bluuebunny/crossref_metadata_2025 huggingface dataset:
A hierarchical evolutionary algorithm for multiobjective optimization in IMRT
Authors: Holdsworth Clay , Kim Minsun , Liao Jay , Phillips Mark H.
Published: August 2010

Purpose:

The current inverse planning methods for intensity modulated radiation therapy (IMRT) are limited because they are not designed to explore the trade‐offs between the competing objectives of tumor and normal tissues. The goal was to develop an efficient multiobjective optimization algorithm that was flexible enough to handle any form of objective function and that resulted in a set of Pareto optimal plans.

Methods:

A hierarchical evolutionary multiobjective algorithm designed to quickly generate a small diverse Pareto optimal set of IMRT plans that meet all clinical constraints and reflect the optimal trade‐offs in any radiation therapy plan was developed. The top level of the hierarchical algorithm is a multiobjective evolutionary algorithm (MOEA). The genes of the individuals generated in the MOEA are the parameters that define the penalty function minimized during an accelerated deterministic IMRT optimization that represents the bottom level of the hierarchy. The MOEA incorporates clinical criteria to restrict the search space through protocol objectives and then uses Pareto optimality among the fitness objectives to select individuals. The population size is not fixed, but a specialized niche effect, domination advantage, is used to control the population and plan diversity. The number of fitness objectives is kept to a minimum for greater selective pressure, but the number of genes is expanded for flexibility that allows a better approximation of the Pareto front.

Results:

The MOEA improvements were evaluated for two example prostate cases with one target and two organs at risk (OARs). The population of plans generated by the modified MOEA was closer to the Pareto front than populations of plans generated using a standard genetic algorithm package. Statistical significance of the method was established by compiling the results of 25 multiobjective optimizations using each method. From these sets of 12–15 plans, any random plan selected from a MOEA population had a chance of dominating any random plan selected by a standard genetic package with chance of domination in reverse. By implementing domination advantage and protocol objectives, small and diverse populations of clinically acceptable plans that approximated the Pareto front could be generated in a fraction of 1 h. Acceleration techniques implemented on both levels of the hierarchical algorithm resulted in short, practical runtimes for multiobjective optimizations.

Conclusions:

The MOEA produces a diverse Pareto optimal set of plans that meet all dosimetric protocol criteria in a feasible amount of time. The final goal is to improve practical aspects of the algorithm and integrate it with a decision analysis tool or human interface for selection of the IMRT plan with the best possible balance of successful treatment of the target with low OAR dose and low risk of complication for any specific patient situation.
Dosimetric impact of an brachytherapy source cable length modeled using a grid‐based Boltzmann transport equation solver
Authors: Mikell Justin K. , Mourtada Firas
Published: August 2010

Purpose:

To evaluate the dose distributions of an source (model VS2000) in homogeneous water geometry calculated using a deterministic grid‐based Boltzmann transport equation solver (GBBS) in the commercial treatment planning system (TPS) (BRACHYVISION‐ACUROS v8.8).

Methods:

Using percent dose differences, the GBBS (BV‐ACUROS) was compared to the (1) published TG‐43 data, (2) MCNPX Monte Carlo (MC) simulations of the source centered in a 15 cm radius water sphere, and (3) TG‐43 output from the TPS using vendor supplied (BV‐TG43‐vendor) and user extended (BV‐TG43‐extended) 2D anisotropy functions . BV‐ACUROS assumes 1 mm of NiTi cable, while the TPS TG‐43 algorithm uses data based on a 15 cm cable. MC models of various cable lengths were simulated.

Results:

The MC simulations resulted in dose deviations along the cable for 1, 2, and 3 mm cable lengths relative to 15 cm. BV‐ACUROS comparisons with BV‐TG43‐vendor and BV‐TG43‐extended yielded magnitude of differences, consistent with those seen in MC simulations. However, differences extended further when using the vendor supplied anisotropy function . These differences were also seen in comparisons of derived from the TPS output.

Conclusions:

The results suggest that near the cable region is larger than previously estimated. The spatial distribution of the dose deviation is highly dependent on the reference TG‐43 data used to compare to GBBS. The differences observed, while important to realize, should not have an impact on clinical dosimetry in homogeneous water.
Comparison of three strategies in management of independent movement of the prostate and pelvic lymph nodes
Authors: Xia Ping , Qi Peng , Hwang Andrew , Kinsey Erica , Pouliot Jean , Roach Mack
Published: August 2010

Purpose:

Concurrent irradiation of the prostate and pelvic lymph nodes is technically challenging due to treating one moving target and one immobile target. The purposes of this article are to propose a new management strategy and to compare this strategy to the conventional isocenter shift method and the previously proposed MLC‐shifting method.

Methods:

To cope with two target volumes (one moving and one immobile), the authors propose a new management strategy referred to as multiple adaptive plans (MAPs). This strategy involves the creation of a pool of plans for a number of potential prostate locations. Without requiring any additional hardware or software, the MAP strategy is to choose a plan from the pool that most closely matches the “prostate position of the day.” This position can be determined by dual image registrations: One aligned to the implant markers in the prostate and the other aligned to the pelvic bones. This strategy was clinically implemented for a special patient with high risk prostate cancer and pathologically confirmed positive pelvic lymph nodes, requiring concurrent IMRT treatment of the prostate and pelvic lymph nodes. Because this patient had an abdominal kidney, small planning margins around the both targets were desired. Using 17 daily acquired megavoltage cone beam CTs (CBCTs), three sets of validation plans were calculated to retrospectively evaluate the MAP strategy as well as the isoshifting and MLC‐shifting strategies.

Results:

According to the validation plans, MAP, isoshifting, and MLC‐shifting strategies resulted in of the prostate of the daily dose on 65%, 100%, and 100% treatment days, respectively. Similarly, of the pelvic lymph nodal was of the daily dose on 100%, 75%, and 94% of treatment days, respectively.

Conclusions:

None of the above strategies simultaneously achieved all treatment goals. Among the three strategies, the MLC shifting was most successful. Validation plans based on daily CBCTs are useful to evaluate the effectiveness of the motion management strategies and to provide additional dose guidance if further dose compensation is needed.
In vivo imaging and treatment of solid tumor using integrated photoacoustic imaging and high intensity focused ultrasound system
Authors: Cui Huizhong , Yang Xinmai
Published: August 2010

Purpose:

The purpose of this study is to show the feasibility of combined contrast imaging and treatment of solid tumorin vivo by an integrated photoacoustic imaging and high intensity focused ultrasound (HIFU) system.

Methods:

During this study, photoacoustic imaging was performed to identify the location of a CT26 tumor, which was subcutaneously inoculated on the hip of a BALB/c mouse. Then the CT26 tumor was ablated by HIFU with the guidance of photoacoustic images. To enhance the contrast and specificity of photoacoustic imaging, gold nanorods were used as the contrast agents during the experiment. After being injected into the blood stream, gold nanorods passively accumulated around the tumor region, and therefore outlined the location and shape of the tumor in the photoacoustic images, which were used to guide the subsequent HIFU therapy.

Results:

The experiment results showed that the tumor was clearly visible on photoacoustic images after the injection of gold nanorods and HIFU was able to ablate the tumor under the guidance of photoacoustic imaging.

Conclusions:

The authors demonstrated that their integrated photoacoustic imaging and HIFU system has the potential for contrast imaging with gold nanorods with possible diagnosis and treatment of solid tumors.
4D XCAT phantom for multimodality imaging research
Authors: Segars W. P. , Sturgeon G. , Mendonca S. , Grimes Jason , Tsui B. M. W.
Published: August 2010

Purpose

: The authors develop the 4D extended cardiac‐torso (XCAT) phantom for multimodality imaging research.

Methods:

Highly detailed whole‐body anatomies for the adult male and female were defined in the XCAT using nonuniform rational B‐spline (NURBS) and subdivision surfaces based on segmentation of the Visible Male and Female anatomical datasets from the National Library of Medicine as well as patient datasets. Using the flexibility of these surfaces, the Visible Human anatomies were transformed to match body measurements and organ volumes for a 50th percentile (height and weight) male and female. The desired body measurements for the models were obtained using thePEOPLESIZE program that contains anthropometric dimensions categorized from 1st to the 99th percentile for US adults. The desired organ volumes were determined from ICRP Publication 89 [ICRP, “Basic anatomical and physiological data for use in radiological protection: reference values,” ICRP Publication 89 (International Commission on Radiological Protection, New York, NY, 2002)]. The male and female anatomies serve as standard templates upon which anatomical variations may be modeled in the XCAT through user‐defined parameters. Parametrized models for the cardiac and respiratory motions were also incorporated into the XCAT based on high‐resolution cardiac‐ and respiratory‐gated multislice CT data. To demonstrate the usefulness of the phantom, the authors show example simulation studies in PET, SPECT, and CT using publicly available simulation packages.

Results:

As demonstrated in the pilot studies, the 4D XCAT (which includes thousands of anatomical structures) can produce realistic imaging data when combined with accurate models of the imaging process. With the flexibility of the NURBS surface primitives, any number of different anatomies, cardiac or respiratory motions or patterns, and spatial resolutions can be simulated to perform imaging research.

Conclusions:

With the ability to produce realistic, predictive 3D and 4D imaging data from populations of normal and abnormal patients under various imaging parameters, the authors conclude that the XCAT provides an important tool in imaging research to evaluate and improve imaging devices and techniques. In the field of x‐ray CT, the phantom may also provide the necessary foundation with which to optimize clinical CT applications in terms of image quality versus radiation dose, an area of research that is becoming more significant with the growing use of CT.
Assessment of variation in Elekta® plastic spherical‐calibration phantom and its impact on the Leksell Gamma Knife® calibration
Authors: Novotny Josef , Bhatnagar Jagdish P. , Chung Hyun‐Tai , Johansson Jonas , Bednarz Greg , Ma Lijun , Saiful Huq M.
Published: August 2010

Purpose:

Traditionally, the dose‐rate calibration (output) of the Leksell Gamma Knife® (LGK) unit is performed using a 160 mm diameter plastic spherical phantom provided by the vendor of the LGK, Elekta Instrument AB. The purpose of this study was to evaluate variations in the Elekta spherical phantom and to assess its impact and use for the LGK calibration.

Methods:

Altogether, 13 phantoms from six different centers were acquired, 10 of these phantoms were manufactured within the past 10 years and the last 3 approximately 15–20 years ago. To assess variation in phantoms, the diameter and mass densities were measured. To assess the impact on LGK calibration, the output of two models of LGK (LGK Perfexion™ and LGK 4C) were measured under identical irradiation conditions using all 13 phantoms for each LGK model.

Results:

The mean measured deviation in diameter from expected nominal 160 mm for 13 phantoms was 0.51 mm (range of 0.09–1.51 mm). The mean measured phantom mass density for 13 phantoms was (range of ). The percentage deviation of output for individual phantom from mean of 13 phantom outputs ranged from −0.37% to 0.55% for LGK Perfexion™. Similarly, the percentage deviation of output for individual phantom from mean of 13 phantom outputs ranged from −0.72% to 0.47% for LGK 4C.

Conclusions:

This study demonstrated that small variations in terms of phantom size and mass density of the phantom material do not have a significant impact on dose‐rate measurements of the Leksell Gamma Knife®. Also, date of manufacture of the phantom did not show up to be a significant factor in this study.
Assessment of 2D and 3D fractal dimension measurements of trabecular bone from high‐spatial resolution magnetic resonance images at 3 T
Authors: Alberich‐Bayarri Angel , Marti‐Bonmati Luis , Pérez Maria Angeles , Sanz‐Requena Roberto , Lerma‐Garrido Juan José , García‐Martí Gracián , Moratal David
Published: August 2010

Purpose:

In vivo two‐dimensional (2D) fractal dimension analysis of the cancellous bone at 1.5 T has been related to bone structural complexity and shown to be a potential imaging‐based biomarker for osteoporosis. The objectives of this study were to assess at 3 T the in vivo feasibility of three‐dimensional (3D) bone fractal dimension analysis, analyze the relationship of and with osteoporosis, and investigate the relationship of with spinal bone mineral density (BMD).

Methods:

A total of 24 female subjects ( old, ) was included in this study. The cohort consisted of 12 healthy volunteers and 12 patients with osteoporosis. MR image acquisitions were performed in the nondominant metaphysis of the distal radius with a 3 T MR scanner and an isotropic resolution of . After segmentation and structural reconstruction, 2D and 3D box‐counting algorithms were applied to calculate the fractal complexity of the cancellous bone. and values were compared between patients with osteoporosis and healthy subjects, and their relationship with radius BV/TV and spinal BMD was also assessed.

Results:

Significant differences between healthy subjects and patients with osteoporosis were obtained for , with less differentiation for . The relationship between fractal dimension and BMD was not significant (, and , , for and , respectively).

Conclusions:

The feasibility of trabecular bone calculations at 3 T and the relationship of both and parameters with osteoporosis were demonstrated, with a better differentiation for the 3D method. Furthermore, the parameter has probably a different nature of information regarding the trabecular bone status not directly explained by BMD alone. Future studies with subjects with osteopenia and larger sample sizes are warranted to further establish the potential of and in the study of osteoporosis.
Compressed sensing based cone‐beam computed tomography reconstruction with a first‐order methoda)
Authors: Choi Kihwan , Wang Jing , Zhu Lei , Suh Tae‐Suk , Boyd Stephen , Xing Lei
Published: August 2010

Purpose:

This article considers the problem of reconstructing cone‐beam computed tomography (CBCT) images from a set of undersampled and potentially noisy projection measurements.

Methods:

The authors cast the reconstruction as a compressed sensing problem based on norm minimization constrained by statistically weighted least‐squares of CBCT projection data. For accurate modeling, the noise characteristics of the CBCT projection data are used to determine the relative importance of each projection measurement. To solve the compressed sensing problem, the authors employ a method minimizing total‐variation norm, satisfying a prespecified level of measurement consistency using a first‐order method developed by Nesterov.

Results:

The method converges fast to the optimal solution without excessive memory requirement, thanks to the method of iterative forward and back‐projections. The performance of the proposed algorithm is demonstrated through a series of digital and experimental phantom studies. It is found a that high quality CBCT image can be reconstructed from undersampled and potentially noisy projection data by using the proposed method. Both sparse sampling and decreasing x‐ray tube current (i.e., noisy projection data) lead to the reduction of radiation dose in CBCT imaging.

Conclusions:

It is demonstrated that compressed sensing outperforms the traditional algorithm when dealing with sparse, and potentially noisy, CBCT projection views.
Focus Issue: Systems Analysis of Protein Phosphorylation
Authors: Gough Nancy R. , Foley John F.
Published: August 2010

Kinases and phosphatases are stars in the signaling universe.
Targeting the Reversibly Oxidized Protein Tyrosine Phosphatase Superfamily
Authors: Boivin Benoit , Yang Ming , Tonks Nicholas K.
Published: August 2010

Mildly acidic pH and degassed buffers are the keys to successfully identifying redox-sensitive tyrosine phosphatases.
Environmental Study of Azole-Resistant
Aspergillus fumigatus
and Other Aspergilli in Austria, Denmark, and Spain
Authors: Mortensen Klaus Leth , Mellado Emilia , Lass-Flörl Cornelia , Rodriguez-Tudela Juan Luis , Johansen Helle Krogh , Arendrup Maiken Cavling
Published: August 2010

A single mechanism of azole resistance was shown to predominate in clinical and environmental
Aspergillus fumigatus
isolates from the Netherlands, and a link to the use of azoles in the environment was suggested. To explore the prevalence of azole-resistant
A. fumigatus
and other aspergilli in the environment in other European countries, we collected samples from the surroundings of hospitals in Copenhagen, Innsbruck, and Madrid, flowerbeds in an amusement park in Copenhagen, and compost bags purchased in Austria, Denmark, and Spain and screened for azole resistance using multidish agars with itraconazole, voriconazole, and posaconazole. EUCAST method E.DEF 9.1 was used to confirm azole resistance. The promoter and entire coding sequence of the
cyp51A
gene were sequenced to identify azole-resistant
A. fumigatus
isolates.
A. fumigatus
was recovered in 144 out of 185 samples (77.8%). Four
A. fumigatus
isolates from four Danish soil samples displayed elevated azole MICs (8%), and all harbored the same TR/L98H mutation of
cyp51A
. One
A. lentulus
isolate with voriconazole MIC of 4 mg/liter was detected in Spain. No azole-resistant aspergilli were detected in compost. Finally,
A. terreus
was present in seven samples from Austria. Multi-azole-resistant
A. fumigatus
is present in the environment in Denmark. The resistance mechanism is identical to that of environmental isolates in the Netherlands. No link to commercial compost could be detected. In Spain and Austria, only
Aspergillus
species with intrinsic resistance to either azoles or amphotericin B were found.
Mathematical Modeling To Characterize the Inoculum Effect
Authors: Bhagunde Pratik , Chang Kai-Tai , Singh Renu , Singh Vandana , Garey Kevin W. , Nikolaou Michael , Tam Vincent H.
Published: August 2010

Killing by beta-lactams is well known to be reduced against a dense bacterial population, commonly known as the inoculum effect. However, the underlying mechanism of this phenomenon is not well understood. We proposed a semimechanistic mathematical model to account for the reduced
in vitro
killing observed. Time-kill studies were performed with 4 baseline inocula (ranging from approximately 1 × 10
5
to 1 × 10
8
CFU/ml) of
Escherichia coli
ATCC 25922 (MIC, 2 mg/liter). Constant but escalating piperacillin concentrations used ranged from 0.25× to 256× MIC. Serial samples were taken over 24 h to quantify viable bacterial burden, and all the killing profiles were mathematically modeled. The inoculum effect was attributed to a reduction of effective drug concentration available for bacterial killing, which was expressed as a function of the baseline inoculum. Biomasses associated with different inocula were examined using a colorimetric method. Despite identical drug-pathogen combinations, the baseline inoculum had a significant impact on bacterial killing. Our proposed mathematical model was unbiased and reasonable in capturing all 28 killing profiles collectively (
r
2
= 0.88). Biomass was found to be significantly more after 24 h with a baseline inoculum of 1 × 10
8
CFU/ml, compared to one where the initial inoculum was 1 × 10
5
CFU/ml (
P
= 0.002). Our results corroborated previous observations that
in vitro
killing by piperacillin was significantly reduced against a dense bacterial inoculum. This phenomenon can be reasonably captured by our proposed mathematical model, and it may improve prediction of bacterial response to various drug exposures in future investigations.
Glyoxyl analogs of indole phytoalexins: Synthesis and anticancer activity
Authors: Kutschy Peter , Sýkora Andrej , Čurillová Zuzana , Repovská Mária , Pilátová Martina , Mojžiš Ján , Mezencev Roman , Pazdera Pavel , Hromjáková Tatiana
Published: August 2010

Glyoxyl analogs of indole phytoalexins brassinin, 1-methoxybrassinin, brassitin, 1-methoxybrassitin and 1-methoxybrassenin B were prepared, using (1H-indol-3-yl)-, (1-methoxyindol-3-yl)- and [1-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)indol-3-yl]glyoxyl chlorides as starting compounds. Synthesized products were examined for their antiproliferative activity against human cancer cell lines Jurkat (T-cell acute lymphoblastic leukemia), MCF-7 (breast adenocarcinoma, estrogen receptor-positive), MDA-MB-231 (breast adenocarcinoma, estrogen receptor-negative), HeLa (cervical adenocarcinoma), CCRF-CEM cell line (T-cell acute lymphoblastic leukemia) and A-549 cell line (lung adenocarcinoma), and their activity compared with natural phytoalexins and corresponding (1H-indol-3-yl)acetic acid derivatives. The highest potency with IC50 3.3–66.1 μmol l–1 was found for glyoxyl analogs of 1-methoxybrassenin B.
Associations between adolescent seatbelt non-use, normative perceptions and screen media exposure: results from a national US survey
Authors: Dunlop Sally M , Romer Daniel
Published: August 2010

Background

Failure to use seatbelts in motor vehicles is a major source of youth injuries, and previous research has noted the widespread non-use of seatbelts in popular media.

Objectives

To explore whether increased exposure to entertainment screen media was associated with inflated normative perceptions regarding seatbelt non-use, and to determine any associations between normative perceptions and seatbelt non-use.

Methods

A nationally representative telephone survey of school-aged American adolescents (14–17 years, n=915) measuring: screen media exposure; normative perceptions with reference to friends' disapproval of non-use, and prevalence of non-use among friends, school peers and peers; and self-reported seatbelt non-use.

Results

Using structural equation modelling, analyses indicate that, after demographic and individual characteristics relevant to screen media exposure and seatbelt non-use had been controlled for, frequent exposure to entertainment media was associated with positive normative perceptions about seatbelt non-use for boys, but not for girls. Normative perceptions related to friends' and school peers' seatbelt use were associated with seatbelt non-use for both boys and girls.

Conclusions

Attempts to increase adolescent seatbelt use could include public communication campaigns to alter normative perceptions. Broadcasting these campaigns in conjunction with the media that under-represent seatbelt use may be a successful strategy for reducing the influence of such media on male adolescents.
Injury statistics, high risk groups, and individuals: falling through the cracks
Authors: Baker Susan P
Published: August 2010

The Frank A Calderone Prize in Public Health, the pre-eminent award in the field, is overseen by Columbia University's Mailman School of Public Health and presented to an individual who has made ‘a transformational contribution in the field of public health’. The Prize recognises an individual who has accomplished extraordinary distinction in public health and/or who has made a specific contribution which has had long-term national or global implications. On 6 May 2010, the prize was awarded to Susan Baker. This is the first time the Prize has been bestowed upon an injury control researcher.
Expanding CS education; improving software development
Authors: Chi Ed H. , Ortega Ruben
Published: August 2010

http://cacm.acm.org/blogs/blog-cacm/82365

The
Communications
Web site, http://cacm.acm.org, features more than a dozen bloggers in the BLOG@CACM community. In each issue of
Communications
, we'll publish selected posts or excerpts.

twitter

Follow us on Twitter at http://twitter.com/blogCACM

Ed H. Chi writes about the social Web's impact on CS education. Ruben Ortega discusses software and test-driven development.
Brains and bytes
Authors: Lindley David
Published: August 2010

Computational neuroscientists are learning that the brain is like a computer, except when it isn't.
ACM China nearing launch
Authors: Geller Tom
Published: August 2010

ACM's expansion into China will support local professionals and increase Chinese involvement in ACM's international activities.
Objects never?
Authors: Ben-Ari Mordechai
Published: August 2010

Revisiting the Great Objects Debate.
Injecting errors for fun and profit
Authors: Chessin Steve
Published: August 2010

Error-detection and correction features are only as good as our ability to test them.
Thinking clearly about performance, part 1
Authors: Millsap Cary
Published: August 2010

Improving the performance of complex software is difficult, but understanding some fundamental principles can make it easier.
Performance evaluation and model checking join forces
Authors: Baier Christel , Haverkort Boudewijn R. , Hermanns Holger , Katoen Joost-Pieter
Published: August 2010

A call for the perfect marriage between classical performance evaluation and state-of-the-art verification techniques.
Future Tense: Little brother Is watching
Authors: Bear Greg
Published: August 2010

Future Tense, one of the revolving features on this page, presents stories and essays from the intersection of computational science and technological speculation, their boundaries limited only by our ability to imagine what will and could be. In a world of technology and fear, the public gets to know what it wants to know... and more than it can possibly digest.
Reflexes
Authors: Spring Jesper Honig , Pizlo Filip , Privat Jean , Guerraoui Rachid , Vitek Jan
Published: August 2010

Achieving submillisecond response times in a managed language environment such as Java or C# requires overcoming significant challenges. In this article, we propose Reflexes, a programming model and runtime system infrastructure that lets developers seamlessly mix highly responsive tasks and timing-oblivious Java applications. Thus enabling gradual addition of real-time features, to a non-real-time application without having to resort to recoding the real-time parts in a different language such as C or Ada. Experiments with the Reflex prototype implementation show that it is possible to run a real-time task with a period of 45 μs with an accuracy of 99.996% (only 0.001% worse than the corresponding C implementation) in the presence of garbage collection and heavy load ordinary Java threads.
Audio-visual atoms for generic video concept classification
Authors: Jiang Wei , Cotton Courtenay , Chang Shih-Fu , Ellis Dan , Loui Alexander C.
Published: August 2010

We investigate the challenging issue of joint audio-visual analysis of generic videos targeting at concept detection. We extract a novel local representation, Audio-Visual Atom (AVA), which is defined as a region track associated with regional visual features and audio onset features. We develop a hierarchical algorithm to extract visual atoms from generic videos, and locate energy onsets from the corresponding soundtrack by time-frequency analysis. Audio atoms are extracted around energy onsets. Visual and audio atoms form AVAs, based on which discriminative audio-visual codebooks are constructed for concept detection. Experiments over Kodak's consumer benchmark videos confirm the effectiveness of our approach.
LiveSky
Authors: Yin Hao , Liu Xuening , Zhan Tongyu , Sekar Vyas , Qiu Feng , Lin Chuang , Zhang Hui , Li Bo
Published: August 2010

We present the design and deployment experiences with
LiveSky
, a commercial hybrid CDN-P2P live streaming system, which inherits the best of both CDN and P2P. We address several key challenges, including: 1) ease of integration with existing CDN infrastructure, 2) dynamic resource scaling while guaranteeing quality-of-service, 3) providing good user experience, ensuring network friendliness and upload fairness.
LiveSky
has been used for several large-scale live streaming events in China. Our evaluation results from real-world indicate that such a hybrid CDN-P2P system provides quality and performance comparable to a CDN and effectively scales the system capacity.
ELVIS
Authors: Money Arthur G. , Agius Harry
Published: August 2010

Video summaries present the user with a condensed and succinct representation of the content of a video stream. Usually this is achieved by attaching degrees of importance to low-level image, audio and text features. However, video content elicits strong and measurable physiological responses in the user, which are potentially rich indicators of what video content is memorable to or emotionally engaging for an individual user. This article proposes a technique that exploits such physiological responses to a given video stream by a given user to produce Entertainment-Led VIdeo Summaries (ELVIS). ELVIS is made up of five analysis phases which correspond to the analyses of five physiological response measures: electro-dermal response (EDR), heart rate (HR), blood volume pulse (BVP), respiration rate (RR), and respiration amplitude (RA). Through these analyses, the temporal locations of the most entertaining video subsegments, as they occur within the video stream as a whole, are automatically identified. The effectiveness of the ELVIS technique is verified through a statistical analysis of data collected during a set of user trials. Our results show that ELVIS is more consistent than RANDOM, EDR, HR, BVP, RR and RA selections in identifying the most entertaining video subsegments for content in the comedy, horror/comedy, and horror genres. Subjective user reports also reveal that ELVIS video summaries are comparatively easy to understand, enjoyable, and informative.
Word level automatic alignment of music and lyrics using vocal synthesis
Authors: Maddage Namunu C. , Sim Khe Chai , Li Haizhou
Published: August 2010

We propose a signal-based approach instead of the commonly used model-based approach, to automatically align vocal music with text lyrics at the word level. In this approach, we use a text-to-speech system to synthesize the singing voice according to the lyrics. In this way, aligning the music signal with the corresponding text lyrics becomes the alignment of two audio signals. This study uses the results of music information modeling and singing voice synthesis. In music information modeling, we study different music representation strategies for music segmentation, music region indexing and region content descriptions; in singing voice synthesis, we generate singing voice by making use of music knowledge to approximate the target vocal line in terms of tempo. The experimental results on a 20-song database show 26.3% and 36.1% word level alignment error rates at eighth note and sixteenth note alignment tolerances respectively. The proposed approach presents an alternative and effective solution to music-lyrics alignment which may require less training dataset.
Efficient delivery of on-demand video streams to heterogeneous receivers
Authors: Qudah Bashar , Sarhan Nabil J.
Published: August 2010

The number of video streams that can be serviced concurrently is highly constrained by the required real-time and high-rate transfers of multimedia data. Resource sharing techniques, such as Batching, Patching, and Earliest Reachable Merge Target (ERMT), can be used to address this problem by utilizing the multicast facility, which allows multiple requests to share the same set of server and network resources. They assume, however, that all clients have the same available download bandwidth and buffer space. We study how to efficiently support clients with varying available download bandwidth and buffer space, while delivering data in a client-pull fashion using enhanced resource sharing. In particular, we propose three
hybrid solutions
to address the variability in the download bandwidth among clients:
Simple Hybrid Solution
(SHS),
Adaptive Hybrid Solution
(AHS), and
Enhanced Hybrid Solution
(EHS). SHS simply combines Batching with either Patching or ERMT, leading to two alternatives:
SHS-P
and
SHS-E
, respectively. Batching is used for clients with bandwidth lower than double the video playback rate, and Patching/ERMT is used for the rest. In contrast, AHS and EHS classify clients into multiple bandwidth classes and service them accordingly. AHS employs a new stream type, called
adaptive stream
, and EHS employs an
enhanced adaptive stream
type to serve clients with bandwidth capacities ranging between the video playback rate and double that rate. AHS and EHS employ adaptive streams or enhanced adaptive streams in conjunction with Batching and Patching or ERMT, leading to four possible schemes: AHS-P, AHS-E, EHS-P, and EHS-E. Moreover, we consider the variability of the available buffer space among clients. Furthermore, we study how the waiting playback requests for different videos can be scheduled for service in the heterogeneous environment, capturing the variations in both the client bandwidth and buffer space. We evaluate the effectiveness of the proposed solutions and analyze various scheduling policies through extensive simulation.
Source traffic analysis
Authors: Gomes João V. P. , Inácio Pedro R. M. , Lakic Branka , Freire Mário M. , Da Silva Henrique J. A. , Monteiro Paulo P.
Published: August 2010

Traffic modeling and simulation plays an important role in the area of Network Monitoring and Analysis, for it provides practitioners with efficient tools to evaluate the performance of networks and of their elements. This article focus on the traffic generated by a single source, providing an overview of what was done in the field and studying the statistical properties of the traffic produced by a personal computer, including analysis of the autocorrelation structure. Different distributions were fitted to the interarrival times, packet sizes, and byte count processes with the goal of singling out the ones most suitable for traffic generation.
Design and development of a sensor model for coalmines
Authors: A.H Srinivasa , Varaprasad G.
Published: August 2010

Wireless sensor network has a large number of sensors, which is used to collect the data from the environments. The sensor devices have a limited energy, memory, transmission range, and computation power. In this paper, we present a model called design and development of a sensor model for coalmines. The proposed model automatically detects the harmful gases such as Methane and Carbon Dioxide using PLS41 and KGJ sensors. It sends the sensing data to the control room through support node over the network. The control room takes necessary steps to prevent the accidents by considering threshold values of gasses. The proposed model is an efficient method to reduce the control message packets over the network.
Leakage-aware real-time scheduling for maximal temperature minimization
Authors: Quan Gang , Ren Shangping
Published: August 2010

Thermal management problem has become a prominent issue as power consumption continues to grow exponentially. The leakage/temperature dependency becomes critical in power and thermal aware design as the processor continues to evolve into the the deep sub-micron domain. This paper seeks to explore fundamental principles in thermal aware design when taking the leakage/temperature dependency into considerations. We show and formally prove that, under certain realistic conditions, using the lowest constant processor speed that can guarantee deadlines of all real-time tasks is an optimal method to minimize the maximal temperature for a real-time system. We also use empirical results to justify the validation of this conclusion. We then discuss the possible future extension of this work.
A design science based evaluation framework for patterns
Authors: Petter Stacie , Khazanchi Deepak , Murphy John D.
Published: August 2010

Patterns were originally developed in the field of architecture as a mechanism for communicating good solutions to recurring classes of problems. Since then, many researchers and practitioners have created patterns to describe effective solutions to problems associated with disparate areas such as virtual project management, human-computer interaction, software development and engineering, and design science research. We believe that the development of patterns is a design science activity in which an artifact (i.e., a pattern) is created to communicate about and improve upon the current state-of-practice. Design science research has two critical components, creation and evaluation of an artifact. While many patterns have been created, few, if any, have been evaluated in this sense. In this paper, we propose a framework to evaluate patterns in any domain and provide examples of how to use the evaluation framework. This process of evaluation could help researchers refine extant patterns and improve the possibility of creating sustainable best practices for a given domain. We believe this evaluation framework begins an important dialogue related to the evaluation of patterns as artifacts of design science research. We draw upon the literature associated with patterns, evaluation of design science research, and research methods to develop this framework for evaluating patterns in a more consistent and rigorous manner.
Volunteers' participation in open source software development
Authors: Xu Bo , Jones Donald R.
Published: August 2010

Open source software comprises a revolutionary new model of software development and distribution. Widespread Internet access in the early 1990s led to a dramatic acceleration of open source activity; but the success of a community open source project depends on the developers' voluntary participation. This paper investigates the social-relational factors, including developers' identification and obligation, shared goals, cognitive and affective trust, and their effects on open source software developer's participation. Data were collected from voluntary developers in open source projects. The research findings show that the social-relational factors are very important to promote developer's participation in an open source project. This research contributes empirically to the body of open source software research, and has practical implications for open source software development.
Dynamic acceleration management for SystemC emulation
Authors: Sirowy Scott , Huang Chen , Vahid Frank
Published: August 2010

Field-programmable gates arrays (FPGAs) have recently been used to emulate SystemC descriptions. Emulation of SystemC descriptions allows for in-system testing, and has been shown to compare favorably with SystemC simulations on a PC when acceleration engines are employed. A limit on the number of acceleration engines that can fit on a SystemC emulation platform creates new dynamic management problems involving decisions as to when and which acceleration engines to load with SystemC bytecode. We define an acceleration management problem for SystemC emulation platforms. In contrast to previous works that focus on statically improving SystemC (and the more general event-driven) simulations, we utilize dynamic online algorithms to manage the use of a limited number of SystemC acceleration engines in an emulation framework, where the kernel must adapt and react to a dynamically changing event queue. We test several online heuristics, and show that we can achieve 14X improvement over software-only emulation and 3.8X over statically preloading SystemC acceleration engines.
Enabling self-adaptivity in component-based streaming applications
Authors: Derin Onur , Ferrante Alberto
Published: August 2010

Self-adaptivity is the capability of a system to adapt itself dynamically to achieve its goals. By means of this mechanism the system is able to autonomously modify its behavior or the way in which applications are run and implemented to achieve the goals set.

In this paper we propose a framework that uses a componentbased approach to implement self-adaptivity at application level. By using this mechanism, the framework provides the ability to perform both adaptation on the structure of the application (i.e., how the components are connected together) and on internal parameters of each component. At application level, there is a mechanism to monitor different parameters and to check whether the system is meeting the assigned goals or not. A controller drives adaptations when goals are not met.
Defective female reproductive function in 1,25(OH)2D-deficient mice results from indirect effect mediated by extracellular calcium and/or phosphorus
Authors: Sun Weiwei , Xie Hui , Ji Ji , Zhou Xiaojie , Goltzman David , Miao Dengshun
Published: August 2010

We used mice with targeted deletion of 25-hydroxyvitamin D 1α-hydroxylase [1α(OH)ase−/−] to investigate the effects of calcium and phosphorus on defects in the reproductive system of 1,25-dihydroxyvitamin D [1,25(OH)2D]-deficient female mice. The 1α(OH)ase−/− mice and their wild-type littermates were fed either a normal diet or a rescue diet (high calcium, phosphate, and lactose) starting from weaning until 3 mo of age. We then determined serum calcium and phosphorus levels, assessed gonadotropin and gonadal hormone production, and evaluated folliculogenesis, corpus luteum formation, ovarian angiogenesis, uterus development, and fertility. Results showed that hypocalcemic and hypophosphatemic female 1α(OH)ase−/− mice developed infertility accompanied by decreased estrogen and progestogen levels, elevated follicle-stimulating hormone and luteinizing hormone levels, defects in follicular development and corpus luteum formation, uterine hypoplasia, and decreased ovarian expression of angiogenic factors including vascular endothelial growth factor (VEGF), angiopoietin-1 and -2, and Tie-2. When serum calcium and phosphorus were normalized by the rescue diet, the defective reproductive phenotype in the female 1α(OH)ase−/− mice, including the dysfunction in the hypothalamic-pituitary-ovarian axis, and ovarian angiogenesis were reversed. These results indicate that the infertility seen in 1,25(OH)2D-deficient mice is not a direct effect of active vitamin D deficiency on the reproductive system but is an indirect effect mediated by extracellular calcium and phosphorus.
Molecular Mechanisms and Genome-Wide Aspects of PPAR Subtype Specific Transactivation
Authors: Bugge Anne , Mandrup Susanne
Published: August 2010

The peroxisome proliferator-activated receptors (PPARs) are central regulators of fat metabolism, energy homeostasis, proliferation, and inflammation. The three PPAR subtypes, PPAR, /, and activate overlapping but also very different target gene programs. This review summarizes the insights into PPAR subtype-specific transactivation provided by genome-wide studies and discusses the recent advances in the understanding of the molecular mechanisms underlying PPAR subtype specificity with special focus on the regulatory role of AF-1.
A Second‐Order Boundary Value Problem with Nonlinear and Mixed Boundary Conditions: Existence, Uniqueness, and Approximation
Authors: Zhou Zheyan , Shen Jianhe
Published: August 2010

A second‐order boundary value problem with nonlinear and mixed two‐point boundary conditions is considered, Lx = f(t, x, x′), t ∈ (a, b), g(x(a), x(b), x′(a), x′(b)) = 0, x(b) = x(a) in which L is a formally self‐adjoint second‐order differential operator. Under appropriate assumptions on L, f, and g, existence and uniqueness of solutions is established by the method of upper and lower solutions and Leray‐Schauder degree theory. The general quasilinearization method is then applied to this problem. Two monotone sequences converging quadratically to the unique solution are constructed.
SpaDiversity among MRSA and MSSA Strains ofStaphylococcus aureusin North of Iran
Authors: Shakeri Fatemeh , Shojai Abolfath , Golalipour Masoud , Rahimi Alang Somaye , Vaez Hamid , Ghaemi Ezzat Allah
Published: August 2010

Protein A ofStaphylococcus aureusis a pathogenic factor whose encoding gene,spa, shows a variation in length in different strains. In this study thespagene variation inS. aureusisolated from healthy carriers and patients was studied, We also compared this variation among MRSA with MSSA strains. 208 strains ofStaphylococcus aureuswhich we were isolated from Gorgan, north of Iran were studied, 121 cases from patients and 87 cases from healthy carriers, 59 out of them wereMRSAand 149MSSA. Samples DNA were extracted and amplified by specific primer ofspagene. In 4 (3.8%) strains of them nospagene was detected, and 10.6% had a dual band (1200 and 1400 bp). In strains with one band, the length ofspagene differed from 1150 to 1500 bp. The most prevalent length was 1350–1400 bp (37%). The frequencies of shortspabands (1150–1200 bp) in patients strains were significantly higher. In 4 (3.8%) strains of them nospagene was detected, and 10.6% had a dual band (1200 and 1400 bp). In strains with one band, the length ofspagene differed from 1150 to 1500 bp. The most prevalent length was 1350–1400 bp (37%). The frequencies of shortspabands (1150–1200 bp) in patients strains were significantly higher. Thespagene length of 1350–1400 bp in MSSA was more than in MRSA strains (P<.05). The average length ofspain isolated strains from urinary tract infections was more than others. It is concluded that the length ofspagene depends either on resistance to Methicillin or the source ofS. aureusisolation.
Environmental Degradation and Durability of Epoxy‐Clay Nanocomposites
Authors: Singh Raman P. , Khait Mikhail , Zunjarrao Suraj C. , Korach Chad S. , Pandey Gajendra
Published: August 2010

This experimental investigation reports on the durability of epoxy‐clay nanocomposites upon exposure to multiple environments. Nanocomposites are fabricated by mixing the clay particles using various combinations of mechanical mixing, high‐shear dispersion, and ultrasonication. Clay morphology is characterized using X‐ray diffraction and transmission electron microscopy. Specimens of both neat epoxy and the epoxy‐clay nanocomposite are subjected to two environmental conditions: combined UV radiation and condensation on 3‐hour repeat cycle and constant temperature‐humidity, for a total exposure duration of 4770 hours. The presence of nanoscale clay inhibits moisture uptake, as demonstrated by exposure to constant temperature‐humidity. Nonetheless, both materials lose mass under exposure to combined UV radiation and condensation due to the erosion of epoxy by a synergistic process. Surprisingly, the epoxy‐clay specimens exhibit greater mass loss, as compared to neat epoxy. Mechanical testing shows that either environment does not significant affect the flexure modulus of either material. On the other hand, both materials undergo degradation in flexural strength when exposed to either environment. However, the epoxy‐clay nanocomposite retains 37% more flexure strength than the neat epoxy after 4072 hours of exposure.