bluuebunny/crossref_metadata_2025 huggingface dataset:
Topic taxonomy adaptation for group profiling
Authors: Tang Lei , Liu Huan , Zhang Jianping , Agarwal Nitin , Salerno John J.
Published: February 2008

A topic taxonomy is an effective representation that describes salient features of virtual groups or online communities. A topic taxonomy consists of topic nodes. Each internal node is defined by its vertical path (i.e., ancestor and child nodes) and its horizonal list of attributes (or terms). In a text-dominant environment, a topic taxonomy can be used to flexibly describe a group's interests with varying granularity. However, the stagnant nature of a taxonomy may fail to timely capture the dynamic change of a group's interest. This article addresses the problem of how to adapt a topic taxonomy to the accumulated data that reflects the change of a group's interest to achieve dynamic group profiling. We first discuss the issues related to topic taxonomy. We next formulate taxonomy adaptation as an optimization problem to find the taxonomy that best fits the data. We then present a viable algorithm that can efficiently accomplish taxonomy adaptation. We conduct extensive experiments to evaluate our approach's efficacy for group profiling, compare the approach with some alternatives, and study its performance for dynamic group profiling. While pointing out various applications of taxonomy adaption, we suggest some future work that can take advantage of burgeoning Web 2.0 services for online targeted marketing, counterterrorism in connecting dots, and community tracking.
Finding hierarchical heavy hitters in streaming data
Authors: Cormode Graham , Korn Flip , Muthukrishnan S. , Srivastava Divesh
Published: February 2008

Data items that arrive online as streams typically have attributes which take values from one or more hierarchies (time and geographic location, source and destination IP addresses, etc.). Providing an aggregate view of such data is important for summarization, visualization, and analysis. We develop an aggregate view based on certain organized sets of large-valued regions (“heavy hitters”) corresponding to hierarchically discounted frequency counts. We formally define the notion of
hierarchical heavy hitters
(HHHs). We first consider computing (approximate) HHHs over a data stream drawn from a single hierarchical attribute. We formalize the problem and give deterministic algorithms to find them in a single pass over the input.

In order to analyze a wider range of realistic data streams (e.g., from IP traffic-monitoring applications), we generalize this problem to multiple dimensions. Here, the semantics of HHHs are more complex, since a “child” node can have multiple “parent” nodes. We present online algorithms that find approximate HHHs in one pass, with provable accuracy guarantees. The product of hierarchical dimensions forms a mathematical lattice structure. Our algorithms exploit this structure, and so are able to track approximate HHHs using only a small, fixed number of statistics per stored item, regardless of the number of dimensions.

We show experimentally, using real data, that our proposed algorithms yields outputs which are very similar (virtually identical, in many cases) to offline computations of the exact solutions, whereas straightforward heavy-hitters-based approaches give significantly inferior answer quality. Furthermore, the proposed algorithms result in an order of magnitude savings in data structure size while performing competitively.
Learning correlations using the mixture-of-subsets model
Authors: Somaiya Manas , Jermaine Christopher , Ranka Sanjay
Published: February 2008

Using a mixture of random variables to model data is a tried-and-tested method common in data mining, machine learning, and statistics. By using mixture modeling it is often possible to accurately model even complex, multimodal data via very simple components. However, the classical mixture model assumes that a data point is generated by a single component in the model. A lot of datasets can be modeled closer to the underlying reality if we drop this restriction. We propose a probabilistic framework, the
mixture-of-subsets (MOS) model
, by making two fundamental changes to the classical mixture model. First, we allow a data point to be generated by a set of components, rather than just a single component. Next, we limit the number of data attributes that each component can influence. We also propose an EM framework to learn the MOS model from a dataset, and experimentally evaluate it on real, high-dimensional datasets. Our results show that the MOS model learned from the data represents the underlying nature of the data accurately.
Arithmetic on a distributed-memory quantum multicomputer
Authors: Meter Rodney Van , Munro W. J. , Nemoto Kae , Itoh Kohei M.
Published: February 2008

We evaluate the performance of quantum arithmetic algorithms run on a distributed quantum computer (a quantum multicomputer). We vary the node capacity and I/O capabilities, and the network topology. The tradeoff of choosing between gates executed remotely, through “teleported gates” on entangled pairs of qubits (telegate), versus exchanging the relevant qubits via quantum teleportation, then executing the algorithm using local gates (teledata), is examined. We show that the teledata approach performs better, and that carry-ripple adders perform well when the teleportation block is decomposed so that the key quantum operations can be parallelized. A node size of only a few logical qubits performs adequately provided that the nodes have two transceiver qubits. A linear network topology performs acceptably for a broad range of system sizes and performance parameters. We therefore recommend pursuing small, high-I/O bandwidth nodes and a simple network. Such a machine will run Shor's algorithm for factoring large numbers efficiently.
Virtual machine showdown
Authors: Shi Yunhe , Casey Kevin , Ertl M. Anton , Gregg David
Published: February 2008

Virtual machines (VMs) enable the distribution of programs in an architecture-neutral format, which can easily be interpreted or compiled. A long-running question in the design of VMs is whether a stack architecture or register architecture can be implemented more efficiently with an interpreter. We extend existing work on comparing virtual stack and virtual register architectures in three ways. First, our translation from stack to register code and optimization are much more sophisticated. The result is that we eliminate an average of more than 46% of executed VM instructions, with the bytecode size of the register machine being only 26% larger than that of the corresponding stack one. Second, we present a fully functional virtual-register implementation of the Java virtual machine (JVM), which supports Intel, AMD64, PowerPC and Alpha processors. This register VM supports inline-threaded, direct-threaded, token-threaded, and switch dispatch. Third, we present experimental results on a range of additional optimizations such as register allocation and elimination of redundant heap loads. On the AMD64 architecture the register machine using switch dispatch achieves an average speedup of 1.48 over the corresponding stack machine. Even using the more efficient inline-threaded dispatch, the register VM achieves a speedup of 1.15 over the equivalent stack-based VM.
Object co-location and memory reuse for Java programs
Authors: Yu Zoe C. H. , Lau Francis C. M. , Wang Cho-Li
Published: February 2008

We introduce a new memory management system, STEMA, which can improve the execution time of Java programs. STEMA detects prolific types on-the-fly and co-locates their objects in a special memory space which supports reuse of memory. We argue and show that memory reuse and co-location of prolific objects can result in improved cache locality, reduced memory fragmentation, reduced GC time, and faster object allocation. We evaluate STEMA using 16 benchmarks. Experimental results show that STEMA performs 2.7%, 4.0%, and 8.2% on average better than MarkSweep, CopyMS, and SemiSpace.
Hiding the misprediction penalty of a resource-efficient high-performance processor
Authors: Golander Amit , Weiss Shlomo
Published: February 2008

Misprediction is a major obstacle for increasing speculative out-of-order processors performance. Performance degradation depends on both the number of misprediction events and the recovery time associated with each one of them. In recent years a few checkpoint based microarchitectures have been proposed. In comparison with ROB-based processors, checkpoint processors are scalable and highly resource efficient. Unfortunately, in these proposals the misprediction recovery time is proportional to the instruction queue size.

In this paper we analyze methods to reduce the misprediction recovery time. We propose a new register file management scheme and techniques to selectively flush the instruction queue and the load store queue, and to isolate deeply pipelined execution units. The result is a novel checkpoint processor with Constant misprediction RollBack time (CRB). We further present a streamlined, cost-efficient solution, which saves complexity at the price of slightly lower performance.
A Structure-Based Model for Chinese Organization Name Translation
Authors: Chen Yufeng , Zong Chengqing
Published: February 2008

Named entity (NE) translation is a fundamental task in multilingual natural language processing. The performance of a machine translation system depends heavily on precise translation of the inclusive NEs. Furthermore, organization name (ON) is the most complex NE for translation among all the NEs. In this article, the structure formulation of ONs is investigated and a hierarchical structure-based ON translation model for Chinese-to-English translation system is presented.

First, the model performs ON chunking; then both the translation of words within chunks and the process of chunk-reordering are achieved by synchronous context-free grammar (CFG). The CFG rules are extracted from bilingual ON pairs in a training program.

The main contributions of this article are: (1) defining appropriate chunk-units for analyzing the internal structure of Chinese ONs; (2) making the chunk-based ON translation feasible and flexible via a hierarchical CFG derivation; and (3) proposing a training architecture to automatically learn the synchronous CFG for constructing ONs with chunk-units from aligned bilingual ON pairs. The experiments show that the proposed approach translates the Chinese ONs into English with an accuracy of 93.75% and significantly improves the performance of a baseline statistical machine translation (SMT) system.
Toward a Usage-Based Security Framework for Collaborative Computing Systems
Authors: Zhang Xinwen , Nakae Masayuki , Covington Michael J. , Sandhu Ravi
Published: February 2008

Collaborative systems such as Grids provide efficient and scalable access to distributed computing capabilities and enable seamless resource sharing between users and platforms. This heterogeneous distribution of resources and the various modes of collaborations that exist between users, virtual organizations, and resource providers require scalable, flexible, and fine-grained access control to protect both individual and shared computing resources. In this article we propose a usage control (UCON) based security framework for collaborative applications, by following a layered approach with policy, enforcement, and implementation models, called the PEI framework. In the policy model layer, UCON policies are specified with predicates on subject and object attributes, along with system attributes as conditional constraints and user actions as obligations. General attributes include not only persistent attributes such as role and group memberships but also mutable usage attributes of subjects and objects. Conditions in UCON can be used to support context-based authorizations in ad hoc collaborations. In the enforcement model layer, our novel framework uses a hybrid approach for subject attribute acquisition with both push and pull modes. By leveraging attribute propagations between a centralized attribute repository and distributed policy decision points, our architecture supports decision continuity and attribute mutability of the UCON policy model, as well as obligation evaluations during policy enforcement. As a proof-of-concept, we implement a prototype system based on our proposed architecture and conduct experimental studies to demonstrate the feasibility and performance of our approach.
XACML Policy Integration Algorithms
Authors: Mazzoleni Pietro , Crispo Bruno , Sivasubramanian Swaminathan , Bertino Elisa
Published: February 2008

XACML is the OASIS standard language specifically aimed at the specification of authorization policies. While XACML fits well with the security requirements of a single enterprise (even if large and composed by multiple departments), it does not address the requirements of virtual enterprises in which several autonomous subjects collaborate by sharing their resources to provide better services to customers. In this article we highlight such limitation, and we propose an XACML extension, the policy integration algorithms, to address them. In the article we also present the implementation of a system that makes use of the policy integration algorithms to securely replicate information in a P2P-like environment. In our solution, the data replication process considers the policies specified by both the owners of the data shared and the peers sharing data storage.
20 years on
Authors: Dodd Robert
Published: February 2008

In 2008 the Dexter Model of Hypertext will be 20 years old. Even after 20 years, the structure of Web documents, and the syntax we use to describe them and their relations to one another is still noticeably bound up with that 1980's view of content navigation. With the W3C having launched a consultation exercise on HTML 5, and a browser war imminent over the future of ECMA/Java Script, it is time to reconsider what the discipline of accessibility requires of a hypertext model. This article considers both the original Dexter Model, and, briefly, the related Amsterdam Model of Hypermedia, in terms of the needs of assistive technology, and proposes an alternative, extended view of Hypertext of which the original Dexter Model can be considered a subset.
Mobile web
Authors: Harper Simon
Published: February 2008

Tagline: Reusing the lessons learnt in achieving Web accessibility can speed the Mobile Web to fruition.
K42
Authors: Wisniewski Robert W. , da Silva Dilma , Auslander Marc , Krieger Orran , Ostrowski Michal , Rosenburg Bryan
Published: February 2008

We started the K42 project more than ten years ago with the ambitious goal of developing an operating system for next-generation hardware that would be widely valued and thus widely used. Based on the premise that current operating systems were not designed to be scalable, customizable, or maintainable, we set forth to rectify that by applying proven techniques from other disciplines to operating systems and by developing additional innovative mechanisms.

Now, ten year later, K42 is used by ten or so universities and national labs for research purposes, not ten million information technology departments desiring better everyday computing platforms. As a presentation to the primary operating systems community we provide an examination from two different perspectives as to what went right and what went wrong. First, we concentrate on what technology worked well and why, and what technology failed or caused undue difficulties, and why. Second, based on that experience, we provide our thoughts on the state and direction of the OS community at large.

To be clear, this paper is neither a results paper nor an overview paper; we refer to other papers for background material. Rather, it is an exploration by researchers with experience with at least six different previous operating systems of the merit of technologies investigated in K42, and an extrapolation of the implications of that experience to the wider operating system community.
The Caernarvon secure embedded operating system
Authors: Toll David C. , Karger Paul A. , Palmer Elaine R. , McIntosh Suzanne K. , Weber Sam
Published: February 2008

The Caernarvon operating system was developed to demonstrate that a high assurance system for smart cards was technically feasible and commercially viable. The entire system has been designed to be evaluated under the Common Criteria at EAL7, the highest defined level of assurance.

Historically, smart card processors have not supported the hardware protection features necessary to separate the OS from the applications, and one application from another. The Caernarvon OS has taken advantage of the first smart card processors with such features to be the first smart card OS to provide this kind of protection. Even when compared with conventional systems where the hardware protection is routine, the Caernarvon OS is noteworthy, because of the EAL7 assurance.

This approach facilitated implementation of a formally specified, mandatory security policy providing multi-level security (MLS) suitable for both government agencies and commercial users. The mandatory security policy requires effective authentication of its users that is independent of applications. For this reason, the Caernarvon OS also contains a privacy-preserving, two-way authentication protocol integrated with the Mandatory Security Policy.

The Caernarvon OS includes a strong cryptographic library that has been separately certified under the Common Criteria at EAL5+ for use with other systems. The Caernarvon OS implements a secure method for downloading trusted and untrusted application software and data in the field, with the assumption that all applications are potentially hostile. While the initial platform for the operating system was smart cards, the design could also be used in other embedded devices, such as USB tokens, PDAs, cell phones, etc.
TVDc
Authors: Berger Stefan , Cáceres Ramón , Pendarakis Dimitrios , Sailer Reiner , Valdez Enriquillo , Perez Ronald , Schildhauer Wayne , Srinivasan Deepa
Published: February 2008

Virtualization technology is becoming increasingly common in datacenters, since it allows for collocation of multiple workloads, consisting of operating systems, middleware and applications, in different virtual machines (VMs) on shared physical hardware platforms. However, when coupled with the ease of VM migration, this trend increases the potential surface for security attacks. Further, the simplified management of VMs, including creation, cloning and migration, makes it imperative to monitor and guarantee the integrity of software components running within VMs.

This paper presents the IBM Trusted Virtual Datacenter (TVDc) technology developed to address the need for strong isolation and integrity guarantees, thus significantly enhancing security and systems management capabilities, in virtualized environments. It signifies the first effort to incorporate trusted computing technologies directly into virtualization and systems management software. We present and discuss various components that constitute TVDc: the Trusted Platform Module (TPM), the virtual TPM, the IBM hypervisor security architecture (sHype) and the associated systems management software.
Panache
Authors: Ananthanarayanan R. , Eshel M. , Haskin R. , Naik M. , Schmuck F. , Tewari R.
Published: February 2008

Panache is a scalable, high-performance, remote file data caching solution integrated with the GPFS cluster file system. It leverages the inherent scalability of GPFS to provide a multi-node, consistent cache of data exported by a remote file system cluster. Panache exploits the soon-to-be standard pNFS protocol to move data in parallel from the remote file cluster. Furthermore, it provides a POSIX compliant file system interface making the cache completely transparent to applications. Panache can mask the fluctuating wide-area-network latencies and outages by supporting asynchronous and disconnected-mode operations. It allows concurrent updates to be made at the cache and at the remote cluster and synchronizes them by using conflict detection techniques to flag and handle conflicts. To maintain commercial viability, Panache relies on open standards for high-performance file serving and does not require any proprietary hardware or software to be deployed at the remote cluster. In this paper we present the overall architecture of Panache and its key features.
Flipstone
Authors: Banikazemi Mohammad , Hafner Jim , Belluomini Wendy , Rao KK , Poff Dan , Abali Bulent
Published: February 2008

The cost of managing storage systems has become one of the significant expense items in data centers. In this paper, we discuss the design and implementation of Flipstone, a new storage system with reduced storage management cost. Flipstone provides fail-in-place and deferred maintenance by aggregating large number of off-the-shelf, inexpensive storage systems. We show a significant improvement in total cost of ownership of storage systems by reducing the number of service calls when Flipstone is used.
Project Kittyhawk: building a global-scale computer
Authors: Appavoo Jonathan , Uhlig Volkmar , Waterland Amos
Published: February 2008

This paper describes Project Kittyhawk, an undertaking at IBM Research to explore the construction of a next-generation platform capable of hosting many simultaneous web-scale workloads. We hypothesize that for a large class of web-scale workloads the Blue Gene/P platform is an order of magnitude more efficient to purchase and operate than the commodity clusters in use today. Driven by scientific computing demands the Blue Gene designers pursued an aggressive system-on-a-chip methodology that led to a scalable platform composed of air-cooled racks. Each rack contains more than a thousand independent computers with highspeed interconnects inside and between racks.

We postulate that the same demands of efficiency and density apply to web-scale platforms. This project aims to develop the system software to enable Blue Gene/P as a generic platform capable of being used by heterogeneous workloads. We describe our firmware and operating system work to provide Blue Gene/P with generic system software, one of the results of which is the ability to run thousands of heterogeneous Linux instances connected by TCP/IP networks over the high-speed internal interconnects.
Holistic aggregate resource environment
Authors: Van Hensbergen Eric , Forsyth Charles , McKie Jim , Minnich Ron
Published: February 2008

Within a few short years, we can expect to be dealing with multi-million-thread programs running on million-core systems [16]. This will no doubt stress the contemporary HPC software model which was developed in a time when 512 cores was a large number. Historical approaches have been further challenged by the increased desire of developers and end users for supercomputer light weight kernels (LWKs) to support the same environment, libraries, and tools as their desktops. As a result, the emerging workloads of today are far more sophisticated than those of the last two decades when much of the HPC infrastructure was developed, and feature the use of scripting environments such as Python, dynamic libraries, and complex multi-scale physics frameworks. Complicating this picture is the overwhelming management, monitoring and reliability problem created by the huge number of nodes in a system of that magnitude.

We believe that a re-evaluation and exploration of distributed system principals is called for in order to address the challenges of ultrascale. To that end we will be evaluating and extending the Plan 9 [21] distributed system on the largest machines available to us, namely the BG/L [28] and BG/P [10] supercomputers. We have chosen Plan 9 based on our previous experiences with it in combination with previous research [17] which determined Plan 9 was a "right weight kernel", balancing trade offs between LWKs and more general purpose operating systems such as Linux. To deal with issues of scale, we plan on leveraging the use of the high-performance interconnects by system services as well as exploring aggregation as more of a first-class system construct -- providing dynamic hierarchical organization and management of all resources. Our plan is to evaluate the viability of these concepts at scale as well as create an alternative development and execution environment which compliments the features and capabilities of the existing system software and run time options. Our intent is to broaden the application base as well as make the system as a whole more approachable to a larger class of developers and end-users.
A database scale-out solution for emerging write-intensive commercial workloads
Authors: Ge Yi , Wang Chen , Shen Xiaowei , Young Honesty
Published: February 2008

Among the increasing number of online businesses, a series of write-intensive commercial workloads are emerging recently on the Internet. These workloads generate many more write transactions on the backend database than read transactions. Most of such workloads require the database to handle high-volume write transactions in real-time. Based on the observation on the workloads, this paper proposes a multi-tier database scale-out architecture with the write caching technology. Our preliminary result shows that the database scale-out architecture can handle extremely high-volume write transactions with excellent scalability.
Specialized execution environments
Authors: Butrico Maria , Da Silva Dilma , Krieger Orran , Ostrowski Michal , Rosenburg Bryan , Tsafrir Dan , Van Hensbergen Eric , Wisniewski Robert W. , Xenidis Jimi
Published: February 2008

Virtualization has become popular (again) as a means of consolidating multiple operating systems (OSes) onto a smaller set of hardware resources. The roles of OSes in such environments have changed. Whereas normally an OS provides balance between the demands of application and hardware support, in the world of virtualization it can be beneficial to split these roles. One OS may support a particular application set and use other OSes to interact with physical hardware. The hypervisor, or virtualization layer, provides communication facilities for the inter-OS communication needed to support such a deployment model.
GWiQ-P
Authors: Karmon Kfir , Liss Liran , Schuster Assaf
Published: February 2008

Mega grids span several continents and may consist of millions of nodes and billions of tasks executing at any point in time. This setup calls for scalable and highly available resource utilization control that adapts itself to dynamic changes in the grid environment as they occur. In this paper, we address the problem of enforcing upper bounds on the consumption of grid resources. We propose a grid-wide quota enforcement system, called GWiQ-P. GWiQ-P is light-weight, and in practice is infinitely scalable, satisfying concurrently any number of resource demands, all within the limits of a global quota assigned to each user. GWiQ-P adapts to dynamic changes in the grid as they occur, improving future performance by means of improved locality. This improved performance does not impair the system's ability to respond to current requests, tolerate failures, or maintain the allotted quota levels.
Probabilistic lossy counting
Authors: Dimitropoulos Xenofontas , Hurley Paul , Kind Andreas
Published: February 2008

Knowledge of the largest traffic ows in a network is important for many network management applications. The problem of finding these ows is known as the heavy-hitter problem and has been the subject of many studies in the past years. One of the most efficient and well-known algorithms for finding heavy hitters is lossy counting [29].

In this work we introduce probabilistic lossy counting (PLC), which enhances lossy counting in computing network traffic heavy hitters. PLC uses on a tighter error bound on the estimated sizes of traffic ows and provides probabilistic rather than deterministic guarantees on its accuracy. The probabilistic-based error bound substantially improves the memory consumption of the algorithm. In addition, PLC reduces the rate of false positives of lossy counting and achieves a low estimation error, although slightly higher than that of lossy counting

We compare PLC with state-of-the-art algorithms for finding heavy hitters. Our experiments using real traffic traces find that PLC has 1) between 34.4% and 74% lower memory consumption, 2) between 37.9% and 40.5% fewer false positives than lossy counting, and 3) a small estimation error.
Cold topics in networking
Authors: Crowcroft Jon
Published: February 2008

A major contribution to global warming has been the number of new workshops publishing proceedings with the prefix hot. In this article, I propose that we counter this trend in an attempt to remain carbon neutral with a set of 'anti-workshops' on cold topics.

We suggest a number of heuristics for detecting when a topic has gone cold, and give some examples of the application of these heuristics. Of course, some cold topics warm up again, and so there is a risk of over dampening in our heuristic. Over a long period, dynamic equilibrium should be assured, but from time to time, our scheme may prejudice against surprising results in boring areas of communications research. Nevertheless, it may leave room for more surprising results in interesting areas of research, which cannot be a bad thing
You must be joking...
Authors: Faloutsos Michalis
Published: February 2008

The goal of this column this time was to address major scientific issues and propose novel scientific methods for doing the same thing under different names. However, it turned out to be too complicated as it required mastery of the english alphabet. Then, I had an epiphany (greek word): Why propose something new, when you can complain about something that already exists? I think I am turning into an angry old man prematurely.
The occupational culture of IS/IT personnel within organizations
Authors: Guzman Indira R. , Stam Kathryn R. , Stanton Jeffrey M.
Published: February 2008

As organizations' reliance on information technology (IT) continues to grow, the information technology personnel who support end users play an increasingly important role in the proper functioning of those organizations. In the present study, we interviewed information technology personnel (N=32) as well as other employees (N=89) to examine their intra-group and inter-group communications and assess the existence and importance of the occupational culture of IT personnel within organizations. We applied Trice's Occupational Subculture theoretical framework (1993) to examine the characteristics of the occupational culture of IT personnel and its relationships with other type of personnel within organizations. The results of our study suggest that IT personnel have established a distinct occupational culture within organizations, characterized, for example, by the use of technical jargon, primary value of technical knowledge, extreme and unusual demands on people in the profession related to the constant change of IT, feelings of superiority and a general lack of formal rules. Conflicts between IT occupational subcultures and other extant subcultures arise from cultural differences
Electrodeposition of n-type Cuprous Oxide Thin Films
Authors: Siripala Withana P.
Published: February 2008

Cuprous oxide (Cu2O) is generally a p-type semiconductor material due to the Cu ion vacancies exist in the crystal lattice. The technique of electrodeposition provides the possibility of depositing Cu2O thin films resulting n-type photoresponses in solar cell devices. By maintaining pH values of the depositing aqueous acetate bath in an appropriate range, Cu2O thin films can be potentiostatically electrodeposited. Single phase Cu2O polycrystalline films can be obtained using this technique. The n-type behavior and the quality of the Cu2O films produced by this technique are demonstrated by the photocurrent, capacitance-voltage, SEM and XRD measurements. Existence of oxygen vacancies in the n-Cu2O films is evident from the photoluminescence measurements. Possibility of using these films in low cost solar cell devices is demonstrated after establishing the n-Cu2O/p-CuxS hetero junction by sulphiding Cu2O thin films.
There and Back Again - An Electrochemical Engineer's Tale
Authors: St-Pierre Jean
Published: February 2008

The author's persistent challenges encountered during his electrochemical energy conversion industrial career include technical and research management knowledge expansion, and adaptation to change. Useful methods to overcome these challenges are briefly discussed and include pro-active learning and avoiding the loss of focus on long term career goals. Knowledge of intellectual property matters and interviewing skills are also mentioned as essential for an industrial career. Some of these topics are also shared by other career paths, such as research at universities or national laboratories, but are not similarly experienced either due to cultural or structural differences. More importantly, the author did not learn any of these topics, most of them considered soft skills, during his university student years.
Remarks to the Leadership and Entrepreneurship in Electrochemical Engineering Symposium of the Electrochemical Society
Authors: Mara Patrick D.
Published: February 2008

Abstract not Available.
Dissolution and Swelling Behaviour of Plasma-Polymerized Polyethylene Glycol-Like Hydrogel Films for use as Drug Delivery Reservoirs
Authors: Pathak Shantanu C. , Hess Dennis W.
Published: February 2008

Plasma-polymerized polyethylene glycol-like (PEG) thin films were deposited for use as reservoirs in drug delivery applications. Radio frequency power, reactor pressure and deposition temperature were varied in a parallel-plate plasma reactor to obtain two films with different relative crosslink densities, which were established by refractive indices. Variation of crosslink density allowed the tailoring of film swelling and chemical stability in aqueous environments. Film thicknesses and optical properties were measured with variable angle spectroscopic ellipsometry. In-situ ellipsometry dynamically monitored reversible film thickness changes in the presence of water vapor. Highly crosslinked films (deposited at elevated power and temperature and reduced pressure) swelled ~15% and relatively low crosslink density swelled ~70%. Electrophoretic immobilization tested these PEG films as storage materials for drugs. Negatively charged green fluorescent protein (GFP) was used as a model drug and fluorescence marker. Relatively highly crosslinked films showed enhanced incorporation of drifted GFP relative to incorporation by diffusion.
Monosaccharide Sensing Based on Multivariate Analysis of Voltammetric Data Acquired from a Pt:Ru Electrode Array
Authors: Steen William A. , Stork Christopher , Wall Frederick
Published: February 2008

Predictive models for concentration of mixed monosaccharide solutions were developed based on combinatorial electrochemistry and chemometric techniques. The columns on a 10x10 array of Pt wires were electrodeposited with 10 different Pt:Ru alloys. Cyclic voltammograms were performed in 1M solutions of glucose, fructose, and galactose. Principal component analysis was applied to the resulting data sets; a scores plot allowed classification of the pure solutions. Fifteen solutions containing the three sugars in concentrations ranging from 10-1000mM were used to train partial least squares regression models. Twelve independent test solutions were also prepared in similar concentration ranges. For these test samples, root-mean-squared-error-of- predictions (RMSEPs) of 142mM and 120mM were obtained for glucose and galactose. The RMSEP for fructose between 10- 500mM was 128mM, but nonlinearities caused the model to fail at higher concentratio ns. These results demonstrate that with only a few electrode variants it is possible to differentiate monosaccharides in a semi-quantitative fashion.
Comparative Study of SnO2- and In2O3-based Ozone Sensors
Authors: Korotcenkov Ghenadii , Stetter Joseph R.
Published: February 2008

In this paper we present the results of comparative study of ozone sensors that are designed using undoped SnO2 and In2O3 films. These two metal oxides are the mostly studied materials and a critical comparison of their response parameters is very important for the determination of the practical prospects of these materials in real-world applications.
Investigating the Stability and Accuracy of the Phase Response for NOx Sensing 5% Mg-modified LaCrO3
Authors: Murray Erica P. , Novak Robert , Kubinski David , Soltis Richard , Visser Jaco , Woo Leta , Martin Louis , Glass Robert
Published: February 2008

Impedance spectroscopy measurements were carried out on LaCr0.95Mg0.05O3 (LCM) asymmetric interdigitated electrodes supported on fully stabilized 8-mol% Y2O3-stabilized ZrO2 (YSZ) electrolytes. Experiments were carried out using 0 - 50 ppm NOx, 5 - 15% O2 with N2 as the balance, over temperatures ranging from 600 - 700C. AC measurements taken at a constant frequency between 1 - 100 Hz indicated the phase response of the sensor was less sensitive to fluctuations in the O2 concentration and the baseline drift was limited. Specific frequencies were observed where the sensor response was essentially temperature independent.
Nanotopography Development on Silicon Electrodes by Analysis of Brewster Angle Real-Time Spectroscopy
Authors: Lublow Michael , Lewerenz H. J.
Published: February 2008

The nanostructure formation of n-type silicon photoelectrodes in fluoride containing solutions was investigated by in-situ Brewster angle reflectometry (BAR) and atomic force microscopy (AFM). The corrugation process near the first current maximum of the divalent/tetravalent dissolution regime preserves the (111) surface lattice symmetry as proven by auto-correlation analysis of corresponding AFM images: the structure alignment is related to the terrace orientation of the original H- terminated Si-samples. The observed cathodic shift of the open circuit potential (OCP) for increased light intensities (~240 mV for intensities between 1 and 40 mW/cm2) allowed further shaping of the nanostructures: it was possible to invoke alternately divalent and tetravalent paths of the silicon dissolution process at a constant potential. Oxidation in the tetravalent dissolution regime was observed to affect statistically rough areas faster than the nanostructu res. As a result, an increase of the aspect ratio of 40%-60% could be achieved.
Ultra-Low Drift Voltage by Using Gate Voltage Control in Oxide-Based Gate ISFET
Authors: Chang K. M. , Chao Kuo-Yi , Hsu H. Y. , Huang M. C.
Published: February 2008

In this study, a simple and cheap way to solve the drift problem is presented which describes the relation of drift and gate voltage. Constant various gate voltages are biased in sensing layers with reference electrode. It obviously shows a strong relation of gate drifts and gate stress voltages. When the gate voltage is controlled as 0.5 V, the drift voltage of SiO2 gate ISFET will decrease from 56.12 to 2.94 mV in ten hours measurement. The improvement of drift voltage reaches 94.8%. When the gate voltage is controlled as -1 V, the drift voltage of ZrO2 gate ISFET will also decrease from -57.94 to 0.76 mV. The improvement of drift voltage reaches 98.7%. This may result from the gate electric field affecting the ions to diffusive into the gate insulator. By this way, we can commercialize the ISFET with a very low drift rate in a simple way.
Electrochemical Studies On Corrosion of Alloy 22 Weld And Metal In Aqueous KCl and Na2SO4 Electrolytes
Authors: Parmar Anil , Varma Ravi
Published: February 2008

Long term durability of alloy 22 weld between the lid and the alloy 22 metal container with High Level Nuclear Waste, in the corrosive environment of Yucca Mountain Repository (YMR) for thousands of years remains a challenge. The different modes of corrosion and rates of corrosion of the alloy 22 weld and the alloy 22 metal in the aqueous electrolytes were electrochemically studied to provide a comparison of the relative propensity of the weld and the metal to corrode in moist chloride environment. Potentiodynamic (PD) Polarization data along with analytical techniques and the Stern Gerlach theory were used to estimate rates of corrosion for both alloy 22 weld and the alloy 22 metal. The studies reported here raise very serious concerns on the long term durability of the welded shut containers in the YMR environment.
Copper ECD Process Control by Means of Electroanalysis Combined with Multi-way Data Decomposition Chemometric Techniques
Authors: Jaworski Aleksander , Wikiel Hanna , Wikiel Kazimierz
Published: February 2008

The Real Time Analyzer (RTA) utilizing DC- and AC- voltammetric techniques is an in-situ, on-line monitoring system that allows for a full chemical analysis of different plating solutions. The presentation focuses on the application of numerous statistical methods: design of experiment (DOE), SIMCA-based modeling power (providing information about signal-to-noise ratio and relevancy of the chosen part of signal in the model) and latent factor-analysis-based multi-way data multivariate regression resulting in a reliable and accurate calibration model. These steps include: training set design, determination of the portion(s) of the voltammetric signal(s) to be taken for calculations (modeling power coupled with least squares regression (LSR)). The calibration model is calculated employing tri-linear Partial Least Squares (tri-PLS1) latent factor-wise regression/decomposition technique. The tri-PLS1 method is capable of simultaneous compressing , extracting information, and regressing three dimensional voltammetric data arrays created using several, various voltammetric curves characterizing each sample solution. The calibration is validated using cross-validation and external validation.
Parameter Evaluation of ORR at a RRDE
Authors: Dong Qingbo , White Ralph E.
Published: February 2008

The humps and plateaus in the ring polarization curves for oxygen reduction reaction at a rotating ring disk (smooth platinum) electrode in 0.5 M sulfuric acid solution and 0.5 M perchloric acid solution were analyzed. The oxygen reduction is assumed to take a 4-electron transfer pathway in majority, and two different 2-electron transfer pathways leading to peroxide generation in minority. The exchange current densities and transfer coefficients of the above three reactions were evaluated by the Gauss-Newton nonlinear parameter estimation technique with experimental data. The oxygen concentrations in the electrolytes were also evaluated as variables since tend to cause errors in the experiments. The fits between experimental results and regression results are with fair quality and support the proposed reaction mechanism.
The Investigation of Au/Pd-Ni/Ni Plating for Electrical Contacts
Authors: Hiramoto Osamu
Published: February 2008

Au plated contacts often experience contact failures because of a contact resistance increased due to corrosion. In this paper, the plating technology which uses a Pd-Ni alloy as a middle layer of plating is shown. It can provide a long- lasting, stable connection between contacts that are rubbed against each other repeatedly.
Dynamics of enterocyte tight junctions: effect of experimental colitis and two different anti-TNF strategies
Authors: Fries Walter , Muja Carmelo , Crisafulli Carmela , Cuzzocrea Salvatore , Mazzon Emanuela
Published: February 2008

An alteration of the intestinal barrier is considered to represent an early step in pathogenesis of Crohn's disease. The integrity of intestinal barrier function is guaranteed among other factors by enterocyte tight junction (TJ) proteins. Clinical and experimental data indicate the TNF-α to be the major responsible factor for these defects. In the present study we investigated the very early effects of DNBS-ethanol colitis on ileal enterocyte TJ proteins [occludin, zonula occludens-1 (ZO-1), claudin-2] in controls, mice treated with infliximab (IFX) or with etanercept (ETC), and in knockout mice for the TNF-α receptor 1 (TNFR-1−/−). Circulating TNF-α levels were effectively reduced by IFX and ETC ( P < 0.01, both) at 3 and at 6 h. DNBS colitis induced disappearance of occludin and ZO-1 from enterocyte cell-cell contact, whereas claudin-2, absent under control conditions, appeared in the ileal epithelium. These alterations were prevented equally by both treatments, IFX and ETC, and in TNFR-1−/− animals. DNBS colitis induced a very rapid loss of occludin and ZO-1 from ileal TJ together with an upregulation of claudin-2. Our data are consistent with the hypothesis that TNF-α is involved in early TJ rearrangement and that its effects are mediated through TNFR-1. Despite clinical differences, both anti-TNF treatments were equally effective in the present setting.
Role of NHE1 in calcium signaling and cell proliferation in human CNS pericytes
Authors: Nakamura Kuniyuki , Kamouchi Masahiro , Kitazono Takanari , Kuroda Junya , Matsuo Ryu , Hagiwara Noriko , Ishikawa Eiichi , Ooboshi Hiroaki , Ibayashi Setsuro , Iida Mitsuo
Published: February 2008

The central nervous system (CNS) pericytes play an important role in brain microcirculation. Na+/H+ exchanger isoform 1 (NHE1) has been suggested to regulate the proliferation of nonvascular cells through the regulation of intracellular pH, Na+, and cell volume; however, the relationship between NHE1 and intracellular Ca2+, an essential signal of cell growth, is still not known. The aim of the present study was to elucidate the role of NHE1 in Ca2+ signaling and the proliferation of human CNS pericytes. The intracellular Ca2+ concentration was measured by fura 2 in cultured human CNS pericytes. The cells showed spontaneous Ca2+ oscillation under quasi-physiological ionic conditions. A decrease in extracellular pH or Na+ evoked a transient Ca2+ rise followed by Ca2+ oscillation, whereas an increase in pH or Na+ did not induce the Ca2+ responses. The Ca2+ oscillation was inhibited by an inhibitor of NHE in a dose-dependent manner and by knockdown of NHE1 by using RNA interference. The Ca2+ oscillation was completely abolished by thapsigargin. The proliferation of pericytes was attenuated by inhibition of NHE1. These results demonstrate that NHE1 regulates Ca2+ signaling via the modulation of Ca2+ release from the endoplasmic reticulum, thus contributing to the regulation of proliferation in CNS pericytes.
Enhancement of the adolescent murine musculoskeletal system using low-level mechanical vibrations
Authors: Xie Liqin , Rubin Clinton , Judex Stefan
Published: February 2008

Mechanical signals are recognized as anabolic to both bone and muscle, but the specific parameters that are critical to this stimulus remain unknown. Here we examined the potential of extremely low-magnitude, high-frequency mechanical stimuli to enhance the quality of the adolescent musculoskeletal system. Eight-week-old female BALB/cByJ mice were divided into three groups: baseline controls (BC, n = 8), age-matched controls (AC, n = 12), and whole body vibration (WBV, n = 12) at 45 Hz (0.3 g) for 15 min/day. Following 6 wk of WBV, bone mineralizing surfaces of trabeculae in the proximal metaphysis of the tibia were 75% greater ( P < 0.05) than AC, while osteoclast activity was not significantly different. The tibial metaphysis of WBV mice had 14% greater trabecular bone volume ( P < 0.05) than AC, while periosteal bone area, bone marrow area, cortical bone area, and the moments of inertia of this region were all significantly greater (up to 29%, P < 0.05). The soleus muscle also realized gains by WBV, with total cross-sectional area as well as type I and type II fiber area as much as 29% greater ( P < 0.05) in mice that received the vibratory mechanical stimulus. The small magnitude and brief application of the noninvasive intervention emphasize that the mechanosensitive elements of the musculoskeletal system are not necessarily dependent on strenuous, long-term activity to initiate a structurally relevant response in the adolescent musculoskeletal system. If maintained into adulthood, the beneficial structural changes in trabecular bone, cortical bone, and muscle may serve to decrease the incidence of osteoporotic fractures and sarcopenia later in life.