bluuebunny/crossref_metadata_2025 huggingface dataset:
Low‐frequency variability in the Gulf of Alaska from coarse and eddy‐permitting ocean models
Authors: Capotondi Antonietta , Combes Vincent , Alexander Michael A. , Di Lorenzo Emanuele , Miller Arthur J.
Published: January 2009

An eddy‐permitting ocean model of the northeast Pacific is used to examine the ocean adjustment to changing wind forcing in the Gulf of Alaska (GOA) at interannual‐to‐decadal timescales. It is found that the adjustment of the ocean model in the presence of mesoscale eddies is similar to that obtained with coarse‐resolution models. Local Ekman pumping plays a key role in forcing pycnocline depth variability and, to a lesser degree, sea surface height (SSH) variability in the center of the Alaska gyre and in some areas of the eastern and northern GOA. Westward Rossby wave propagation is evident in the SSH field along some latitudes but is less noticeable in the pycnocline depth field. Differences between SSH and pycnocline depth are also found when considering their relationship with the local forcing and leading modes of climate variability in the northeast Pacific. In the central GOA pycnocline depth variations are more clearly related to changes in the local Ekman pumping than SSH. While SSH is marginally correlated with both Pacific Decadal Oscillation (PDO) and North Pacific Gyre Oscillation (NPGO) indices, the pycnocline depth evolution is primarily related to NPGO variability. The intensity of the mesoscale eddy field increases with increasing circulation strength. The eddy field is generally more energetic after the 1976–1977 climate regime shift, when the gyre circulation intensified. In the western basin, where eddies primarily originate from intrinsic instabilities of the flow, variations in eddy kinetic energy are statistically significant correlated with the PDO index, indicating that eddy statistics may be inferred, to some degree, from the characteristics of the large‐scale flow.
Trapped nitrogen in individual chondrules: Nature of chondrule precursors and clues to formation mechanisms
Authors: Das J. P. , Murty S. V. S.
Published: January 2009

Nitrogen amount and isotopic composition have been measured in individual chondrules of six ordinary chondrites (OC) and two each of carbonaceous (CC) and enstatite chondrites (EC). The [N (ppm), δ15Nt (‰) {corrected for cosmogenic contribution}] for the chondrules have ranges of [0.8 to 61, −97 to +164], [19 to 140, −21 to –31], and [2 to 77, −27 to +116] among OC, EC, and CC, respectively. For OC, while N contents of chondrules fall in the range of bulk OC, δ15N spans a wide range, in contrast to the narrow range (−25 to +14‰) for bulk. For CC chondrules, N contents are lower, while δ15N is different and heavier than bulk. In contrast, EC chondrules and bulk have comparable N and δ15N values. Neither N nor δ15Nt of OC and CC chondrules show any size (expected for nebular exchange) or chemical/mineralogical dependence, ruling out the dominance of secondary effects of nebular or parent body origin. The range of δ15Nt among OC and CC chondrules represents δ15Nt heterogeneity of chondrule precursors and their survival after a high‐temperature chondrule‐forming event. On the basis of δ15N of the chondrules, we propose the presence of at least three N components carried by phase Q, presolar diamonds (HL), and insoluble organic matter (IOM). The precursors of chondrules from OC and CC are different than the bulk OC and CC, which represents the different environment for their formation, compared to the bulk OC and CC. However, for EC chondrules, precursors as well as the formation environment are the same as those of enstatite chondrites.
One‐year Weight Losses in the Look AHEAD Study: Factors Associated With Success
Authors: Wadden Thomas A. , West Delia S. , Neiberg Rebecca H. , Wing Rena R. , Ryan Donna H. , Johnson Karen C. , Foreyt John P. , Hill James O. , Trence Dace L. , Vitolins Mara Z. ,   Look AHEAD Research Group
Published: January 2009

This report provides a further analysis of the first year weight losses in the Look AHEAD (Action for Health in Diabetes) study and identifies factors associated with success. Participants were a total of 5,145 men and women with type 2 diabetes who were recruited at 16 sites and randomly assigned to an intensive lifestyle intervention (ILI) or a control condition, Diabetes Support and Education (DSE). During year 1, participants in ILI received comprehensive diet and physical activity counseling in a total of 42 group and individual sessions, compared with three educational sessions for DSE participants. As reported previously, at the end of the year, ILI participants lost 8.6% of initial weight, compared to 0.7% for DSE (P < 0.001). Within the ILI group, all racial/ethnic groups achieved clinically significant weight losses (>5.5%), although there were significant differences among groups. For the year, ILI participants attended an average of 35.4 treatment sessions and reported exercising a mean of 136.6 min/week and consuming a total of 360.9 meal replacement products. Greater self‐reported physical activity was the strongest correlate of weight loss, followed by treatment attendance and consumption of meal replacements. The use of orlistat, during the second half of the year, increased weight loss only marginally in those ILI participants who had lost <5% of initial weight during the first 6 months and chose to take the medication thereafter as a toolbox option. The lifestyle intervention was clinically effective in all subsets of an ethnically and demographically diverse population.
Prevention of Weight Gain in Adult Patients With Type 2 Diabetes Treated With Pioglitazone
Authors: Kushner Robert F. , Sujak Melissa
Published: January 2009

Pioglitazone, a thiazolidinedione (TZD) commonly used to treat type 2 diabetes, is associated with weight gain. Our study was designed to examine the effectiveness of three lifestyle‐treatment programs of varying intensity on prevention of pioglitazone‐induced weight gain and to measure the composition of the change in body weight. Thirty‐nine adult overweight and obese subjects with type 2 diabetes mellitus were all treated with pioglitazone and prospectively randomized to one of three lifestyle‐treatment programs with increasing level of intensity for 24 weeks. Body composition was measured by dual‐energy X‐ray absorptiometry (DXA), computed tomography, and multifrequency bioimpedance analysis both before and after therapy. Subjects demonstrated a “dose‐response” effectiveness to three levels of lifestyle intervention to mitigate pioglitazone‐induced weight gain. Mean (s.d.) weight change (kg) for the usual, standard, and intensive lifestyle groups were 4.9 ± 4.9 (P = 0.005), 1.8 ± 3.4 (P = 0.02), and −0.2 ± 4.4 (NS) respectively. Total body fat increased 2.6 ± 3.4 kg (P = 0.04) for the usual group and decreased for the intensive group −0.4 ± 3.5 (NS). Change in abdominal subcutaneous and visceral adipose tissue (VAT) did not differ between groups, although ratio of visceral/subcutaneous fat decreased for the standard and intensive groups (NS). Both usual (P < 0.05) and standard care (NS) groups gained total body water. This is the first prospective, randomized study that demonstrates the beneficial effect of participation in a comprehensive lifestyle‐weight‐management program on lessening of weight gain associated with pioglitazone.
Evaluation of Manometric Measures During Tongue-Hold Swallows
Authors: Doeltgen Sebastian H. , Witte Ulrike , Gumbley Freya , Huckabee Maggie-Lee
Published: January 2009

Purpose

Based on visual inspection, prior research documented increased movement of the posterior pharyngeal wall in healthy volunteers during tongue-hold swallows. This manometric study investigated the immediate effects of the tongue-hold maneuver on pharyngeal peak pressure generation, duration of pressure generation, and pressure slope measurements in healthy volunteers.

Method

Pharyngeal pressures from 40 young, healthy individuals (mean age = 25.8 years, gender equally distributed) were recorded at 3 locations: oropharynx, hypopharynx, and upper esophageal sphincter (UES), during normal control and tongue-hold swallows. Measures of peak amplitude, duration, and slope of pressure generation were subjected to statistical analysis.

Results

Tongue-hold swallows produced lower pharyngeal peak pressure and shorter pharyngeal pressure durations compared to control swallows. Further, tongue-hold swallows produced lower UES relaxation pressures. Between sensors, peak pressure was lower and pressure slopes were steeper in the hypopharynx compared to the oropharynx. Several gender-specific differences were found for pharyngeal peak pressure, pressure duration, and pressure slopes.

Conclusions

Reduced amplitude and duration of pharyngeal peak pressure is likely a result of decreased base of tongue retraction during tongue-hold swallows. Central clinical considerations and future research directions are discussed in this article.
The Effect of Aided Language Stimulation on Vocabulary Acquisition in Children With Little or No Functional Speech
Authors: Dada Shakila , Alant Erna
Published: January 2009

Purpose

To describe the nature and frequency of the aided language stimulation program and determine the effects of a 3-week-long aided language stimulation program on the vocabulary acquisition skills of children with little or no functional speech (LNFS).

Method

Four children participated in this single-subject, multiple-probe study across activities. The aided language stimulation program comprised 3 activities: arts and crafts, food preparation, and story time activity. Each activity was repeated over the duration of 5 subsequent sessions. Eight target vocabulary items were taught within each activity. The acquisition of all 24 target items was probed throughout the duration of the 3-week intervention period.

Results

The frequency and nature of the aided language stimulation provided met the criterion of being used 70% of the time and providing aided language stimulation with an 80:20 ratio of statements to questions. The results indicated that all 4 participants acquired the target vocabulary items. There were, however, variations in the rate of acquisition.

Conclusions

This study explores the impact of aided language stimulation on vocabulary acquisition in children. The most important clinical implication of this study is that a 3-week intervention program in aided language stimulation was sufficient to facilitate the comprehension of at least 24 vocabulary items in 4 children with LNFS.
Defining and Measuring Dysphagia Following Stroke
Authors: Daniels Stephanie K. , Schroeder Mae Fern , DeGeorge Pamela C. , Corey David M. , Foundas Anne L. , Rosenbek John C.
Published: January 2009

Purpose

To continue the development of a quantified, standard method to differentiate individuals with stroke and dysphagia from individuals without dysphagia.

Method

Videofluoroscopic swallowing studies (VFSS) were completed on a group of participants with acute stroke (
n
= 42) and healthy age-matched individuals (
n
= 25). Calibrated liquid volumes of 3, 5, 10, and 20 ml were administered during the VFSS. Six measures in 3 domains of bolus flow (timing, direction, and clearance) were measured. Values of these measures obtained from the control group were used to classify dysphagia within the participants.

Results

The use of a single measure or single liquid volumes to classify dysphagia did not distinguish between healthy adults and individuals following stroke with and without dysphagia. Abnormality on more than 1 measure across multiple volumes appears to be a more robust method in defining dysphagia for liquids.

Conclusions

Our findings indicate that the definition of dysphagia is critical in determining whether persons are classified with disordered swallowing. The definition is dependent on materials and measures evaluated. Each measure provides independent aspects to the evaluation. Determining the level of importance of each depends on the purpose of the evaluation.
Broadening the “Ports of Entry” for Speech-Language Pathologists: A Relational and Reflective Model for Clinical Supervision
Authors: Geller Elaine , Foley Gilbert M.
Published: January 2009

Purpose

To offer a framework for clinical supervision in speech-language pathology that embeds a mental health perspective within the study of communication sciences and disorders.

Method

Key mental health constructs are examined as to how they are applied in traditional versus relational and reflective supervision models. Comparisons between traditional and relational and reflective approaches are outlined, with reference to each mental health construct and the developmental level of the supervisee. Three stages of supervisee development are proposed based on research from various disciplines, including nursing, psychology, speech-language pathology, social work, and education. Each developmental stage is characterized by shifts or changes in the supervisee’s underlying assumptions, beliefs, and patterns of behavior.

Conclusion

This article makes the case that both the cognitive and affective dimensions of the supervisor–supervisee relationship need to be addressed without minimizing the necessary development of discipline-specific expertise. The developmental stages outlined in this paradigm can be used to understand supervisees' patterns of change and growth over time, as well as to create optimal learning environments that match their developmental level and knowledge base.
Comprehension of Expository Text: Insights Gained From Think-Aloud Data
Authors: Laing Gillam Sandra , Fargo Jamison D. , St. Clair Robertson Kelli
Published: January 2009

Purpose

To examine the kinds of explicit and implicit statements generated by school-age children with and without language impairments during comprehension of expository texts and to determine the relationship of these statements to comprehension performance.

Method

Forty 4th-grade children with and without language impairments participated in individual think-aloud sessions (verbalizing thoughts aloud). During the sessions, children were asked to listen to expository passages 1 sentence at a time, make comments after each sentence, and then answer questions and recall the passages. The comments or verbal protocols that children generated during the think-aloud sessions were transcribed and analyzed. The relationship of verbal protocols to comprehension performance was evaluated.

Results

Findings suggested that the ability to paraphrase passages was closely related to measures of expository text comprehension.

Conclusions

The use of data obtained during think-aloud sessions may be useful to supplement information gained from traditional measures of comprehension for children with and without language impairments.
Conservation implications of distinct genetic structuring in the endangered freshwater fish Nannoperca oxleyana (Percichthyidae)
Authors: Knight James T. , Nock Catherine J. , Elphinstone Martin S. , Baverstock Peter R.
Published: January 2009

The maintenance of genetic diversity and gene flow in threatened species is a vital consideration for recovery programs. The endangered Oxleyan pygmy perch Nannoperca oxleyana has a fragmented distribution within coastal freshwater drainages of southern Queensland and northern New South Wales, Australia. In the present study, mitochondrial DNA control region variation was used to assess genetic diversity and structure across the geographical range of this species. Haplotypic diversity was highest in a small NSW subcatchment south of Evans Head (h = 0.594) followed by Marcus Creek in Queensland (h = 0.475). Distinct genetic differentiation was evident among the Queensland localities and the NSW subcatchments, implying restricted gene flow between coastal river systems. One of the nine haplotypes detected was distributed over 83.4% of the species’ range, suggesting historical connectivity among the now fragmented populations. These patterns were concordant with eustatic changes associated with the last glacial maximum. High barrier sand dunes may also act as barriers to gene flow and dispersal between adjacent NSW subcatchments. Conservation efforts should focus on the preservation of genetic diversity by maintaining as many genetically differentiated populations as possible. The relatively diverse populations inhabiting the South Evans Head subcatchment and Marcus Creek require special management consideration.
Optimising sample volume and replicates using the Bou-Rouch method for the rapid assessment of hyporheic fauna
Authors: Kibichii Samuel , Baars Jan-Robert , Kelly-Quinn Mary
Published: January 2009

Despite the widespread use of the Bou-Rouch method in obtaining hyporheic samples in ecological studies, problems persist in comparing data because of differences in volume and number of samples taken in various studies. Towards standardising this method, we conducted a study in the Delour River, Ireland, between March and September 2006. The hyporheic habitat was divided into three lateral zones: the flowing stream (SS); the stream–terrestrial ecotone (EC); and the terrestrial margin (TM). Between 3 and 6 random insertions of the stand pipe were made into the hyporheic habitat at 0.2 m and 0.5 m in each zone. Ten consecutive 1-L samples were pumped at each point to determine an optimum sample volume and replicates needed to estimate taxon richness and abundance. The optimum sample combinations range between 6 and 15 3- to 10-L samples depending on depth and habitat zone. Our results show that both spatial and temporal scales are important factors in considering the optimum combinations of sample volume and number of independent spatial replicates needed to sample stream hyporheos, with the zone closer to the flowing stream requiring many small-volume samples whereas areas further away towards the alluvial groundwater need larger volumes with small numbers of replicates.
Polymorphisms in CD1d affect antigen presentation and the activation of CD1d-restricted T cells
Authors: Zimmer Michael I. , Nguyen Hanh P. , Wang Bin , Xu Honglin , Colmone Angela , Felio Kyrie , Choi Hak-Jong , Zhou Ping , Alegre Maria-Luisa , Wang Chyung-Ru
Published: January 2009

CD1 proteins constitute a distinct lineage of antigen-presenting molecules specialized for the presentation of lipid antigens to T cells. In contrast to the extensive sequence polymorphism characteristic of classical MHC molecules, CD1 proteins exhibit limited sequence diversity. Here, we describe the identification and characterization of CD1d alleles in wild-derived mouse strains. We demonstrate that polymorphisms in CD1d affect the presentation of endogenous and exogenous ligands to CD1d-restricted T cells, including type I (Vα14i) and type II (non-Vα14i) natural killer T (NKT) cells. Using congenic mice, we found CD1d polymorphisms affect the thymic selection of type I NKT cells and induce allogeneic T cell responses. Collectively, results from these studies demonstrate a role for polymorphisms in influencing the development and function of CD1d-restricted T cells.
Science for managing ecosystem services: Beyond the Millennium Ecosystem Assessment
Authors: Carpenter Stephen R. , Mooney Harold A. , Agard John , Capistrano Doris , DeFries Ruth S. , Díaz Sandra , Dietz Thomas , Duraiappah Anantha K. , Oteng-Yeboah Alfred , Pereira Henrique Miguel , Perrings Charles , Reid Walter V. , Sarukhan José , Scholes Robert J. , Whyte Anne
Published: January 2009

The Millennium Ecosystem Assessment (MA) introduced a new framework for analyzing social–ecological systems that has had wide influence in the policy and scientific communities. Studies after the MA are taking up new challenges in the basic science needed to assess, project, and manage flows of ecosystem services and effects on human well-being. Yet, our ability to draw general conclusions remains limited by focus on discipline-bound sectors of the full social–ecological system. At the same time, some polices and practices intended to improve ecosystem services and human well-being are based on untested assumptions and sparse information. The people who are affected and those who provide resources are increasingly asking for evidence that interventions improve ecosystem services and human well-being. New research is needed that considers the full ensemble of processes and feedbacks, for a range of biophysical and social systems, to better understand and manage the dynamics of the relationship between humans and the ecosystems on which they rely. Such research will expand the capacity to address fundamental questions about complex social–ecological systems while evaluating assumptions of policies and practices intended to advance human well-being through improved ecosystem services.
Stem cell fate dictated solely by altered nanotube dimension
Authors: Oh Seunghan , Brammer Karla S. , Li Y. S. Julie , Teng Dayu , Engler Adam J. , Chien Shu , Jin Sungho
Published: January 2009

Two important goals in stem cell research are to control the cell proliferation without differentiation and to direct the differentiation into a specific cell lineage when desired. Here, we demonstrate such paths by controlling only the nanotopography of culture substrates. Altering the dimensions of nanotubular-shaped titanium oxide surface structures independently allowed either augmented human mesenchymal stem cell (hMSC) adhesion or a specific differentiation of hMSCs into osteoblasts by using only the geometric cues, absent of osteogenic inducing media. hMSC behavior in response to defined nanotube sizes revealed a very dramatic change in hMSC behavior in a relatively narrow range of nanotube dimensions. Small (≈30-nm diameter) nanotubes promoted adhesion without noticeable differentiation, whereas larger (≈70- to 100-nm diameter) nanotubes elicited a dramatic stem cell elongation (≈10-fold increased), which induced cytoskeletal stress and selective differentiation into osteoblast-like cells, offering a promising nanotechnology-based route for uniqueorthopedics-related hMSC treatments.
Who Cares for Involuntary Clients?
Authors: Soliman Soheil , Pollack Harold A. , Alexander Jeffrey A.
Published: January 2009

The objectives of this study were to compare characteristics of outpatient substance abuse treatment (OSAT) units that serve high proportions of involuntary clients (ICs) with those that serve a low percentage of such clients. The authors analyze unit-level 1995–2005 data from the National Drug Abuse Treatment System Survey (NDATSS). Approximately 1/6 of OSAT units draw the dominant majority of their clients from involuntary referrals. OSAT units that treat a high proportion of ICs are less likely to be accredited by professional organizations, have fewer treatment staff with advanced degrees, and have shorter average treatment duration than do OSAT units that serve few ICs. OSAT units that serve ICs are more likely to offer legal and domestic violence services but are less likely to offer mental health services or aftercare. OSAT units that serve ICs are less likely to be hospital-affiliated than are other units. Clients at such facilities are more likely to be convicted of driving while intoxicated (DWI), are younger, are less likely to have received prior treatment, are more likely to remain abstinent after treatment, but are more likely to be remanded back to courts. The authors conclude that ICs are an important market niche in OSAT care. DWI is by far the most common offense reported in units that specialize in ICs. Aside from legal and domestic violence services, units with a high proportion of ICs appear to offer somewhat less intensive and professionalized services than do other facilities; however, clients at these units are more likely to be abstinent at the end of treatment and but more likely to be remanded back to the courts.
Psychometric Properties of a Brief Smoking Consequences Questionnaire for Adults (SCQ-A) among African American Light Smokers
Authors: Thomas Janet L. , Bronars Carrie A. , Stewart Diana W. , Okuyemi Kolawole S. , Befort Christie A. , Nazir Niaman , Mayo Matthew S. , Jeffries Shawn K. , Ahluwalia Jasjit S.
Published: January 2009

Despite a decline in cigarette smoking over the past few decades, rates remain unacceptably high for certain segments of the population, such as urban African Americans (AAs). AA smokers, on average, smoke fewer cigarettes per day than European American samples; however, AA smokers are less likely to achieve abstinence during a quit attempt. Outcome expectancies have previously been association with cessation outcomes, but prior research has not examined expectancies among treatment-seeking AA light smokers. The 33-item Smoking Consequences Questionnaire–Adult (SCQ-A) was evaluated among 751 AA light smokers (i.e., ≤ 10 cigarettes per day) enrolled in a cessation trial. Exploratory factor analyses replicated the original 10-factor solution. Factors were significantly correlated ( r = −.06–51, P < .001) and associated with expected demographic, psychosocial, and tobacco-related variables. Results provide initial validation of the SCQ-A among AA light smokers seeking cessation treatment and highlight the association of smoking expectancies with other tobacco-related and psychosocial factors in this sample.
Psychosocial and Health Aspects of Drug Use by Students in Public Secondary Schools in Nairobi, Kenya
Authors: Ndetei David M. , Khasakhala Lincoln I. , Mutiso Victoria , Ongecha-Owuor Francisca A. , Kokonya Donald A.
Published: January 2009

The objective of this study was to evaluate the influence of family, psychosocial, health, demographic, and behavioral characteristics on regular drug use. All the students of 17 randomly stratified public secondary schools in Nairobi were required to complete self-administered sociodemographic and the Drug Use Screening Inventory–Revised (DUSI-R) questionnaires in a cross-sectional descriptive study. All the 1328 students, of whom 58.9% were male, responded to all the questions, giving a response rate of 100%. The mean age of the respondents was 16 years and 78.1% were in boarding school. One third (33.9%) scored positively for substance abuse. Significant correlations were found between several domains of substance abuse and school, class, mode of school attendance, age, and gender. Students abusing drugs have multiple comorbidity of medical, psychological, and social pathologies. There are evidence-based intervention entry points for drug abuse that go beyond mere impartation on knowledge about the harmful effects of drugs.
Patterns of Drug Abuse in Public Secondary Schools in Kenya
Authors: Ndetei David M. , Khasakhala Lincoln I. , Mutiso Victoria , Ongecha-Owuor Francisca A. , Kokonya Donald A.
Published: January 2009

The objective of this study was to establish the association between substance abuse and the sociodemographic characteristics of secondary school students. All the students of 17 randomly stratified public secondary schools in Nairobi were required to complete self-administered sociodemographic and the School Toolkit questionnaires in a cross-sectional descriptive survey. Nearly all (96.6%; 1252/1296) the students, comprising more males (62.5%) than females, completed all the items on the questionnaires. Their mean age was 17 years. Alcohol and cigarette use were common and began as early as before age 11. No significant correlation was found between fathers’ education and substance abuse. Mothers’ education had a significant but negative correlation. There were increased rates of substance abuse compared to past surveys. Campaigns against drug use should include those aged 11 years and should focus on education on the dangers of alcohol and tobacco use, as these are gateways to use of other drugs.
A Novel CBT Web Course for the Substance Abuse Workforce: Community Counselors’ Perceptions
Authors: Larson Mary Jo , Amodeo Maryann , Storti Susan A. , Steketee Gail , Blitzman Geri , Smith Lauren
Published: January 2009

This article describes (a) a Web-based course for substance abuse counselors on cognitive behavioral therapy (CBT), and (b) the evaluation of a prototype module from the Web-based course to determine the feasibility of the e-learning program for a community-based counselor audience. The course is part of a unique study that trains counselor-supervisor teams to increase the transfer of learned skills to the agency. Following curriculum design, the authors sought counselor reactions to the prototype module on strengths/limitations of the design, functionality, and effectiveness. Results showed that counselors learned new information, found this format effective compared to other training, and wanted to complete a full CBT Web course. Counselors’ evaluation led to content and technology changes: the authors added and segmented material aimed at the advanced, more theoretically oriented counselor, and housed these topics behind an “advanced concept” graphics button; added seven screens to accommodate text broken into smaller units; and increased the difficulty of the end-of-module quiz.
UltraScience Net: High-Performance Network Research Test-Bed
Authors: Rao Nageswara S. V. , Wing William R. , Hicks Susan E. , Poole Stephen W. , Denap Frank A. , Carter Steven M. , Wu Qishi
Published: January 2009

The high-performance networking requirements for next generation large-scale applications belong to two broad classes: a) high bandwidths, typically multiples of 10Gbps, to support bulk data transfers, and b) stable bandwidths, typically at much lower bandwidths, to support computational steering, remote visualization, and remote control of instrumentation.

Current Internet technologies, however, are severely limited in meeting these demands because such bulk bandwidths are available only in the backbone, and stable control channels are hard to realize over shared connections. The UltraScience Net (USN) facilitates the development of such technologies by providing dynamic, cross-country dedicated 10Gbps channels for large data transfers, and 150 Mbps channels for interactive and control operations. Contributions of the USN project are two-fold: Infrastructure Technologies for Network Experimental Facility: USN developed and/or demonstrated a number of infrastructure technologies needed for a national-scale network experimental facility. Compared to Internet, USN's data-plane is different in that it can be partitioned into isolated layer-1 or layer-2 connections, and its control-plane is different in the ability of users and applications to setup and tear down channels as needed. Its design required several new components including a Virtual Private Network infrastructure, a bandwidth and channel scheduler, and a dynamic signaling daemon. The control-plane employs a centralized scheduler to compute the channel allocations and a signaling daemon to generate configuration signals to switches. In a nutshell, USN demonstrated the ability to build and operate a stable national-scale switched network. Structured Network Research Experiments: A number of network research experiments have been conducted on USN that cannot be easily supported over existing network facilities, including test-beds and production networks. It settled an open matter by demonstrating that the performance of switched connections and Multiple Protocol Label Switching tunnels over routed networks are comparable. Furthermore, such connections can be easily peered, and the performance of the resultant hybrid connections is still comparable to the constituent pure connections. USN experiments demonstrated that Infiniband transport can be effectively extended to wide-area connections of thousands of miles, which opens up new opportunities for efficient bulk data transport. USN provided dedicated connections to Cray X1 supercomputer and helped diagnose TCP performance problems which might have been otherwise incorrectly attributed to traffic on shared connections. USN contributed to the development of transport methods for dedicated connections to other traffic. Recently, experiments were conducted to assess the performance of application acceleration devices that employ flow optimization and data compression methods to improve TCP performance.
A Mobile-Based Face Verification System
Authors: Ou Zongying , Su Tieming , Ou Fan , Zhang Jianxin , Liu Dianting
Published: January 2009

Intelligent mobile phones equipped with a camera are very popular in our daily lives now. Face verification running on mobile phone provides not only a tool for the protection of the owner's authority but also an approach for verification from a distance. The combination of biometrics and telecommunication technologies possesses broad application potentials in information exchanges. However, there are also some critical issues needing solving. Usually the processing power and memory size of a mobile phone system are limited, and the acquisition images are suffered from the illumination changes.

An acquisition image I(x,y) can be modeled as a product of the reflectance R and Illuminant effect L shown as I(x,y) = R(x,y)∗L(x,y). The reflectance attribution R(x,y) is the inherent feature of a human face for verification. Compared with the reflectance changes rapidly across the contour of a face, usually the illumination changes smoothly and slowly. If two pixels are located nearby, the ratio of the reflectance between these two pixels can be calculated via the ratio of their illuminations, which is approximately independent from illumination changes. Based on this invariant property of the ratio of illumination at a pixel to its surrounding neighbor illuminations, an illumination normalization technique was developed and adapted to the mobile system.

A dedicated scheme composed of special wavelets called Gab features was proposed for representation of human faces. Gabor features reveal more structure information of images; however, the data dimensionality is becoming very high. An optimization processing was designed for searching the optimal Gabor node configuration and reducing the number of Gabor nodes effectively.

To fit the limitation of the phone processor, all the floating point calculations were implemented with integer calculations, the feature extraction and discriminating verification algorithms were carefully designed to accelerate implementation and control the heap and stack sizes. A mobile based face verification system was developed and embedded in the Lenovo ET980 mobile phone, which is equipped with CPU Intel XScale PX270, memory 128MB Flash/64 MB SDRAM, and a 4 million pixel camera. The experiments testing on FERET fafb dataset show that the system Equal False Accept Rate and False Reject Rate achieved 1.51%; and the False Accept Rates achieved 2.12% and 6.81%, while the False Reject Rate at 1% and 0.1% respectively. The processing time is about 1 second. The performance of this system is quite well.
Automatic Verification for Secrecy of Cryptographic Protocols in First-Order Logic
Authors: Han Jihong , Zhou Zhiyong , Wang Yadi
Published: January 2009

In this article, we present a new formal approach for specification and automatic verification of cryptographic protocols. First, we use the first-order theory to formalize cryptographic protocols and intruders. Assuming that messages transmitted by each principal can be received by the intruder, and messages received by each principal can be known by the intruder, we test the security of cryptographic protocols at the standpoint of the intruder. The protocol representation includes three parts: initial knowledge of the intruder, message exchange of the protocol itself, and computation abilities of the intruder. After defining the term and its typeset, we give a first-order frame to formalizing the protocol based on roles, using axioms to depict the communicating actions of each role. The predicate corresponding to the role's message receiving can be affiliated to the axiom by logical connective ^, and the predicate corresponding to the role's message transmitting can be the conclusion of the implication relation. The universal quantification ∀ is used to eliminate the limitation for protocol runs, and existential quantification ∃ is used to denote generating of the key or the nonce, and through renaming and consistency check, ensure the refreshness and boundlessness of the new value. In order to implement the automatic verification, we propose a normal approach to transform the axioms into Horn clauses. Following the Dolev-Yao Model, the computation abilities of the intruder are modeled in Horn clauses too. We adopt the deductive reasoning method to verify the secrecy property of cryptographic protocols. The secrecy property is considered as a goal, and based on a deductive algorithm we can check whether the goal can be inferred from the known rules. The known rules form a rule base B containing the Horn clauses of protocol description and the intruder's abilities and initial knowledge. If the goal can be inferred from the base, the sequence of rules applied will lead to the description of an attack scenario. This approach is fully automatic and terminable. The main contributions of the paper are: a general framework of formalizing cryptographic protocol and abilities of the intruder, a practical solving algorithm based on automatic reasoning, and a simple method to find the attack scenarios.
An Efficient Framework for Configurable Video Encoder
Authors: Li Wei , Zhou Bing
Published: January 2009

The implementation of real-time video coding systems with limited resources such as memory volume and CPU speed is a challenging task. In this paper, an efficient embedded multi-modal MPEG-4 video encoder (EMVC) is proposed and implemented to meet the requirement of encoding different modals (colors, resolutions, and bandwidths) video in size and power-restricted scenario.

The hardware framework of EMVC is based on FPGA and DSP, which takes full advantage of the strongpoint of DSP and FPGA—powerful digital signal processing ability of DSP is utilized to complete most of the complex video coding, and flexible configuration, the parallelism and high speed of FPGA cooperates to accomplish logical control and auxiliary functions in video coding. The hardware framework is designed with strong processing ability, flexible configuration, and extensive coverage.

In software design, we first improve some key algorithms in MPEG-4 standard that have great impact on coding efficiency, a fast motion estimation algorithm—smooth motion vector field adaptive search technique (SMVFAST) and a DSP-based efficient quantization computation method—EQ4DSP are put forward respectively; second, according to the characters of DSP's hardware resource, the encoder software is optimized at system and code levels. At the system level, EDMA (Enhanced Direct Memory Access) channels in DSP are used to parallel the data transfer, and the software structure of the video encoders is changed from frame-based to GMB-based (Group of Macro-Block) to make use of the parallel processing capacity of DSP. At code level, the codes of the frequently called modules in the encoder are the critical optimized part, and the main code optimization methods used in EMVC include: using an intrinsic function to replace the complicated C/C++ code, using packed data processing to maximize the data throughput, unrolling the loop to increase software pipelines, translating C code to Linear Assembly, and so on.

By making use of the reserved user-data field in the MPEG-4 standard syntax, a multi-modal function of EMVC is realized, namely, the system can switch among 720 × 576 and 352 × 288 resolutions, grey and color video, 2 M and 256 K bandwidth. Moreover, the mode switch can be achieved in real time according to the input control command.

Experimental results show that EMVC not only runs efficiently but also has good flexibility and generality. Furthermore, by realizing diverse video or image coding algorithms, it can also satisfy the requirements of various embedded video applications, especially those with strict restriction in size, power consumption, and control flexibility.
Trust Architecture in Dynamic Systems
Authors: Yajun Guo , Zhongqiang Yu , Hao Chen , Huihui Dong
Published: January 2009

Trust is the key for an information system to make security decisions. There does not exist in an aforehand trust relationship among principals in dynamic systems. To secure transaction, trust relationship must be established in principals. However, the existing trust architectures are flat, so they cannot embody well the dynamic characteristic of trust and do not take on well operability. In this paper, a two-layer trust architecture for dynamic systems is presented. Trust in this model is composed of a basic trust layer and a dynamic trust layer. Basic trust depends on the attributes of a principal, recommendation, or experience, while dynamic trust relies on the application context. This trust structure can reduce the complexity of making a decision in dynamic system.

In dynamic systems, there are many factors to form trust, such as principal experience, attribute, recommendation, and context. In these trust factors, the context trust factor is different from the others, which it changes when close with the current context. We classify these trust factors into two groups. The first group includes experience, attribute, and recommendation to form this basic trust, while the second group involves current context to form dynamic trust. The trust value in this two-layer trust architecture was expressed as T = (Ta, Tc). Where Ta is the combination trust value of the attribute trust, experience, and recommendation trust, and Tc is the context trust value. Obviously, the relationship among trust values is a partial ordering.

Experience usually associates with events. Positive trust events can increase the experience value, and negative trust events will reduce the experience. Because the importance of events is different, each event is assigned a weight. The larger the weight is, the more important the event is. Experience evaluation strategy provides the evaluation method for the occurred event.

The attribute trust is the evaluation of the credibility, reliability, and security ability of the trusted principal according to the attributes of the trusted principal.

The context trust is the trust evaluation of principals in a special context. Trust strategy is different in the different application context. For example, the trust strategy of a printer may be “medium” when the printer is free and the principal is in the offices, and may be “low” when the principal is not in the office, or when the printer is busy. The context trust value is the function of the context information: Tc = h(C), C is the context information.
Intrusion Prevention in Depth System Research Based on Data Mining
Authors: Jie Wang , Xiao Zheng , Yabin Liu , Chenghui Shi
Published: January 2009

This article proposes a data mining based intrusion prevention in depth system model to manage the huge amounts of unreliable and uncontrollable security events, which are generated by the extensive utilization of heterogeneous security devices in computer networks. A method of combining online detection and offline data mining is made use of as the core of the model. On the other hand, the work process of the system can be compartmentalized into two phases: online examination through pattern matching and offline training through data mining. By the online real-time data examination, the data are captured through the protocol analyzer at first, and then passed through the processor of regular rule set and parameters based detection engine. After corresponding processing to the data, the system can decide if the data should be stored and forwarded or an alarm management operation should be stimulated. By the offline data mining, the data preprocess module pretreats the data from various kinds of invasion and appraisal, and combines the mined knowledge to data that come from the compound detection engine and the policy making engine. The regular rule set is then updated and optimized through the new knowledge acquired by the offline data mining phase. The phases of online examination and offline data mining are executed alternatively and/or synchronously according to requirements of achieving optimal performance of the system. In our UPNSM, we unify the rule and the policy together to form the policy by the classified rule set and the human-computer interface and distribute policy to examination engines. This method provides our platform a better assistance to carry on various kinds of nimble effective operation. In fact, the model is a united network security management platform used to analyze the network and host data from different layers: the kernel layer, the concentration layer, and the access layer. Through enhancing the capture speed of the network data package, the proposed model can evidently improve the efficiency of traditional IPS for detection network intrusion. This verity can be demonstrated by simulation and experiment results. Thus, the proposed intrusion prevention in depth system model can be used for defense in real-time and defense in depth.
A Detector Generating Algorithm Based on Interval Partition
Authors: Xia Huifen , Ju Shiguang , Cai Tao
Published: January 2009

Based on the functions and some relevant theories of the biological immune system, an artificial immune system is established to solve the practical problems for computing systems. At present, the artificial immune system includes two major categories: the mechanism of non-self recognition and immune network, the most important of which is negative selection algorithm. The negative selection algorithm is proposed to simulate the formation and running mechanism of T cells for the immune system in 1994. In this algorithm, one of the key steps is the detector generation. Unfortunately, the current detector generating algorithms have detector generation inefficiencies, holes area, and redundant detector problems to some degree. In this paper, from the perspective of one dimension, a novel detector generating algorithm that is based on interval partition is proposed. At the beginning of this algorithm, we make the maximal interval be the initial detector; second, this detector should experience the training of self-tolerance. According to the matching rule, we let this detector match the given collection of selves; then we remove the points from the interval detector which matches the selves. At the same time, we divide the interval into two parts at this point and have the candidate detectors optimized by the corresponding interval collations and amalgamations. That is to say, the initial detector interval is divided recursively according to the spatial locations of selves. At last, we can get a set of excellent mature detectors, which can be used to protect the system security. To illustrate the advantage of this algorithm, we have given an example. From this example, we can declare that the algorithm improves the current detector generations and matching rules greatly. It also helps to remove the holes area and redundant detectors. Therefore, both the detector generation efficiency and the detecting efficiency are well improved. By the theoretical analysis and comparison, the system can detect a large number of non-self antigens only using a small quantity of detectors. Obviously, the algorithm achieves the high non-self identification system.