duct cyst from a radicular cyst
Authors: Aparna Manikkath , Chakravarthy Arumugam , Acharya Shashi Rashmi , Radhakrishnan Raghu
Published: March 2014

Endodontic diagnosis is challenging and depends on the organisation of information from the patient history, clinical examination and analysis of the pulp, radiographic and histopathological assessment. A 35-year-old man was endodontically treated for radiolucency in relation to the roots of maxillary central incisors as it was a provisionally diagnosed case of radicular cyst. Since the palatal swelling persisted, the lesion was re-evaluated using relevant diagnostic aids and a diagnosis of nasopalatine duct cyst (NPDC) was made, which was missed during the initial assessment. An erroneous interpretation of cystic radiolucency in relation to maxillary central incisors can often lead to inappropriate treatment planning. This case highlights the relevant aspects in the diagnosis of NPDC when it is mistaken for a radicular cyst and emphasises the need for thorough clinical examination and relevant investigations for periapical radiolucencies of questionable origin before initiating endodontic therapy.
Intraparenchymal haemorrhage and uncal herniation resulting from dobutamine stress echocardiography
Authors: Bennin Charles-Lwanga Kobina , Ramoutar Virin , Velarde Gladys
Published: March 2014

Intracranial haemorrhage (ICH) resulting from dobutamine stress echocardiography (DSE) is a rare complication in an otherwise relatively safe procedure. There has been one previously reported case of ICH associated with DSE in a patient who was fully anticoagulated. The authors report a second case of ICH associated with DSE leading to a poor outcome. Unlike the previous report, this patient was not fully anticoagulated and bleeding resulted from uncontrolled hypertension. Clinicians should be attentive to the risk of ICH associated with DSE in the setting of uncontrolled hypertension.
Phlyctenular conjunctivitis: a rare association with spinal intramedullary tuberculoma
Authors: Bhandari Aveg , Bhandari Heena , Shukla Rakesh , Giri Prithvi
Published: March 2014

We present a case of a 33-year-old woman who presented with phlyctenular conjunctivitis while on treatment for spinal intramedullary tuberculosis. She was treated with topical steroids along with continuation of antitubercular therapy, and improved on this treatment.
Lifelong exposure to n-3 PUFA affects pubertal mammary gland development
Authors: Anderson Breanne M. , MacLennan Mira B. , Hillyer Lyn M. , Ma David W.L.
Published: March 2014

There is growing evidence that early developmental periods may importantly influence future breast cancer risk. Also, there is great interest in the role of dietary fat in breast cancer risk, but the role of dietary fat during pubertal mammary gland development remains poorly understood. This study investigated the effect of n-3 polyunsaturated fatty acids (PUFA) using complementary dietary and genetic approaches to examine the effect of lifelong exposure of n-3 PUFA or n-6 PUFA (control) on mammary gland development and fatty acid composition. n-3 PUFA from both diet and genetics were enriched in mammary glands as early as 3 weeks of age. Parameters related to mammary gland development, including number of terminal end buds (TEB), percent coverage of ductal tree, and infiltration of TEB, were influenced by n-3 PUFA at 3 and 4 weeks of age. Overall, findings suggest that n-3 PUFA incorporation into the mammary gland early in life plays a role in the morphological development of the mammary gland during puberty.
The ISSMGE Kerry Rowe Lecture: The role of diffusion in environmental geotechnics
Authors: Shackelford Charles D.
Published: March 2014

Diffusion of contaminants can play a significant if not dominant role in many applications encountered within the field of environmental geotechnics. The objective of this paper is to provide an overview of the important role diffusion plays in such applications. The presentation proceeds from a historical perspective, beginning with the recognition in the late 1970s to early 1980s that diffusion may be an important process in assessing contaminant migration through low-permeability barriers in waste containment applications. Data from the literature and simplified model simulations are used to illustrate under what conditions diffusion is important, and the significance of diffusion is illustrated with respect to different barrier components and types of barriers used in waste containment applications. The barriers considered include natural clays, compacted clay liners, geomembranes, geosynthetic clay liners, composite liners, vertical cutoff walls, subaqueous caps for contaminated sediments, and highly compacted bentonite buffers for high-level radioactive waste containment. The significance of semi-permeable membrane behavior on liquid-phase diffusion through bentonite-based barriers also is highlighted. The potential importance of matrix diffusion as an attenuation mechanism for contaminant transport is illustrated, and the roles of both liquid-phase and gas-phase diffusion under unsaturated conditions are discussed. Finally, the role of diffusion in terms of remediation applications is illustrated via an example analysis illustrating the impact of reverse matrix or back diffusion on the effectiveness of pump-and-treat remediation, as well as via a summary of several diffusion-based models commonly used to describe the leaching of contaminants from a variety of stabilized–solidified waste forms.
Comparative resource-use efficiencies and growth ofPopulus trichocarpaandPopulus balsamiferaunder glasshouse conditions
Authors: Pointeau Virginie M. , Guy Robert D.
Published: March 2014

Amongst other traits, ideal poplar genotypes for afforestation programs would be fast growing and have high resource-use efficiencies. Black cottonwood (Populus trichocarpa Torr. & A. Gray) and balsam poplar (Populus balsamifera L.) are closely related species that together extend over much of the forested area of Canada. Within their respective ranges, however, black cottonwood attains much greater size than balsam poplar. Two populations of each species, each with three replicates of 9–10 genotypes, were grown from stem cuttings for 60 days in a greenhouse under long days to examine variation in biomass, height growth, net photosynthesis (A), stomatal conductance (gs), intrinsic water-use efficiency (A/gs), photosynthetic nitrogen-use efficiency (PNUE), leaf and stemwood13C/12C isotope ratios (δ13C), stomatal density (Ds), and leaf amphistomaticity. There were no significant differences in A, PNUE, biomass, or height growth between species. On average, black cottonwood had lower gsand Ds, but higher A/gsand δ13C. Variation within provenances, in most traits, exceeded variation between species or provenances. δ13C and A/gswere highly correlated across all genotypes. Variation in A/gsseemed primarily related to gs, although positive correlations were found between δ13C and A in the P. balsamifera populations, which more generally met expectations for sink-driven differences in water-use efficiency. There is potential to identify fast-growing genotypes with relatively high use efficiencies for both water and nitrogen.
A wall-crossing formula for degrees of Real central projections
Authors: Okonek Christian , Teleman Andrei
Published: March 2014

The main result is a wall-crossing formula for central projections defined on submanifolds of a Real projective space. Our formula gives the jump of the degree of such a projection when the center of the projection varies. The fact that the degree depends on the projection is a new phenomenon, specific to Real algebraic geometry. We illustrate this phenomenon in many interesting situations. The crucial assumption on the class of maps we consider is relative orientability, a condition which allows us to define a ℤ-valued degree map in a coherent way. We end the article with several examples, e.g. the pole placement map associated with a quotient, the Wronski map, and a new version of the Real subspace problem.
Proper holomorphic mappings between hyperbolic product manifolds
Authors: Janardhanan Jaikrishnan
Published: March 2014

We prove a result on the structure of finite proper holomorphic mappings between complex manifolds that are products of hyperbolic Riemann surfaces. While an important special case of our result follows from the ideas developed by Remmert and Stein, the proof of the full result relies on the interplay of the latter ideas and a finiteness theorem for Riemann surfaces.
Diffusion and dissipation by linear momentum in spherical environment
Authors: Scheid Werner , Isar Aurelian , Sandulescu Aurel
Published: March 2014

An open quantum system is studied consisting of a particle moving in a spherical space with an infinite wall. With the theory of Lindblad the system is described by a density matrix which gets affected by operators with diffusive and dissipative properties depending on the linear momentum and density matrix only. It is shown that an infinite number of basis states leads to an infinite energy because of the infinite unsteadiness of the potential energy at the infinite wall. Therefore only a solution with a finite number of basis states can be performed. A slight approximation is introduced into the equation of motion in order that the trace of the density matrix remains constant in time. The equation of motion is solved by the method of searching eigenvalues. As a side-product two sums over the zeros of spherical Bessel functions are found.
SUSPICIOUS REGION DETECTION AND IDENTIFICATION BASED ON INTRA-/INTER-FRAME ANALYSES AND FUZZY CLASSIFIER FOR BREAST MAGNETIC RESONANCE IMAGING
Authors: LIN GUO-SHIANG , CHAI SIN-KUO , YEH WEI-CHENG , LIN YI-CHANG
Published: March 2014

Breast cancer is one of the leading causes of death from cancer in Taiwan. In this paper, we propose a feature-based scheme composed of preprocessing, feature extraction and a fuzzy classifier for suspicious region detection and identification. In the preprocessing stage, we first extract regions of interest and then coarsely determine suspicious regions via candidate screening. Some features are extracted based on intra-slice, texture and inter-slice analysis techniques for suspicious region identification. Intra-slice analysis evaluates the intensity and size of suspicious regions. To find a precise region, we propose a region growing algorithm based on ellipse-based approximation. In texture analysis, some texture cues are extracted from spatial and wavelet domains and integrated as a combined texture feature by using a neural network. Inter-slice analysis is based on the continuity characteristic and consistency of a suspicious region's size; the objective is to verify the static behavior of suspicious regions. Several magnetic resonance imaging (MRI) cases are utilized to evaluate the performance of the proposed scheme. Experimental results demonstrate that our scheme can not only extract regions of interest but also identify tumors well from magnetic resonance images.
COMPARISON BETWEEN CAST IMMOBILIZATION VERSUS VOLAR LOCKING PLATE FIXATION OF DISTAL RADIUS FRACTURES IN ACTIVE ELDERLY PATIENTS, THE ASIAN PERSPECTIVE
Authors: Chan Ying-Ho , Foo Tun-Lin , Yeo Chong-Jin , Chew Winston Yoon-Chong
Published: March 2014

Displaced distal radius fractures in active elderly patients with high functional demand present a clinical dilemma because current evidence is equivocal in the recommendation of treatment. Internal fixation is an increasingly popular option with proposed superior results. Our study aims to evaluate the results among a population of active elderly patients with displaced fractures managed with either cast immobilization or internal fixation with volar locking plate.

Seventy-five patients (35 cast immobilization and 40 internal fixation) with mean age of 74 ± 7.5 years with minimum of 12 months follow-up were studied. The radiological and clinical parameters were assessed at three, six, and 12 months. Functional outcomes (DASH, Green-O'Brien) were assessed at 12 months. Patients who underwent surgery regain wrist motion and grip strength earlier, but this was not statistically significant after six months.
PROXIMAL ULNAR STUMP STABILITY AFTER USING THE PRONATOR QUADRATUS MUSCLE TRANSFER COMBINED WITH THE SUAVÉ-KAPANDJI PROCEDURE IN RHEUMATOID WRIST
Authors: Uerpairojkit Chairoj , Leechavengvongs Somsak , Malungpaishorpe Kanchai , Witoonchart Kiat , Buddhavibul Panai
Published: March 2014

The pronator quadratus muscle transfer combined with the Sauvé-Kapandji procedure was used to treat the distal radioulnar joint disorder in ten rheumatoid wrists for prevention against instability of the proximal ulnar stump. All patients were female with a mean age of 46.6 years. The mean follow-up time was 24.2 months. Postoperatively, supination increased in all patients with a mean of 50 degrees. Pain decreased significantly and none complained of prominence of the proximal ulnar stump in normal pronated position and during a tight grip. The wrist radiographs of both coronal and sagittal planes in normal and stress fisting views were used to evaluate the postoperative static and physiologic loaded stability of the proximal ulnar stump. It had shown this procedure provided good static proximal ulnar stump stability in both coronal and sagittal planes. However, in physiologic loaded condition, it was able to provide stability only in the sagittal plane.
SIMPLE SURGERY TO IMPROVE FLEXION DEFICIT RESULTING FROM MAL-UNION OF FRACTURE NECK OF THE PROXIMAL PHALANX — A CASE REPORT
Authors: Kang Yong Chiang , Tan Puay Ling
Published: March 2014

Mal-union of the proximal phalanx can result in stiffness and decreased grip strength. Corrective osteotomy is precarious, especially for mal-union of the neck, as complications like non-union and avascular necrosis may occur. We describe a simple technique of subcondylar fossa reconstruction for mal-union of the proximal phalanx to overcome these problems.
1/f NOISE IN ISING QUANTUM COMPUTERS
Authors: YE BIN , QIU LIANG
Published: March 2014

We study the 1/fα-phenomenon in one- and two-dimensional spin-1/2 lattice models, which have been proposed for realizing scalable quantum computers. Taking the eigenvalue spectrum of the Hamiltonian for the quantum spin model as a discrete-time series, the Fourier power spectrum for the fluctuations in it is analyzed in terms of its frequency. A 1/fα type power-law behavior is observed in both spin models. As the nearest-neighbor interaction strength between the qubits increases, the exponent α across a transition from α = 2 to α = 1.
Pullback attractors for a damped wave equation with delays
Authors: Wang Yejuan
Published: March 2014

Using a method to prove the pullback asymptotically compactness for the multi-valued processes, we present the existence of unique pullback attractors in CV,H and CD(A),V for the multi-valued process associated with a damped wave equation with delays and without the uniqueness of solutions.
Symmetry classes of polynomials associated to the semidihedral group and o-bases
Authors: Rodtes Kijti
Published: March 2014

In this paper, we discuss the existence of o-basis of the symmetry classes of polynomials associated to the irreducible characters of the semidihedral groups.
Finite semigroups that are minimal for not being Malcev nilpotent
Authors: Jespers E. , Shahzamanian M. H.
Published: March 2014

We give a description of finite semigroups S that are minimal for not being Malcev nilpotent, i.e. every proper subsemigroup and every proper Rees factor semigroup is Malcev nilpotent but S is not. For groups this question was considered by Schmidt.
Σ-semi-compact rings and modules
Authors: Behboodi Mahmood , Couchot Francois , Shojaee Seyed Hossein
Published: March 2014

In this paper, several characterizations of semi-compact modules are given. Among other results, we study rings whose semi-compact modules are injective. We introduce the property Σ-semi-compact for modules and we characterize the modules satisfying this property. In particular, we show that a ring R is left Σ-semi-compact if and only if R satisfies the ascending (respectively, descending) chain condition on the left (respectively, right) annulets. Moreover, we prove that every flat left R-module is semi-compact if and only if R is left Σ-semi-compact. We also show that a ring R is left Noetherian if and only if every pure projective left R-module is semi-compact. Finally, we consider rings whose flat modules are finitely (singly) projective. For any commutative arithmetical ring R with quotient ring Q, we prove that every flat R-module is semi-compact if and only if every flat R-module is finitely (singly) projective if and only if Q is pure semisimple. A similar result is obtained for reduced commutative rings R with the space Min R compact. We also prove that every (ℵ0, 1)-flat left R-module is singly projective if R is left Σ-semi-compact, and the converse holds if Rℕis an (ℵ0, 1)-flat left R-module.
Oriented Steiner quasigroups
Authors: Stuhl Izabella
Published: March 2014

We introduce the notion of an oriented Steiner quasigroup and develop elements of a relevant algebraic apparatus. The approach is based upon (modified) Schreier-type f-extensions for quasigroups (cf. earlier works [10, 11, 14]) achieved through oriented Steiner triple systems. This is done in a fashion similar to one in [13] where an analogous construction was established for loops. As a justification of this concept we briefly discuss an application of oriented Steiner triple systems in cryptography using oriented Steiner quasigroups.
A DESIGN FOR A SUSTAINABLE ELECTRICAL POWER SYSTEM
Authors: STEFANOV S. Z. , WANG PAUL P.
Published: March 2014

A sustainable electric power system (EPS) is designed in this paper. First, a protocol is given, via which Maxwell's demon transfers green energy into optimally secure and efficient EPS. Then a morphogenesis scheme (design) of a homeostatic demon is determined, so that the demon can achieve sustainable EPS stability. It is shown that synchronization protocol complicates the sustainable EPS and that the beneficial design transforms the sustainable EPS in a complex community. A sustainability test is introduced for the sake of coping with the issue in the sense the test serves to determine the EPS is indeed sustainable.
Lithospheric flexure and volcano basal boundary conditions: keys to the structural evolution of large volcanic edifices on the terrestrial planets
Authors: McGovern Patrick J. , Grosfils Eric B. , Galgana Gerald A. , Morgan Julia K. , Rumpf M. Elise , Smith John R. , Zimbelman James R.
Published: March 2014

Large volcanic edifices constitute enormous loads at the surfaces of planets. The lithosphere, the mechanically strong outer layer of a planet, responds to growing edifice loads by flexing. The shape of this lithospheric flexure and the resulting stress state exert critical influences on the structure of the evolving edifices, which in turn feed back into the flexural response. Flexural subsidence of the lithosphere forms topographical moats surrounding volcanoes that are partially to completely filled by landslide debris, volcaniclastic materials and sediments, or by relatively flat aprons of volcanic flows. Flexure creates a characteristic ‘dipole’ state of stress that influences subsequent magma ascent paths and chamber dynamics in the lithosphere. Compression in the upper lithosphere can inhibit magma ascent and favour the development of oblate magma chambers or sill complexes. This compression can be transferred into the edifice unless a décollement allows the volcano base to slip over the underlying lithosphere; generally, basal décollements are found to operate via high pore-fluid pressure in a clay sediment-based layer. Volcanoes lacking such a layer, regardless of the thickness of the basal sediments, lack basal décollements and, thus, tend to be limited in size by compressive stresses adverse to magma ascent.
How do you compute the midpoint of an interval?
Authors: Goualard Frédéric
Published: March 2014

The algorithm that computes the midpoint of an interval with floating-point bounds requires some careful devising to handle all possible inputs correctly. We review several implementations from prominent C/C++ interval arithmetic packages and analyze their potential failure to deliver the expected results. We then show how to amend them to avoid common pitfalls. The results presented are also relevant to noninterval arithmetic computation such as the implementation of bisection methods. Enough background on IEEE 754 floating-point arithmetic is provided for this article to serve as a practical introduction to the analysis of floating-point computation.
Online learning of timeout policies for dynamic power management
Authors: Khan Umair Ali , Rinner Bernhard
Published: March 2014

Dynamic power management (DPM) refers to strategies which selectively change the operational states of a device during runtime to reduce the power consumption based on the past usage pattern, the current workload, and the given performance constraint. The power management problem becomes more challenging when the workload exhibits nonstationary behavior which may degrade the performance of any single or static DPM policy.

This article presents a reinforcement learning (RL)-based DPM technique for optimal selection of timeout values in the different device states. Each timeout period determines how long the device will remain in a particular state before the transition decision is taken. The timeout selection is based on workload estimates derived from a Multilayer Artificial Neural Network (ML-ANN) and an objective function given by weighted performance and power parameters. Our DPM approach is further able to adapt the power-performance weights online to meet user-specified power and performance constraints, respectively. We have completely implemented our DPM algorithm on our embedded traffic surveillance platform and performed long-term experiments using real traffic data to demonstrate the effectiveness of the DPM. Our results show that the proposed learning algorithm not only adequately explores the power-performance trade-off with nonstationary workload but can also successfully perform online adjustment of the trade-off parameter in order to meet the user-specified constraint.
Embedded RAIDs-on-chip for bus-based chip-multiprocessors
Authors: Bathen Luis Angel D. , Dutt Nikil D.
Published: March 2014

The dual effects of larger die sizes and technology scaling, combined with aggressive voltage scaling for power reduction, increase the error rates for on-chip memories. Traditional on-chip memory reliability techniques (e.g., ECC) incur significant power and performance overheads. In this article, we propose a low-power-and-performance-overhead Embedded RAID (E-RAID) strategy and present Embedded RAIDs-on-Chip (E-RoC), a distributed dynamically managed reliable memory subsystem for bus-based Chip-Multiprocessors. E-RoC achieves reliability through redundancy by optimizing RAID-like policies tuned for on-chip distributed memories. We achieve on-chip reliability of memories through the use of Distributed Dynamic ScratchPad Allocatable Memories (DSPAMs) and their allocation policies. We exploit aggressive voltage scaling to reduce power consumption overheads due to parallel DSPAM accesses, and rely on the E-RoC Manager to automatically handle any resulting voltage-scaling-induced errors. We demonstrate how E-RAIDs can further enhance the fault tolerance of traditional memory reliability approaches by designing E-RAID levels that exploit ECC. Finally, we show the power and flexibility of the E-RoC concept by showing the benefits of having a heterogeneous E-RAID levels that fit each application's needs (fault tolerance, power/energy, performance).

Our experimental results on CHStone/Mediabench II benchmarks show that our E-RAID levels converge to 100% error-free data rates much faster than traditional ECC approaches. Moreover, E-RAID levels that exploit ECC can guarantee 99.9% error-free data rates at ultra low Vdd on average, where as traditional ECC approaches were able to attain at most 99.1% error-free data rates. We observe an average of 22% dynamic power consumption increase by using traditional ECC approaches with respect to the baseline (non-voltage scaled SPMs), whereas our E-RAID levels are able to save dynamic power consumption by an average of 27% (w.r.t. the same non-voltage scaled SPMs baseline), while incurring worst-case 2% higher performance overheads than traditional ECC approaches. By voltage scaling the memories, we see that traditional ECC approaches are able to save static energy by 6.4% (average), where as our E-RAID approaches achieve 23.4% static energy savings (average). Finally, we observe that mixing E-RAID levels allows us to further reduce the dynamic power consumption by up to 55.5% at the cost of an average 5.6% increase in execution time over traditional approaches.
Automatic feature generation for machine learning--based optimising compilation
Authors: Leather Hugh , Bonilla Edwin , O'boyle Michael
Published: March 2014

Recent work has shown that machine learning can automate and in some cases outperform handcrafted compiler optimisations. Central to such an approach is that machine learning techniques typically rely upon summaries or features of the program. The quality of these features is critical to the accuracy of the resulting machine learned algorithm; no machine learning method will work well with poorly chosen features. However, due to the size and complexity of programs, theoretically there are an infinite number of potential features to choose from. The compiler writer now has to expend effort in choosing the best features from this space. This article develops a novel mechanism to automatically find those features that most improve the quality of the machine learned heuristic. The feature space is described by a grammar and is then searched with genetic programming and predictive modelling. We apply this technique to loop unrolling in GCC 4.3.1 and evaluate our approach on a Pentium 6. On a benchmark suite of 57 programs, GCCs hard-coded heuristic achieves only 3% of the maximum performance available, whereas a state-of-the-art machine learning approach with hand-coded features obtains 59%. Our feature generation technique is able to achieve 76% of the maximum available speedup, outperforming existing approaches.
Socially desirable approximations for dodgson’s voting rule
Authors: Caragiannis Ioannis , Kaklamanis Christos , Karanikolas Nikos , Procaccia Ariel D.
Published: March 2014

In 1876, Charles Lutwidge Dodgson suggested the intriguing voting rule that today bears his name. Although Dodgson’s rule is one of the most well-studied voting rules, it suffers from serious deficiencies, both from the computational point of view—it is NP-hard even to approximate the Dodgson score within sublogarithmic factors—and from the social choice point of view—it fails basic social choice desiderata such as monotonicity and homogeneity. However, this does not preclude the existence of approximation algorithms for Dodgson that are monotonic or homogeneous, and indeed it is natural to ask whether such algorithms exist.

In this article, we give definitive answers to these questions. We design a monotonic exponential-time algorithm that yields a 2-approximation to the Dodgson score, while matching this result with a tight lower bound. We also present a monotonic polynomial-time O(log
m
)-approximation algorithm (where
m
is the number of alternatives); this result is tight as well due to a complexity-theoretic lower bound. Furthermore, we show that a slight variation on a known voting rule yields a monotonic, homogeneous, polynomial-time O(
m
log
m
)-approximation algorithm and establish that it is impossible to achieve a better approximation ratio even if one just asks for homogeneity. We complete the picture by studying several additional social choice properties; for these properties, we prove that algorithms with an approximation ratio that depends only on
m
do not exist.
Providing reliable and real-time delivery in the presence of body shadowing in breadcrumb systems
Authors: Liu Hengchang , Hui Pan , Xie Zhiheng , Li Jingyuan , Siu David , Zhou Gang , Huang Liusheng , Stankovic John A.
Published: March 2014

The primary goal of breadcrumb trail sensor networks is to transmit in real-time users' physiological parameters that measure life-critical functions to an incident commander through reliable multihop communication. In applications using breadcrumb solutions, there are often many users working together, and this creates a well-known body shadowing effect (BSE). In this article, we first measure the characteristics of body shadowing for 2.4GHz sensor nodes. Our empirical results show that the body shadowing effect leads to severe packet loss and consequently very poor real-time performance. Then we develop a novel
Intentional Forwarding
solution. This solution accurately detects the shadowing mode and enables selected neighbors to forward data packets. Experimental results from a fully implemented testbed demonstrate that Intentional Forwarding is able to improve the end-to-end average packet delivery ratio (PDR) from 58% to 93% and worst-case PDR from 45% to 85%, and is able to meet soft real-time requirements even under severe body shadowing problems.
Adaptive wear-leveling algorithm for PRAM main memory with a DRAM buffer
Authors: Park Sung Kyu , Maeng Min Kyu , Park Ki-Woong , Park Kyu Ho
Published: March 2014

Phase Change RAM (PRAM) is a candidate to replace DRAM main memory due to its low idle power consumption and high scalability. However, its latency and endurance have generated problems in fulfilling its main memory role. The latency can be treated with a DRAM buffer, but the endurance problem remains, with three critical points that need to be improved despite the use of, existing wear-leveling algorithms. First, existing DRAM buffering schemes do not consider write count distribution. Second, swapping and shifting operations are performed statically. Finally, swapping and shifting operations are loosely coupled with a DRAM buffer. As a remedy to these drawbacks, we propose an adaptive wear-leveling algorithm that consists of three novel schemes for PRAM main memory with a DRAM buffer. The PRAM-aware DRAM buffering scheme reduces the write count and prevents skewed writing by considering the write count and clean data based on the least recently used (LRU) scheme. The adaptive multiple swapping and shifting scheme makes the write count even with the dynamic operation timing, the number of swapping pages being based on the workload pattern. Our DRAM buffer-aware swapping and shifting scheme reduces overhead by curbing additional swapping and shifting operations, thus reducing unnecessary write operations. To evaluate the wear-leveling effect, we have implemented a PIN-based wear-leveling simulator. The evaluation confirms that the PRAM lifetime increases from 0.68 years with the previous wear-leveling algorithm to 5.32 years with the adaptive wear-leveling algorithm.
Message blinding method requiring no multiplicative inversion for RSA
Authors: Kim Heeseok , Han Dong-Guk , Hong Seokhie , Ha Jaecheol
Published: March 2014

This article proposes a new message blinding methods requiring no multiplicative inversion for RSA. Most existing message blinding methods for RSA additionally require the multiplicative inversion, even though computational complexity of this operation is
O
(
n
3
) which is equal to that of the exponentiation. Thus, this additional operation is known to be the main drawback of the existing message blinding methods for RSA. In addition to requiring no additional multiplicative inversion, our new countermeasure provides the security against various power analysis attacks as well as general differential power analysis.
A low-power instruction replay mechanism for design of resilient microprocessors
Authors: Rodrigues Rance , Annamalai Arunachalam , Kundu Sandip
Published: March 2014

There is a growing concern about the increasing rate of defects in computing substrates. Traditional redundancy solutions prove to be too expensive for commodity microprocessor systems. Modern microprocessors feature multiple execution units to take advantage of instruction level parallelism. However, most workloads do not exhibit the level of instruction level parallelism that a typical microprocessor is resourced for. This offers an opportunity to reexecute instructions using idle execution units. But, relying solely on idle resources will not provide full instruction coverage and there is a need to explore other alternatives. To that end, we propose and evaluate two instruction replay schemes within the
same core
for online testing of the execution units. One scheme (RER) reexecutes only the retired instructions, while the other (REI) reexecutes all the issued instructions. The complete proposed solution requires a comparator and minor modifications to control logic, resulting in negligible hardware overhead. Both soft and hard error detection are considered and the performance and energy impact of both schemes are evaluated and compared against previously proposed redundant execution schemes. Results show that even though the proposed schemes result in a small performance penalty when compared to previous work, the energy overhead is significantly reduced.
Transport triggered architecture to perform carrier synchronization for LTE
Authors: Anjum Omer , Ali Mubashir , Pitkänen Teemu , Nurmi Jari
Published: March 2014

In this article implementation of carrier frequency offset estimate for 20MHz LTE baseband processing is discussed. LTE (Long Term Evolution) is a wireless communication standard that makes use of some innovative techniques to gain very high data rates (>100Mbps). This goal for such a high throughput also imposes design challenges for the industry and academia such as in the case of handheld mobile devices where the power budget is very limited. Implicitly high throughput means we need more computation power and more energy. On the other hand industry is also struggling for a flexible hardware solution, or software defined a radio (SDR), to amortize the huge cost of required hardware changes as the wireless standards have kept evolving. Design innovations are now needed to confront those challenges of low power and flexible design without changing the hardware. The implementation is made on Transport Triggered Architecture (TTA), which is a unique concept in computer architecture design, based on the single instruction, “MOVE”. The power consumption of the architecture when synthesized on 180nm technology at 180MHz and 1.8V is 18.39mW. The total area occupied excluding memory is 0.6mm
2
. The proposed TTA solution has been compared with, a more ASIC (application specific integrated circuits), like ASIP (application specific instruction processor) solution and a coprocessor accelerator-based solution. The proposed solution is more flexible: easily programmable due to high level language support, easily scalable, and still efficient in energy consumption needed to complete the CFO (carrier frequency offset) estimation task. Because of these attractive characteristics, TTA is also a potential candidate for SDR platforms.
Bandwidth allocation for fixed-priority-scheduled compositional real-time systems
Authors: Dewan Farhana , Fisher Nathan
Published: March 2014

Recent research in compositional real-time systems has focused on determination of a component's real-time interface parameters. An important objective in interface-parameter determination is minimizing the bandwidth allocated to each component of the system while simultaneously guaranteeing component schedulability. With this goal in mind, in this article, we explore fixed-priority schedulability in compositional setting. First we derive an efficient exact test based on iterative convergence for sporadic task systems scheduled by fixed-priority (e.g., deadline monotonic, rate monotonic) upon an explicit-deadline periodic (EDP) resource. Then we address the time complexity of the exact test by developing a fully-polynomial-time approximation scheme (FPTAS) for allocating bandwidth to components. Our parametric algorithm takes the task system and an accuracy parameter ε > 0 as input and returns a bandwidth which is guaranteed to be at most a factor (1 + ε) times the optimal minimum bandwidth required to successfully schedule the task system. We perform thorough simulation over synthetically generated task systems to compare the performance of our proposed efficient-exact and the approximate algorithm and observe a significant decrease in runtime and a very small relative error when comparing the approximate algorithm with the exact algorithm and the sufficient algorithm.
Extended Instruction Exploration for Multiple-Issue Architectures
Authors: Wu I-Wei , Shann Jean Jyh-Jiun , Hsu Wei-Chung , Chung Chung-Ping
Published: March 2014

In order to satisfy the growing demand for high-performance computing in modern embedded devices, several architectural and microarchitectural enhancements have been implemented in processor architectures. Extended instruction (EI) is often used for architectural enhancement, while issuing multiple instructions is a common approach for microarchitectural enhancement. The impact of combining both of these approaches in the same design is not well understood. While previous studies have shown that EI can potentially improve performance in some applications on certain multiple-issue architectures, the algorithms used to identify EI for multiple-issue architectures yield only limited performance improvement. This is because not all arithmetic operations are suited for EI for multiple-issue architectures. To explore the full potential of EI for multiple-issue architectures, two important factors need to be considered: (1) the execution performance of an application is dominated by critical (located on the critical path) and highly resource-contentious (i.e., having a high probability of being delayed during execution due to hardware resource limitations) operations, and (2) an operation may become critical and/or highly resource contentious after some operations are added to the EI. This article presents an EI exploration algorithm for multiple-issue architectures that focuses on these two factors. Simulation results show that the proposed algorithm outperforms previously published algorithms.
A study on parallelizing XML path filtering using accelerators
Authors: Moussalli Roger , Salloum Mariam , Halstead Robert , Najjar Walid , Tsotras Vassilis J.
Published: March 2014

Publish-subscribe systems present the state of the art in information dissemination to multiple users. Such systems have evolved from simple topic-based to the current XML-based systems. XML-based pub-sub systems provide users with more flexibility by allowing the formulation of complex queries on the content as well as the structure of the streaming messages. Messages that match a given user query are forwarded to the user. This article examines how to exploit the parallelism found in XPath filtering. Using an incoming XML stream, parsing and matching thousands of user profiles are performed simultaneously by matching engines. We show the benefits and trade-offs of mapping the proposed filtering approach onto FPGAs, processing streams of XML at wire speed, and GPUs, providing the flexibility of software. This is in contrast to conventional approaches bound by the sequential aspect of software computing, associated with a large memory footprint. By converting XPath expressions into custom stacks, our solution is the first to provide support for complex XPath structural constructs, such as parent-child and ancestor descendant relations, whilst allowing wildcarding and recursion. The measured speedups resulting from the GPU and FPGA accelerations versus single-core CPUs are up to 6.6X and 2.5 orders of magnitude, respectively. The FPGA approaches are up to 31X faster than software running on 12 CPU cores.
A restricted multinomial hybrid selection procedure
Authors: Vieira Hélcio , Sanchez Susan M. , Sanchez Paul J. , Kienitz Karl Heinz , Belderrain Mischel Carmen Neyra
Published: March 2014

Analysts using simulation models often must assess a large number of alternatives in order to determine which are most effective. If effectiveness corresponds to the likelihood of yielding the best outcome, this becomes a multinomial selection problem. Unfortunately, existing procedures were developed primarily for evaluating small sets of alternatives, so parameters required to implement them may not be readily available or the sampling costs may be prohibitive when a large number of alternatives are present. We propose a truncated, sequential multinomial subset selection procedure that restricts the maximum subset size. Numerical comparisons show that our procedure can be much more efficient than the leading unrestricted procedure. Our procedure requires only one calculated parameter rather than four. We provide extensive tables for cases involving large numbers of alternatives.
Stochastic kriging with biased sample estimates
Authors: Chen Xi , Kim Kyoung-Kuk
Published: March 2014

Stochastic kriging has been studied as an effective metamodeling technique for approximating response surfaces in the context of stochastic simulation. In a simulation experiment, an analyst typically needs to estimate relevant metamodel parameters and further do prediction; therefore, the impact of parameter estimation on the performance of the metamodel-based predictor has drawn some attention in the literature. However, how the standard stochastic kriging predictor is affected by the presence of bias in finite-sample estimates has not yet been fully investigated. In this article, we study the predictive performance and investigate optimal budget allocation rules subject to a fixed computational budget constraint. Furthermore, we extend the analysis to two-level or nested simulation, which has been recently documented in the risk management literature, with biased estimators.
HMTT
Authors: Huang Yongbing , Chen Licheng , Cui Zehan , Ruan Yuan , Bao Yungang , Chen Mingyu , Sun Ninghui
Published: March 2014

DRAM access traces (i.e., off-chip memory references) can be extremely valuable for the design of memory subsystems and performance tuning of software. Hardware snooping on the off-chip memory interface is an effective and nonintrusive approach to monitoring and collecting real-life DRAM accesses. However, compared with software-based approaches, hardware snooping approaches typically lack semantic information, such as process/function/object identifiers, virtual addresses, and lock contexts, that is essential to the complete understanding of the systems and software under investigation.

In this article, we propose a hybrid hardware/software mechanism that is able to collect off-chip memory reference traces with semantic information. We have designed and implemented a prototype system called HMTT (Hybrid Memory Trace Tool), which uses a custom-made DIMM connector to collect off-chip memory references and a high-level event-encoding scheme to correlate semantic information with memory references. In addition to providing complete, undistorted DRAM access traces, the proposed system is also able to perform various types of low-overhead profiling, such as object-relative accesses and multithread lock accesses.
Endurance-aware cache line management for non-volatile caches
Authors: Wang Jue , Dong Xiangyu , Xie Yuan , Jouppi Norman P.
Published: March 2014

Nonvolatile memories (NVMs) have the potential to replace low-level SRAM or eDRAM on-chip caches because NVMs save standby power and provide large cache capacity. However, limited write endurance is a common problem for NVM technologies, and today's cache management might result in unbalanced cache write traffic, causing heavily written cache blocks to fail much earlier than others. Although wear-leveling techniques for NVM-based main memories exist, we cannot simply apply them to NVM-based caches. This is because cache writes have intraset variations as well as interset variations, while writes to main memories only have interset variations.

To solve this problem, we propose i
2
WAP, a new cache management policy that can reduce both inter- and intraset write variations. i
2
WAP has two features: Swap-Shift, an enhancement based on existing main memory wear leveling to reduce cache interset write variations, and Probabilistic Set Line Flush, a novel technique to reduce cache intraset write variations. Implementing i
2
WAP only needs two global counters and two global registers. In one of our studies, i
2
WAP can improve the NVM cache lifetime by 75% on average and up to 224%. We also validate that i
2
WAP is effective in systems with different cache configurations and workloads.
Comprehensible classification models
Authors: Freitas Alex A.
Published: March 2014

The vast majority of the literature evaluates the performance of classification models using only the criterion of predictive accuracy. This paper reviews the case for considering also the comprehensibility (interpretability) of classification models, and discusses the interpretability of five types of classification models, namely decision trees, classification rules, decision tables, nearest neighbors and Bayesian network classifiers. We discuss both interpretability issues which are specific to each of those model types and more generic interpretability issues, namely the drawbacks of using model size as the only criterion to evaluate the comprehensibility of a model, and the use of monotonicity constraints to improve the comprehensibility and acceptance of classification models by users.
Ensembles for unsupervised outlier detection
Authors: Zimek Arthur , Campello Ricardo J.G.B. , Sander Jörg
Published: March 2014

Ensembles for unsupervised outlier detection is an emerging topic that has been neglected for a surprisingly long time (although there are reasons why this is more difficult than supervised ensembles or even clustering ensembles). Aggarwal recently discussed algorithmic patterns of outlier detection ensembles, identified traces of the idea in the literature, and remarked on potential as well as unlikely avenues for future transfer of concepts from supervised ensembles. Complementary to his points, here we focus on the core ingredients for building an outlier ensemble, discuss the first steps taken in the literature, and identify challenges for future research.
Precarious Employment: Understanding an Emerging Social Determinant of Health
Authors: Benach J. , Vives A. , Amable M. , Vanroelen C. , Tarafa G. , Muntaner C.
Published: March 2014

Employment precariousness is a social determinant that affects the health of workers, families, and communities. Its recent popularity has been spearheaded by three main developments: the surge in “flexible employment” and its associated erosion of workers' employment and working conditions since the mid-1970s; the growing interest in social determinants of health, including employment conditions; and the availability of new data and information systems. This article identifies the historical, economic, and political factors that link precarious employment to health and health equity; reviews concepts, models, instruments, and findings on precarious employment and health inequalities; summarizes the strengths and weaknesses of this literature; and highlights substantive and methodological challenges that need to be addressed. We identify two crucial future aims: to provide a compelling research program that expands our understanding of employment precariousness and to develop and evaluate policy programs that effectively put an end to its health-related impacts.