bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemical sympathetic denervation, suppression of myocardial transient outward potassium current, and ventricular fibrillation in the rat
Authors: Bai Juan , Ren Chongyu , Hao Wei , Wang Rui , Cao Ji-Min
Published: October 2008

Sympathetic denervation is frequently observed in heart disease. To investigate the linkage of sympathetic denervation and cardiac arrhythmia, we developed a rat model of chemical sympathectomy by subcutaneous injections of 6-hydroxydopamine (6-OHDA). Cardiac sympathetic innervation was visualized by means of a glyoxylic catecholaminergic histofluorescence method. Transient outward current (Ito) of ventricular myocytes was recorded with the whole-cell configuration of the patch clamp technique. We observed that sympathectomy (i) decreased cardiac sympathetic nerve density and norepinephrine level, (ii) reduced the protein expression of Kv4.2, Kv1.4, and Kv channel-interacting protein 2 (KChIP2), (iii) decreased current densities and delayed activation of Ito channels, (iv) reduced the phosphorylation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) and cAMP response element-binding protein (CREB), and (v) increased the severity of ventricular fibrillation induced by rapid pacing. Three weeks after 6-OHDA injections, which allowed time for sympathetic regeneration, we found cardiac sympathetic nerve density, norepinephrine levels, expression levels of Kv4.2 and KChIP2 proteins, and Ito densities were partially normalized and ventricular fibrillation severity was decreased. We conclude that chemical sympathectomy downregulates the expression of selective Kv channel subunits and decreases myocardial Ito channel activities, contributing to the elevated susceptibility to ventricular fibrillation.
Potassium fluxes, energy metabolism, and oxygenation in intact diabetic rat hearts under normal and stress conditions
Authors: Jilkina Olga , Kuzio Bozena , Kupriyanov Valery V.
Published: October 2008

We evaluated the function of Na+/K+ATPase and sarcolemmal KATPchannels in diabetic rat hearts. Six weeks after streptozotocin (STZ) injection, unidirectional K+fluxes were assayed by using87rubidium (87Rb+) MRS. The hearts were loaded with Rb+by perfusion with Krebs–Henseleit buffer, in which 50% of K+was substituted with Rb+. The rate constant of Rb+uptake via Na+/K+ATPase was reduced. KATP-mediated Rb+efflux was activated metabolically with 2,4-dinitrophenol (DNP, 50 µmol·L–1) or pharmacologically with a KATPchannel opener, P-1075 (5 µmol·L–1). Cardiac energetics were monitored by using31P MRS and optical spectroscopy. DNP produced a smaller ATP decrease, yet similar Rb+efflux activation in STZ hearts. In K+-arrested hearts, P-1075 had no effect on high-energy phosphates and stimulated Rb+efflux by interaction with SUR2A subunit of KATPchannel; this stimulation was greater in STZ hearts. In normokalemic hearts, P-1075 caused cardiac arrest and ATP decline, and the stimulation of Rb+efflux was lower in normokalemic STZ hearts arrested by P-1075. Thus, the Rb+efflux stimulation in STZ hearts was altered depending on the mode of KATPchannel activation: pharmacologic stimulation (P-1075) was enhanced, whereas metabolic stimulation (DNP) was reduced. Both the basal concentration of phosphocreatine ([PCr]) and [PCr]/[ATP] were reduced; nevertheless, the STZ hearts were more or equally resistant to metabolic stress.
Pulmonary feedback and gestational age-dependent regulation of fetal breathing movements
Authors: Hasan Shabih U. , Bharadwaj Baikunth , Remmers John E. , Patel Avni , Rigaux Anita , Schneider Jennifer
Published: October 2008

Prenatal lung development requires fetal breathing movements (FBM). To investigate the dependence of FBM on feedback originating from the lung, we hypothesized that pneumonectomy stimulates FBM. Time-dated fetal sheep underwent bilateral pneumonectomy, unilateral pneumonectomy, or sham surgery at 125–130 days gestation. The incidence of FBM decreased in sham-operated fetuses at 142 days versus 130 days (p = 0.013), but was unchanged across all gestational ages in bilaterally pneumonectomized fetuses (p ≥ 0.52). In unilaterally pneumonectomized fetuses, the incidence of FBM remained unchanged until 139 days and was higher than that of the bilaterally pneumonectomized fetuses at 130–136 days gestation (p ≤ 0.03). The amplitude of integrated diaphragmatic electromyographic activity (∫EMGdi) and total respiratory output (frequency of breathing × ∫EMGdi) were lower in pneumonectomized fetuses versus sham-operated fetuses at later gestational ages (p < 0.05). These decreases in ∫EMGdiand total respiratory output were most pronounced at 142 days in bilaterally pneumonectomized fetuses versus sham-operated fetuses (p = 0.006 and 0.016, respectively). Low-voltage electrocortical activity (ECoG) increased, and high-voltage ECoG decreased, in unilaterally pneumonectomized fetuses compared with sham-operated fetuses (p = 0.04). In conclusion, we provide new evidence that feedback from the fetal lung modulates the incidence and various components of phrenic nerve output, suggesting a positive feedback mechanism between FBM and lung development.
SHEAR VISCOSITY OF HOT QGP AT FINITE CHEMICAL POTENTIAL
Authors: LIU HUI , HOU DEFU , LI JIARONG
Published: October 2008

The shear viscosity of quark–gluon plasma (QGP) at leading logarithm order at finite temperature and chemical potential in weakly coupled limit is studied by solving transport equations. The result shows that the chemical potential effect adds a positive μ2/T2 correction to the pure temperature case and thus increases the shear viscosity.
DIMENSIONAL REDUCTION AND THE TCP THEOREM IN THE SUPERSTRING THEORY
Authors: POLLOCK M. D.
Published: October 2008

Previously, we have shown that the Kasner solution [Formula: see text] to the D = (M+N+1)-dimensional vacuum Einstein theory [Formula: see text], where dx2 and dy2 are flat spaces of dimensionality M and N, respectively, exists only for (M - N)2 = M + N, that is D = 2+4K(K + 1), 1 + 4L2. The first three quantum numbers K = 0, 1, 2 for even D correspond to the three superstring dimensionalities D = 2, 10, 26 and are also given by the condition D = 2 mod 8 for the existence of Majorana–Weyl fermions. Here, we explain this result in terms of world-sheet symmetry and the TCP theorem applied to the superstring theory, the no-scale metric exhibiting T non-invariance which compensates the CP non-invariance due to the fermions, whose chirality thus gives the cosmological arrow of time its sense of direction.
BREMSSTRAHLUNG EMISSION DURING α-DECAY OF 226Ra
Authors: GIARDINA GIORGIO , FAZIO GIOVANNI , MANDAGLIO GIUSEPPE , MANGANARO MARINA , MAYDANYUK SERGHEI P. , OLKHOVSKY VLADISLAV S. , EREMIN NIKOLAY V. , PASKHALOV ANTON A. , SMIRNOV DMITRY A. , SACCÁ CARMELO
Published: October 2008

We obtained the spectrum of probability of the bremsstrahlung emission accompanying the α-decay of 226 Ra (Eα = 4.8 MeV ) by measuring the α-γ coincidences and using the model presented in our previous study on the α-decay of 214 Po (Eα = 7.7 MeV ). We compare the experimental data with the quantum mechanical calculation and find a good agreement between theory and experiment. We discuss the differences between the photon spectra connected with the α-decay of the 226 Ra and 214 Po nuclei. For the two mentioned nuclei, we analyze the bremsstrahlung emission contributions from the tunneling and external regions of the nucleus barrier into the total spectrum, and we find the destructive interference between these contributions. We also find that the emission of photons during tunneling of the α-particle gives an important contribution to the bremsstrahlung spectrum in the whole Eγ energy range of the studied 226 Ra nucleus.
PHASES OF HIGHER DIMENSIONAL BLACK HOLES
Authors: NIARCHOS VASILIS
Published: October 2008

We review some of the most striking properties of the phase diagrams of higher dimensional black holes in pure gravity. We focus on static black hole solutions with Kaluza–Klein asymptotics and stationary black hole solutions in flat Minkowski space. Both cases exhibit a rich pattern of interconnected phases and merger points with topology changing transitions. In the first case, the phase diagram includes uniform and non-uniform black strings, localized black holes and sequences of Kaluza–Klein bubbles. In the latter case, it includes Myers–Perry black holes, black rings, black saturns and pinched black holes.
Fault reactivation in the Port Campbell Embayment with respect to carbon dioxide sequestration, Otway Basin, Australia
Authors: Rogers Claire , van Ruth Peter J. , Hillis Richard R.
Published: October 2008

The Naylor structure in the Port Campbell Embayment, Otway Basin, South Australia is proposed as a demonstration site for the subsurface geological storage of carbon dioxide (CO
2
). The Naylor structure is a fault‐bounded high with normal faults to the north and west to SW. Seismic interpretation shows evidence of recent fault reactivation in the Otway Basin. It is postulated that residual hydrocarbon columns (accumulated and leaked prior to present day) in the Otway Basin leaked due to fault reactivation. Thus, a critical issue in the geological storage of CO
2
in the Port Campbell Embayment is the potential for the reactivation of faults bounding the Naylor structure.

The propensity of faults to be reactivated is assessed by determining the
in‐situ
stress field, the mechanical properties of the fault rock and the orientations of the existing faults. The
in‐situ
stress field lies on the boundary of a strike‐slip and reverse faulting regime in the Port Campbell Embayment. The vertical, minimum horizontal and maximum horizontal stress gradients are 21 MPa km
−1
, 19 MPa km
−1
and 38 MPa km
−1
respectively and the pore pressure gradient is hydrostatic. The maximum horizontal stress in the Port Campbell Embayment is oriented at 150°N.

One planar and two curviplanar faults were identified within the Naylor structure. Two fault segments act to trap accumulations at the crest of the structure. These fault segments have relatively low propensities to reactivate near the crest of the structure. The intended migration pathway of the CO
2
plume does not intersect the identified faults until it reaches the crest of the Naylor structure. However, reservoir heterogeneities such as sub‐seismic faults may cause the migrating CO
2
plume to move towards identified fault segments which are not intended to trap the injected CO
2
and have a relatively high propensity to reactivate.
The effects of Cenozoic compression within the Faroe-Shetland Basin and adjacent areas
Authors: Ritchie J. Derek , Johnson Howard , Quinn Martyn F. , Gatliff Robert W.
Published: October 2008

The effects of Cenozoic compression within the Faroe–Shetland Basin and surrounding areas are mainly manifested in the form of growth folds. The scale and orientation of the folds varies significantly, with axial trace lengths ranging between less than 10 to over 250 km and trends including east, NE-, NNE-, ENW-, NNW- and WNW. The NE-trending features are the most numerous, though they are mainly restricted to the NE Faroe–Shetland Basin where an inherited Caledonian structural grain is most prevalent. Limited evidence exists for late Paleocene and early Eocene activity along the Wyville Thomson Ridge, whereas mid–late Eocene and Oligocene fold growth is more common in the SW Faroe–Shetland Basin. Although the effects of well-defined early–mid Miocene deformation appear to be mainly constrained to the NE Faroe–Shetland Basin, this phase of activity is also inferred to have been responsible for major growth of the Wyville Thomson Ridge. Early Pliocene fold growth is observed within the Faroe–Shetland Basin and adjacent areas, with raised seabed profiles over some of the anticlinal features suggesting that the effects of compressional stress continue at the present day. Despite the variation in trend and size of growth folds, there is, we believe, similarity in their local mechanism of emplacement, with buttressing of sedimentary successions against pre-existing basement architecture and igneous intrusions being of particular significance. However, the lack of obvious spatial or temporal pattern to fold growth development within the NE Atlantic margin as a whole mitigates against a single regional driving mechanism being able to explain the current distribution, orientation and timing of the folds.
Compressional structures on the West Iberia rifted margin: controls on their distribution
Authors: Péron-Pinvidic G. , Manatschal G. , Dean S. M. , Minshull T. A.
Published: October 2008

The West Iberia margin is a magma-poor rifted margin that resulted from Jurassic to Cretaceous polyphase rifting leading to the opening of the North Atlantic Ocean. The Mesozoic rift structures were overprinted by two compressive tectonic events during Eocene and Miocene times resulting from collision between Iberia, Europe and Africa. The effects of these compressive tectonic events are expressed by faults and folds within the post-rift sedimentary sequence. We mapped and studied these Cenozoic deformation structures throughout the Southern Iberia Abyssal Plain (40°–41°N, 11°–13°W) on the basis of an extensive dataset of time migrated seismic profiles acquired by various academic institutions. Acoustic basement has also been analysed on the basis of its seismic aspect, in order to test potential relationships with the distribution of the post-rift sedimentary deformation.

Our observations lead to three major conclusions concerning the deformation affecting the post-rift sediments in the Southern Iberia Abyssal Plain: (1) the deformation occurs within the zone of exhumed continental mantle and not at its transition to continental or oceanic crust; (2) it is localized within a zone overlying basement with well-defined seismic characteristics; and (3) it is closely related to the major topographic features observed in the ocean–continent transition. The localization of the deformation within the zone of exhumed continental mantle and not at its boundaries to the adjacent oceanic and continental crust suggests that the limits between the different types of crust are transitional rather than sharp. Our results show that the zone of exhumed continental mantle represents the weakest zone within the margin that is preferentially deformed during initial convergence. At higher convergence rates, this zone may coincide with the location of a future subduction.
Elastic flexure and distributed deformation along Australia's North West Shelf: Neogene tectonics of the Bonaparte and Browse basins
Authors: Keep Myra , Harrowfield Mathew
Published: October 2008

Neogene collision between Australia and the Banda Arc modified the adjacent Bonaparte and Browse basins of the North West Shelf of Australia. Modification comprised both continuous long-wavelength amplification of Permo-Carboniferous basement topography and flexure and normal faulting of Triassic–Recent sedimentary cover. Deformation was continuous across the Browse and Bonaparte basins, despite the basins beings separated by a rupture-barrier style accommodation zone, the Browse–Bonaparte Transition. The degree of basement control and mechanisms of fault linkage vary significantly across this transition, and reflect differences in the structural relief, amplitude and depth of rifted basement either side of the transition. Neogene collision amplified the architectural divide. Amplification of basement topography over wavelengths of several hundred kilometres was associated with negligible horizontal length change. The transcurrent component of Neogene deformation was partitioned outboard of any continuous flexural amplification.
Security and identification indicators for browsers against spoofing and phishing attacks
Authors: Herzberg Amir , Jbara Ahmad
Published: October 2008

In spite of the use of standard Web security measures (SSL/TLS), users enter sensitive information such as passwords into fake Web sites. Such fake sites cause substantial damages to individuals and corporations. In this work, we identify several vulnerabilities of browsers, focusing on security and identification indicators.

We present improved security and identification indicators, as we implemented in TrustBar, a browser extension we developed. With TrustBar, users can assign a name or logo to identify SSL/TLS-protected sites; if users did not assign a name or logo, TrustBar identifies protected sites by the name or logo of the site, and by the certificate authority (CA) who identified the site.

We present usability experiments which compared TrustBar's indicators to the basic indicators available in most browsers (padlock, URL, and https prefix), and some relevant secure-usability principles.
Security analysis of Internet technology components enabling globally distributed workplaces—a framework
Authors: Gupta Manish , Banerjee Shamik , Agrawal Manish , Rao H. Raghav
Published: October 2008

As organizations increasingly operate, compete, and cooperate in a global context, business processes are also becoming global to propagate the benefits from coordination and standardization across geographical boundaries. In this context, security has gained significance due to increased threats, as well as legislation and compliance issues. This article presents a framework for assessing the security of Internet technology components that support a globally distributed workplace. Four distinct information flow and design architectures are identified based on location sensitivities and placements of the infrastructure components. Using a combination of scenarios, architectures, and technologies, the article presents the framework of a development tool for information security officers to evaluate the security posture of an information system. To aid managers in better understanding their options to improve security of the system, we also propose a three-dimensional representation, based on the framework, for embedding solution alternatives. To demonstrate its use in a real-world context, the article also applies the framework to assess a globally distributed workforce application at a northeast financial institution.
Semantics-based composition-oriented discovery of Web services
Authors: Brogi Antonio , Corfini Sara , Popescu Razvan
Published: October 2008

Service discovery and service aggregation are two crucial issues in the emerging area of service-oriented computing (SOC). We propose a new technique for the discovery of (Web) services that accounts for the need of composing several services to satisfy a client query. The proposed algorithm makes use of OWL-S ontologies, and explicitly returns the sequence of atomic process invocations that the client must perform in order to achieve the desired result. When no full match is possible, the algorithm features a flexible matching by returning partial matches and by suggesting additional inputs that would produce a full match.
Resource space model, OWL and database
Authors: Zhuge Hai , Xing Yunpeng , Shi Peng
Published: October 2008

Semantics exhibits diversity in the real world, mental abstraction world, document world, and machine world. Studying mappings between different forms of semantics helps unveil the uniformity in the diversity. This article investigates the mappings between three typical semantic models: the Web ontology language (OWL), relational database model, and resource space model (a classification-based semantic model). By establishing mappings between the semantic primitives of the three models, we study the mapping from OWL description onto resource space and analyze the normal forms of the generated resource space. Mapping back from resource space onto OWL description is then discussed. Further, we investigate the mapping between OWL description and relational database, as well as the mapping between relational database and resource space. Normal forms of the generated relational tables are analyzed. To support advanced applications on the future Web, we suggest integrating the resource space, OWL, and databases to form a powerful semantic platform that enables different semantic models to enhance each other.
Improving Web search using image snippets
Authors: Xue Xiao-Bing , Zhou Zhi-Hua , Zhang Zhongfei (Mark)
Published: October 2008

The Web has become the largest information repository in the world; thus, effectively and efficiently searching the Web becomes a key challenge. Interactive Web search divides the search process into several rounds, and for each round the search engine interacts with the user for more knowledge of the user's information requirement. Previous research mainly uses the text information on Web pages, while little attention is paid to other modalities. This article shows that Web search performance can be significantly improved if imagery is considered in interactive Web search. Compared with text, imagery has its own advantage: the time for “reading” an image is as little as that for reading one or two words, while the information brought by an image is as much as that conveyed by a whole passage of text. In order to exploit the advantages of imagery, a novel interactive Web search framework is proposed, where
image snippets
are first extracted from Web pages and then provided, along with the text snippets, to the user for result presentation and relevance feedback, as well as being presented alone to the user for image suggestion. User studies show that it is more convenient for the user to identify the Web pages he or she expects and to reformulate the initial query. Further experiments demonstrate the promise of introducing multimodal techniques into the proposed interactive Web search framework.
Schedulability analysis of preemptive and nonpreemptive EDF on partial runtime-reconfigurable FPGAs
Authors: Guan Nan , Deng Qingxu , Gu Zonghua , Xu Wenyao , Yu Ge
Published: October 2008

Field Programmable Gate Arrays (FPGAs) are very popular in today's embedded systems design, and Partial Runtime-Reconfigurable (PRTR) FPGAs allow HW tasks to be placed and removed dynamically at runtime. Hardware task scheduling on PRTR FPGAs brings many challenging issues to traditional real-time scheduling theory, which have not been adequately addressed by the research community compared to software task scheduling on CPUs. In this article, we consider the schedulability analysis problem of HW task scheduling on PRPR FPGAs. We derive utilization bounds for several variants of global preemptive/nonpreemptive EDF scheduling, and compare the performance of different utilization bound tests.
Efficiently scheduling runtime reconfigurations
Authors: Resano Javier , Clemente Juan Antonio , Gonzalez Carlos , Mozos Daniel , Catthoor Francky
Published: October 2008

Due to the emergence of portable devices that must run complex dynamic applications there is a need for flexible platforms for embedded systems. Runtime reconfigurable hardware can provide this flexibility but the reconfiguration latency can significantly decrease the performance. When dealing with task graphs, runtime support that schedules the reconfigurations in advance can drastically reduce this overhead. However, executing complex scheduling heuristics at runtime may generate an excessive penalty. Hence, we have developed a hybrid design-time/runtime reconfiguration scheduling heuristic that generates its final schedule at runtime but carries out most computations at design-time. We have tested our approach in a PowerPC 405 processor embedded on a FPGA demonstrating that it generates a very small runtime penalty while providing almost as good schedules as a full runtime approach.
Access pattern-based code compression for memory-constrained systems
Authors: Ozturk Ozcan , Kandemir Mahmut , Chen Guangyu
Published: October 2008

As compared to a large spectrum of performance optimizations, relatively less effort has been dedicated to optimize other aspects of embedded applications such as memory space requirements, power, real-time predictability, and reliability. In particular, many modern embedded systems operate under tight memory space constraints. One way of addressing this constraint is to compress executable code and data as much as possible. While researchers on code compression have studied efficient hardware and software based code compression strategies, many of these techniques do not take application behavior into account; that is, the same compression/decompression strategy is used irrespective of the application being optimized. This article presents an application-sensitive code compression strategy based on control flow graph (CFG) representation of the embedded program. The idea is to start with a memory image wherein all basic blocks of the application are compressed, and decompress only the blocks that are predicted to be needed in the near future. When the current access to a basic block is over, our approach also decides the point at which the block could be compressed. We propose and evaluate several compression and decompression strategies that try to reduce memory requirements without excessively increasing the original instruction cycle counts. Some of our strategies make use of profile data, whereas others are fully automatic. Our experimental evaluation using seven applications from the MediaBench suite and three large embedded applications reveals that the proposed code compression strategy is very successful in practice. Our results also indicate that working at a basic block granularity, as opposed to a procedure granularity, is important for maximizing memory space savings.
Auxiliary state machines + context-triggered properties in verification
Authors: Banerjee Ansuman , Dasgupta Pallab , Chakrabarti P. P.
Published: October 2008

Formal specifications of interface protocols between a design-under-test and its environment mostly consist of two types of correctness requirements, namely (a) a set of invariants that applies throughout the protocol execution and (b) a set of
context-triggered
properties that applies only when the protocol state belongs to a specific set of contexts. To model such requirements, an increasingly popular design choice in the assertion IP design community has been the use of abstract
context state machines
and state-oriented properties. In this paper, we formalize this modeling style and present algorithms for verifying such specifications. Specifically, we present a purely formal approach and a semi-formal approach for verifying such specifications. We demonstrate the use of this design style in modeling some of the industry standard protocol descriptions and present encouraging results.
Layout-aware scan chain reorder for launch-off-shift transition test coverage
Authors: Wang Sying-Jyan , Peng Kuo-Lin , Hsiao Kuang-Cyun , Li Katherine Shu-Min
Published: October 2008

Launch-off-shift (LOS) is a popular delay test technique for scan-based designs. However, it is usually not possible to achieve good delay fault coverage in LOS test due to conflicts in test vectors. In this article, we propose a layout-based scan chain ordering method to improve fault coverage for LOS test with limited routing overhead. A fast and effective algorithm is used to eliminate conflicts in test vectors while at the same time restrict the extra scan chain routing. This approach provides many advantages. (1) The proposed method can improve delay fault coverage for LOS test. (2) With layout information taken into account, the routing penalty is limited, and thus the impact on circuit performance will not be significant. Experimental results show that the proposed LOS test method achieves about the same level of delay fault coverage as enhanced scan does, while the average scan chain wire length is about 2.2 times of the shortest scan chain.
Timing-aware power-optimal ordering of signals
Authors: Moiseev Konstantin , Kolodny Avinoam , Wimer Shmuel
Published: October 2008

A computationally efficient technique for reducing interconnect active power in VLSI systems is presented. Power reduction is accomplished by simultaneous wire spacing and net ordering, such that cross-capacitances between wires are optimally shared. The existence of a unique power-optimal wire order within a bundle is proven, and a method to construct this order is derived. The optimal order of wires depends only on the activity factors of the underlying signals; hence, it can be performed prior to spacing optimization. By using this order of wires, optimality of the combined solution is guaranteed (as compared with any other ordering and spacing of the wires). Timing-aware power optimization is enabled by simultaneously considering timing criticality weights and activity factors for the signals. The proposed algorithm has been applied to various interconnect layouts, including wire bundles from high-end microprocessor circuits in 65 nm technology. Interconnect power reduction of 17% on average has been observed in such bundles.
Effective decap insertion in area-array SoC floorplan design
Authors: Lu Chao-Hung , Chen Hung-Ming , Liu Chien-Nan Jimmy
Published: October 2008

As VLSI technology enters the nanometer era, supply voltages continue to drop due to the reduction of power dissipation, but it makes power integrity problems even worse. Employing decoupling capacitances (decaps) in floorplan stage is a common approach to alleviating supply noise problems. Previous researches overestimate the decap budget and do not fully utilize the empty space of the floorplan. A floorplan usually has a lot of available space that can be used to insert the decap without increasing the floorplan area. Therefore, the goal of this work is to develop a better model to calculate the required decap to solve the power supply noise problem in area-array based designs, and increase the usage of available space in the floorplan to reduce the area overhead caused by decap insertion. The experimental results of this work are encouraging. Compared with previous approaches, our methodology reduces 38% of the decap budget in average for MCNC benchmarks but can still meet the power supply noise requirements. The final floorplan areas with decap are also smaller than the numbers reported in previous works.
Constraint-driven floorplan repair
Authors: Moffitt Michael D. , Roy Jarrod A. , Markov Igor L. , Pollack Martha E.
Published: October 2008

In this work, we propose a new and efficient approach to the
floorplan repair
problem, where violated design constraints are satisfied by applying small changes to an existing rough floorplan. Such a floorplan can be produced by a human designer, a scalable placement algorithm, or result from engineering adjustments to an existing floorplan. In such cases, overlapping modules must be separated, and others may need to be repositioned to satisfy additional requirements. Our algorithmic framework uses an expressive graph-based encoding of constraints which can reflect fixed-outline, region, proximity and alignment constraints. By tracking the implications of existing constraints, we resolve violations by imposing gradual modifications to the floorplan, in an attempt to preserve the characteristics of its initial design. Empirically, our approach is effective at removing overlaps and repairing violations that may occur when design constraints are acquired and imposed dynamically.
Power laws in software
Authors: Louridas Panagiotis , Spinellis Diomidis , Vlachos Vasileios
Published: October 2008

A single statistical framework, comprising power law distributions and scale-free networks, seems to fit a wide variety of phenomena. There is evidence that power laws appear in software at the class and function level. We show that distributions with long, fat tails in software are much more pervasive than previously established, appearing at various levels of abstraction, in diverse systems and languages. The implications of this phenomenon cover various aspects of software engineering research and practice.
How people recall, recognize, and reuse search results
Authors: Teevan Jaime
Published: October 2008

When a person issues a query, that person has expectations about the search results that will be returned. These expectations can be based on the current information need, but are also influenced by how the searcher believes the search engine works, where relevant results are expected to be ranked, and any previous searches the individual has run on the topic. This paper looks in depth at how the expectations people develop about search result lists during an initial query affect their perceptions of and interactions with future repeat search result lists. Three studies are presented that give insight into how people recall, recognize, and reuse results. The first study (a study of
recall
) explores what people recall about previously viewed search result lists. The second study (a study of
recognition
) builds on the first to reveal that people often recognize a result list as one they have seen before even when it is quite different. As long as those aspects that the searcher remembers about the initial list remain the same, other aspects can change significantly. This is advantageous because, as the third study (a study of
reuse
) shows, when a result list appears to have changed, people have trouble re-using the previously viewed content in the list. They are less likely to find what they are looking for, less happy with the result quality, more likely to find the task hard, and more likely to take a long time searching. Although apparent consistency is important for reuse, people's inability to recognize change makes consistency without stagnation possible. New relevant results can be presented where old results have been forgotten, making both old and new content easy to find.
Improved search engines and navigation preference in personal information management
Authors: Bergman Ofer , Beyth-Marom Ruth , Nachmias Rafi , Gradovitch Noa , Whittaker Steve
Published: October 2008

Traditionally users access their personal files mainly by using folder navigation. We evaluate whether recent improvements in desktop search have changed this fundamental aspect of Personal Information Management (PIM). We tested this in two studies using the same questionnaire: (a) The Windows Studya longitudinal comparison ofGoogle DesktopandWindows XP Search Companion, and (b) The Mac Studya large scale comparison of MacSpotlightandSherlock. There were few effects for improved search. First, regardless of search engine, there was a strong navigation preference: on average, users estimated that they used navigation for 56-68% of file retrieval events but searched for only 4-15% of events. Second, the effect of improving the quality of the search engine on search usage was limited and inconsistent. Third, search was used mainly as a last resort when users could not remember file location. Finally, there was no evidence that using improved desktop search engines leads people to change their filing habits to become less reliant on hierarchical file organization. We conclude by offering theoretical explanations for navigation preference, relating to differences between PIM and Internet retrieval, and suggest alternative design directions for PIM systems.
Meta methods for model sharing in personal information systems
Authors: Siersdorfer Stefan , Sizov Sergej
Published: October 2008

This article introduces a methodology for automatically organizing document collections into thematic categories for Personal Information Management (PIM) through collaborative sharing of machine learning models in an efficient and privacy-preserving way. Our objective is to combine multiple independently learned models from several users to construct an advanced ensemble-based decision model by taking the knowledge of multiple users into account in a decentralized manner, for example, in a peer-to-peer overlay network. High accuracy of the corresponding supervised (classification) and unsupervised (clustering) methods is achieved by restrictively leaving out uncertain documents rather than assigning them to inappropriate topics or clusters with low confidence. We introduce a formal probabilistic model for the resulting ensemble based meta methods and explain how it can be used for constructing estimators and for goal-oriented tuning. Comprehensive evaluation results on different reference data sets illustrate the viability of our approach.
Editorial
Authors: Marchionini Gary
Published: October 2008

Peer review is an important resource of scholarly communities and must be managed and nurtured carefully. Electronic manuscript management systems have begun to improve some aspects of workflow for conferences and journals but also raise issues related to reviewer roles and reputations and the control of reviews over time. Professional societies should make their policies related to reviews and reviewer histories clear to authors and reviewers, develop strategies and tools to facilitate good and timely reviews, and facilitate the training of new reviewers.
Context as Support for Learning Computer Organization
Authors: Tew Allison Elliott , Dorn Brian , Leahy William D. , Guzdial Mark
Published: October 2008

The ubiquity of personal computational devices in the lives of today's students presents a meaningful context for courses in computer organization beyond the general-purpose or imaginary processors routinely used. This article presents results of a comparative study examining student performance in a conventional organization course and in one that has been contextualized using a personal gaming platform as the pedagogical architecture. We find minimal differences in student learning but significant motivation and engagement gains for those in the contextualized course.
Hypertext 2008
Authors: Millard David E.
Published: October 2008

The 21
st
ACM Conference on Hypertext and Hypermedia was held in Pittsburgh, PA from June 19th to 21st of 2008. Like all great coming-of-age parties it was a mix of celebrating the past and looking forward with excitement to the future. Over the last few years the conference has grown in scope to cover a wide range of trends and technologies concerned with connecting information and people. This year the main themes were Information Linking and Organization, Social Linking, Applications of Hypertext, and Hypertext, Culture and Communications; once more attracting a fascinating mix of people from both the technical and literary worlds.
Interview with Frank Shipman
Authors: Atzenbeck Claus
Published: October 2008

Frank Shipman is a Professor in the Department of Computer Science and Associate Director of the TEES Center for the Study of Digital Libraries. He has been pursuing research in the areas of hypermedia, computer-supported cooperative work, multimedia, computers and education, and intelligent user interfaces since 1987. Dr. Shipman's work at Baylor College of Medicine, the University of Colorado, Xerox PARC, and Texas A&M University investigates the design and use of media combining informal and formal representations and methods for supporting incremental formalization. This work included helping in the design and development of a number of collaborative hypermedia systems including the Virtual Notebook System, the Hyper-Object Substrate, VIKI, the Visual Knowledge Builder, Walden's Paths, and Hyper-Hitchcock.
Automatic document-level semantic metadata annotation using folksonomies and domain ontologies
Authors: Al-Khalifa Hend S. , Rubart Jessica
Published: October 2008

Hend S. Al-Khalifa received her PhD from the School of Electronics and Computer Science, University of Southampton, United Kingdom. The title of her thesis is "Automatic Document-Level Semantic Metadata Annotation Using Folksonomies and Domain Ontologies". She currently works as an assistant professor in the Information Technology Department, College of Computer and Information Sciences, King Saud University, Saudi Arabia. Her research interests include web technologies (i.e. Semantic Web/Web 2.0), Technology Enhanced Learning (e.g. E-learning, Adaptive Hypermedia, etc.) and computer for people with special needs. (website: http://faculty.ksu.edu.sa/hend.alkhalifa)
A backtracking-based algorithm for hypertree decomposition
Authors: Gottlob Georg , Samer Marko
Published: October 2008

Hypertree decompositions of hypergraphs are a generalization of tree decompositions of graphs. The corresponding hypertree-width is a measure for the acyclicity and therefore an indicator for the tractability of the associated computation problem. Several NP-hard decision and computation problems are known to be tractable on instances whose structure is represented by hypergraphs of bounded hypertree-width. Roughly speaking, the smaller the hypertree-width, the faster the computation problem can be solved. In this paper, we present the new backtracking-based algorithm det-
k
-decomp for computing hypertree decompositions of small width. Our benchmark evaluations have shown that det-
k
-decomp significantly outperforms opt-
k
-decomp, the only exact hypertree decomposition algorithm so far. Even compared to the best heuristic algorithm, we obtained competitive results as long as the hypergraphs are sufficiently simple.
Computing an approximation of the 1-center problem on weighted terrain surfaces
Authors: Lanthier Mark A. , Nussbaum Doron , Wang Tsuo-Jung
Published: October 2008

In this article, we discuss the problem of determining a meeting point of a set of scattered robots
R
= {
r
1
,
r
2
,…,

r
s

} in a weighted terrain P, which has
n
>
s
triangular faces. Our algorithmic approach is to produce a discretization of P by producing a graph
G
= {

V
G

,

E
G

}, which lies on the surface of P. For a chosen vertex
p′
∈

V
G

, we define ‖Π(

r
i

,
p′
)‖ as the minimum weight cost of traveling from

r
i

to
p′
. We show that min

p′
∈

V
G

{max

1≤
i
≤
s

{‖Π(

r
i

,
p′
)‖}} ≤ min

p
*∈P

{max

1≤
i
≤
s

{‖Π(

r
i

,
p
*)‖}} + 2
W
|
L
|, where
L
is the longest edge of P,
W
is the maximum cost weight of a face of P, and
p
* is the optimal solution. Our algorithm requires
O
(
snm
log(
snm
) +
snm
2
) time to run, where
m
=
n
in the Euclidean metric and
m
=
n
2
in the weighted metric. However, we show, through experimentation, that only a constant value of
m
is required (e.g., m = 8) in order to produce very accurate solutions (< 1% error). Hence, for typical terrain data, the expected running time of our algorithm is
O
(
sn
log(
sn
)). Also, as part of our experiments, we show that by using geometrical subsets (i.e., 2D/3D convex hulls, 2D/3D bounding boxes, and random selection) of the robots we can improve the running time for finding
p′
, with minimal or no additional accuracy error when comparing
p′
to
p
*.
Data reduction and exact algorithms for clique cover
Authors: Gramm Jens , Guo Jiong , Hüffner Falk , Niedermeier Rolf
Published: October 2008

To cover the edges of a graph with a minimum number of cliques is an NP-hard problem with many applications. For this problem we develop efficient and effective polynomial-time data reduction rules that, combined with a search tree algorithm, allow for exact problem solutions in competitive time. This is confirmed by experiments with real-world and synthetic data. Moreover, we prove the fixed-parameter tractability of covering edges by cliques.
Genome-Wide Association Analysis of High-Density Lipoprotein Cholesterol in the Population-Based KORA Study Sheds New Light on Intergenic Regions
Authors: Heid Iris M. , Boes Eva , Müller Martina , Kollerits Barbara , Lamina Claudia , Coassin Stefan , Gieger Christian , Döring Angela , Klopp Norman , Frikke-Schmidt Ruth , Tybj�rg-Hansen Anne , Brandstätter Anita , Luchner Andreas , Meitinger Thomas , Wichmann H.-Erich , Kronenberg Florian
Published: October 2008

Background—

High-density lipoprotein cholesterol (HDLC) is a strong risk factor for atherosclerosis and is assumed to be under considerable genetic control. We aimed to identify gene regions that influence HDLC levels by a genome-wide association analysis in the population-based KORA (Cooperative Health Research in the Region of Augsburg) study.

Methods and Results—

In KORA S3/F3 (n=1643), we analyzed 377 865 quality-checked single-nucleotide polymorphisms (SNPs; 500K, Affymetrix, Santa Clara, Calif), complemented by the publicly available genome-wide association results from the Diabetes Genetics Initiative (n=2631) and by replication data from KORA S4 (n=4037) and the Copenhagen City Heart Study (n=9205). Among the 13 SNPs selected from the KORA S3/F3 500K probability value list, 3 showed consistent associations in subsequent replications: 1 SNP 10 kb upstream of
CETP
(pooled probability value=8.5�10
−27
), 1 SNP approximately 40 kb downstream of
LIPG
(probability value=4.67�10
−10
), both independent of previously reported SNPs, and 1 from an already reported region of
LPL
(probability value=2.82�10
−11
). Bioinformatical analyses indicate a potential functional relevance of the respective SNPs.

Conclusions—

The present genome-wide association study identified 2 interesting HDLC-relevant regions upstream of
CETP
and downstream of
LIPG
. This draws attention to the importance of long-range effects of intergenic regions, which have been underestimated so far, and may impact future candidate-gene–association studies toward extending the region analyzed. Furthermore, the present study reinforced
CETP
and
LPL
as HDLC genes and thereby underscores the power of this type of genome-wide association approach to pinpoint associations of common polymorphisms with effects explaining as little as 0.5% of the HDLC variance in the general population.
Correlation of Peripheral-Blood Gene Expression With the Extent of Coronary Artery Stenosis
Authors: Wingrove James A. , Daniels Susan E. , Sehnert Amy J. , Tingley Whittemore , Elashoff Michael R. , Rosenberg Steven , Buellesfeld Lutz , Grube Eberhard , Newby L. Kristin , Ginsburg Geoffrey S. , Kraus William E.
Published: October 2008

Background—

The molecular pathophysiology of coronary artery disease (CAD) includes cytokine release and a localized inflammatory response within the vessel wall. The extent to which CAD and its severity is reflected by gene expression in circulating cells is unknown.

Methods and Results—

From an initial coronary catheterization cohort we identified 41 patients, comprising 27 cases with angiographically significant CAD and 14 controls without coronary stenosis. Whole-genome microarray analysis performed on peripheral-blood mononuclear cells yielded 526 genes with >1.3-fold differential expression (
P
<0.05) between cases and controls. Real-time polymerase chain reaction on 106 genes (the 50 most significant microarray genes and 56 additional literature genes) in an independent subset of 95 patients (63 cases, 32 controls) from the same cohort yielded 14 genes (
P
<0.05) that independently discriminated CAD state in a multivariable analysis that included clinical and demographic factors. From an independent second catheterization cohort, 215 patients were selected for real-time polymerase chain reaction–based replication. A case:control subset of 107 patients (86 cases, 21 controls) replicated 11 of the 14 multivariably significant genes from the first cohort. An analysis of the 14 genes in the entire set of 215 patients demonstrated that gene expression was proportional to maximal coronary artery stenosis (
P
<0.001 by ANOVA).

Conclusions—

Gene expression in peripheral-blood cells reflects the presence and extent of CAD in patients undergoing angiography.