| 1. |
- Khan, Bakht Yawar A., et al.
(författare)
-
A Study on Serum Biochemistry and Hematological Profiling of Blue Rock Pigeon (Columba livia) in Multan (Punjab, Pakistan)
- 2011
-
Ingår i: Pakistan Journal of Zoology. - 0030-9923. ; 43:5, s. 1012-1014
-
Tidskriftsartikel (refereegranskat)abstract
- Thirty wild blue rock pigeons (Columba livia) were caught from Multan city (Pakistan). Hematological values were established for total red blood cells, total white blood cells, packed cell volume, hemoglobin concentration, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and differential leukocyte count. Serum bio chemistry values were determined for glucose (294 +/- 95.1), urea (17.9 +/- 4.9 mg/di), cholesterol (250.3 +/- 57.2 mg/di), creatinine (0.41 +/- 0.2 mg/dl), lactate dehydrogenase (1069 +/- 581), total protein (9.8 +/- 0.7 mg/dl), alanine aminotransferase (75.9 +/- 64.3) and aspratate aminotransferase (297.2 +/- 177) as indicator of bird health and can be used in the future as a reference values in hematology and serum biochemistry of blue rock pigeon.
|
|
| 2. |
- Raykova, Doroteya, et al.
(författare)
-
Autosomal Recessive Transmission of a Rare KRT74 Variant Causes Hair and Nail Ectodermal Dysplasia : Allelism with Dominant Woolly Hair/Hypotrichosis
- 2014
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:4, s. e93607-
-
Tidskriftsartikel (refereegranskat)abstract
- Pure hair and nail ectodermal dysplasia (PHNED) comprises a heterogeneous group of rare heritable disorders characterized by brittle hair, hypotrichosis, onychodystrophy and micronychia. Autosomal recessive (AR) PHNED has previously been associated with mutations in either KRT85 or HOXC13 on chromosome 12p11.1-q14.3. We investigated a consanguineous Pakistani family with AR PHNED linked to the keratin gene cluster on 12p11.1 but without detectable mutations in KRT85 and HOXC13. Whole exome sequencing of affected individuals revealed homozygosity for a rare c.821T> C variant (p.Phe274Ser) in the KRT74 gene that segregates AR PHNED in the family. The transition alters the highly conserved Phe274 residue in the coil 1B domain required for long-range dimerization of keratins, suggesting that the mutation compromises the stability of intermediate filaments. Immunohistochemical (IHC) analyses confirmed a strong keratin-74 expression in the nail matrix, the nail bed and the hyponychium of mouse distal digits, as well as in normal human hair follicles. Furthermore, hair follicles and epidermis of an affected family member stained negative for Keratin-74 suggesting a loss of function mechanism mediated by the Phe274Ser substitution. Our observations show for the first time that homozygosity for a KRT74 missense variant may be associated with AR PHNED. Heterozygous KRT74 mutations have previously been associated with autosomal dominant woolly hair/ hypotrichosis simplex (ADWH). Thus, our findings expand the phenotypic spectrum associated with KRT74 mutations and imply that a subtype of AR PHNED is allelic with ADWH.
|
|
| 3. |
- Aibinu, A.M., et al.
(författare)
-
Vascular intersection detection in retina fundus images using a new hybrid approach
- 2010
-
Ingår i: Computers in Biology and Medicine. - : Elsevier. - 0010-4825 .- 1879-0534. ; 40:1, s. 81-89
-
Tidskriftsartikel (refereegranskat)abstract
- The use of vascular intersection aberration as one of the signs when monitoring and diagnosing diabetic retinopathy from retina fundus images (FIs) has been widely reported in the literature. In this paper, a new hybrid approach called the combined cross-point number (CCN) method able to detect the vascular bifurcation and intersection points in FIs is proposed. The CCN method makes use of two vascular intersection detection techniques, namely the modified cross-point number (MCN) method and the simple cross-point number (SCN) method. Our proposed approach was tested on images obtained from two different and publicly available fundus image databases. The results show a very high precision, accuracy, sensitivity and low false rate in detecting both bifurcation and crossover points compared with both the MCN and the SCN methods.
|
|
| 4. |
- Ali, Muhammad Taha, et al.
(författare)
-
Design of High Efficiency Wireless Power Transmission System at Low Resonant Frequency
- 2014
-
Konferensbidrag (refereegranskat)abstract
- This paper presents a novel design of a wireless power transmission system which transfers an appreciable amount of electrical power wirelessly using low resonant frequency, with an excellent efficiency, and has a very low cost implementation. The designs of induction coils at both source and receiver sides are also presented in this paper. The mechanism for power transmission is through electro-magnetic induction. Also an immense knowledge of electronics was applied in order to design the source and receiver between which this transfer took place. In order to realize this method an AC-AC converter, and AC-DC rectifier were used at source and receiver sides respectively along with the resonant circuits. The work was carried out by the experimental setup and results demonstrate that proposed system design can successfully transfer the amount of power that can be used in many practical applications.
|
|
| 5. |
- Anwar, Muhammad Ikram, et al.
(författare)
-
Prevalence of active hepatitis C virus infections among general public of Lahore, Pakistan
- 2013
-
Ingår i: Virology Journal. - 1743-422X. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Background: To find out the prevalence of active hepatitis C virus (HCV) infections among general public in Lahore city, since data concerning the prevalence of active HCV in this city is currently unavailable. Methods: Blood samples were collected randomly from individuals visiting different clinical laboratories in Lahore. Serum was separated and processed by nested PCR qualitative assay for the detection of HCV RNA. The samples were categorized into different age groups on the basis of pre-test questionnaires in order to record the age-wise differences regarding the prevalence of active HCV. Data were analyzed statistically using Chi-Square test. Results: Out of the 4246 blood samples analyzed in this study, 210 were confirmed to be positive for active HCV infection. Gender-wise active HCV prevalence revealed no significant difference [OR = 1.10 CI = (0.83-1.46), p > 0.05]. However, among the age groups the highest prevalence was observed in the age groups 20-29 (7.7%) and 30-39 years (6.4%) with odds of prevalence of 14.8% (OR = 2.48, CI = (1.40-4.38), p < 0.05) and 10.3% (OR = 2.03, CI = (1.10-3.71), respectively. In age groups above 40 years (40-49, 50-59 and >59 years), a decrease in levels of active HCV prevalence was observed. Conclusions: Among tested samples, 4.9% of the subjects were confirmed to harbour active HCV infections and the middle aged population in Lahore was found to be at a higher risk of the HCV ailments compared to both their younger and older peers.
|
|
| 6. |
- Atluri, Rambabu, et al.
(författare)
-
Self-Assembly Mechanism of Folate-Templated Mesoporous Silica
- 2013
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 29:38, s. 12003-12012
-
Tidskriftsartikel (refereegranskat)abstract
- A method to form ordered mesoporous silica based on the use of folate supramolecular templates has been developed. Evidence based on in situ small-angle X-ray scattering (SAXS), electron microscopy, infrared spectroscopy, and in situ conductivity measurements are used to investigate the organic inorganic interactions and synthesis mechanism. The behavior of folate molecules in solution differs distinctively from that of surfactants commonly used for the preparation of ordered mesoporous silica phases, notably with the absence of a critical micellar concentration. In situ SAXS studies reveal fluctuations in X-ray scattering intensities consistent with the condensation of the silica precursor surrounding the folate template and the growth of the silica mesostructure in the initial stages. High-angle X-ray diffraction shows that the folate template is well-ordered within the pores even after a few minutes of synthesis. Direct structural data for the self-assembly of folates into chiral tetramers within the pores of mesoporous silica provide evidence for the in register stacking of folate tetramers, resulting in a chiral surface of rotated tetramers, with a rotation angle of 30 degrees. Additionally, the self-assembled folates within pores were capable of adsorbing a considerable amount of CO2 gas through the cavity space of the tetramers. The study demonstrates the validity of using a naturally occurring template to produce relevant and functional mesoporous materials.
|
|
| 7. |
- Gencel, Cigdem, et al.
(författare)
-
A Decision Support Framework for Metric Selection in Goal-Based Measurement Programs : GQM-DSFMS
- 2013
-
Ingår i: Journal of Systems and Software. - : Elsevier. - 0164-1212. ; 86:12, s. 3091-3108
-
Tidskriftsartikel (refereegranskat)abstract
- Software organizations face challenges in managing and sustaining their measurement programs over time. The complexity of measurement programs increase with exploding number of goals and metrics to collect. At the same time, organizations usually have limited budget and resources for metrics collection. It has been recognized for quite a while that there is the need for prioritizing goals, which then ought to drive the selection of metrics. On the other hand, the dynamic nature of the organizations requires measurement programs to adapt to the changes in the stakeholders, their goals, information needs and priorities. Therefore, it is crucial for organizations to use structured approaches that provide transparency, traceability and guidance in choosing an optimum set of metrics that would address the highest priority information needs considering limited resources. This paper proposes a decision support framework for metrics selection (DSFMS) which is built upon the widely used Goal Question Metric (GQM) approach. The core of the framework includes an iterative goal-based metrics selection process incorporating decision making mechanisms in metrics selection, a pre-defined Attributes/Metrics Repository, and a Traceability Model among GQM elements. We also discuss alternative prioritization and optimization techniques for organizations to tailor the framework according to their needs. The evaluation of the GQM-DSFMS framework was done through a case study in a CMMI Level 3 software company.
|
|
| 8. |
- Golsteijn, Laura, et al.
(författare)
-
Assessing predictive uncertainty in comparative toxicity potentials of triazoles
- 2014
-
Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268 .- 1552-8618. ; 33:2, s. 293-301
-
Tidskriftsartikel (refereegranskat)abstract
- Comparative toxicity potentials (CTPs) quantify the potential ecotoxicological impacts of chemicals per unit of emission. They are the product of a substance's environmental fate, exposure, and hazardous concentration. When empirical data are lacking, substance properties can be predicted. The goal of the present study was to assess the influence of predictive uncertainty in substance property predictions on the CTPs of triazoles. Physicochemical and toxic properties were predicted with quantitative structure-activity relationships (QSARs), and uncertainty in the predictions was quantified with use of the data underlying the QSARs. Degradation half-lives were based on a probability distribution representing experimental half-lives of triazoles. Uncertainty related to the species' sample size that was present in the prediction of the hazardous aquatic concentration was also included. All parameter uncertainties were treated as probability distributions, and propagated by Monte Carlo simulations. The 90% confidence interval of the CTPs typically spanned nearly 4 orders of magnitude. The CTP uncertainty was mainly determined by uncertainty in soil sorption and soil degradation rates, together with the small number of species sampled. In contrast, uncertainty in species-specific toxicity predictions contributed relatively little. The findings imply that the reliability of CTP predictions for the chemicals studied can be improved particularly by including experimental data for soil sorption and soil degradation, and by developing toxicity QSARs for more species. (c) 2013 SETAC
|
|
| 9. |
- Iqbal, Muhammad Imran, et al.
(författare)
-
A Framework for Error Protection of Region of Interest Coded Images and Videos
- 2011
-
Ingår i: Signal processing. Image communication. - : Elsevier. - 0923-5965 .- 1879-2677. ; 26:4-5, s. 236-249
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, we propose a framework for unequal error protection (UEP) of image and video streaming over a wireless channel. Our framework of allocating the parity symbols associated with error control coding to the image or video codestream takes advantage of the different levels of importance that particular spatial regions of visual multimedia content has to human observers. As such, it provides stronger protection against transmission impairments to those parts of an image or video stream that correspond to the regions of interest (ROIs) while weaker protection is applied to the background (BG). For this purpose, an image or video stream represented by a sequence of packets is split into smaller cells in such a way that certain cells contain the parts of a codestream that represent ROIs and the last cell carries solely BG information. The available parity budget obtained from the given code rate is then distributed among these cells based on their contribution to the overall perceptual quality of a reconstructed image or video. A dynamic programming approach is utilized to facilitate optimal allocation of parity to ROIs and BG for ROI based UEP. The performance of the proposed ROI based UEP scheme in terms of a objective perceptual quality metric is analyzed and compared with both the optimal UEP without ROI processing and equal error protection (EEP) using the structural similarity (SSIM) index. Performance results validate the effectiveness of our framework and the superior performance of the proposed UEP scheme compared to EEP. The performance of the proposed UEP scheme matches well with that of the optimal UEP without ROI processing, especially, for multiple spatial description image and video coding while computational complexity can be kept much lower.
|
|
| 10. |
- Iqbal, Muhammad Imran, et al.
(författare)
-
Error Protection for Wireless Imaging : Providing a Trade-off Between Performance and Complexity
- 2010
-
Konferensbidrag (refereegranskat)abstract
- In this paper, we propose a number of error protection schemes for wireless imaging ranging from simple but less efficient equal error protection to very complex yet optimal error protection. The main objective is to facilitate tradeoffs between performance and complexity in choosing an error protection scheme. Our technique provides the system designer with a number of solutions from which the application can choose those that best suits the available resources such as processing power and data rate. For this purpose, an image codestream is split into smaller cells each having a certain number of packets while the available parity symbols from the deployed error protection are optimally allocated to these cells. Subsequently, the parity symbols allocated to these cells are distributed among the packets that constitute each of these cell. Finally, the error control codes for every packet are determined based on the number of parity symbols allocated to each packet. Larger cells provide less complex but also less efficient error protection while smaller cells result in a better error protection performance but at the cost of increased complexity. Simulation results validate the effectiveness of the considered technique in providing the desired performances-complexity trade-off. To obtain better correlation with human perception, performance is evaluated in terms of objective perceptual quality metrics.
|
|
| 11. |
- Iqbal, Muhammad Imran
(författare)
-
On Perception-Based Error Protection for Mobile Multimedia
- 2012
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Representation of multimedia requires large amounts of data. Therefore, multimedia source signals are compressed to reduce the data rate that would otherwise be required for its transmission. However, compression renders multimedia data more vulnerable to transmission errors. Therefore, error protection is needed when transmitting multimedia to mobile users over wireless channels. As channel coding adds parity symbols to the data for error protection, which in turn increases transmission data rate, efficient utilization of this added parity budget becomes a key for insuring quality of service for mobile multimedia. Computing the optimal parity allocation among packets of a multimedia stream may not be possible in realtime due to the huge number of ways the parity can be assigned to these packets. Therefore, it is important to design powerful error protection schemes while imposing low computational and memory demands on the system. This is particularly true for systems having limited resources, such as mobile handheld devices. Given that human beings are the final judges on the quality of multimedia services, it will also be beneficial to use perceptual quality metrics that correlate well with human perception when evaluating different error protection schemes. In this work, we have considered the above aspects when designing error protection for mobile multimedia: Providing near optimal performance while keeping complexity low; designing and evaluating of error protection schemes based on perceptual quality metrics. The thesis is divided into five parts. In the first part, region of interest (ROI) identification, coding and advantages of ROI coding are investigated. In addition, a framework is proposed for using ROI coding in wireless imaging. The second part provides a number of unequal error protection (UEP) schemes for wireless imaging ranging from very simple and less efficient equal error protection to very complex yet optimal error protection. The proposed error protection schemes provide an excellent trade-off between performance and omplexity. In the third part, a framework for perception-based error protection of images and video streams is proposed. This framework is based on the fact that the human visual system is more sensitive to quality degradation in the ROI compared to the background. The proposed error protection scheme provides excellent performance. Part four deals with realtime systems and/or systems having limited memory and processing resources. Specifically, an UEP is proposed for wireless imaging systems which provides near optimal performance and puts very low processing/memory demands on the systems. Finally, in the fifth part, optimal UEP is analyzed. Based on the analysis, optimal UEP is modeled using several mathematical models. Each of the considered models is evaluated for its fitness in providing error protection. The simulation results show that most of the investigated models give excellent performance.
|
|
| 12. |
- Iqbal, Muhammad Imran
(författare)
-
Preferential Coding for Mobile Multimedia Services
- 2010
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Different parts of source encoded multimedia streams such as those associated with standard image or video formats possess different levels of importance with respect to their contribution to the quality of the reconstructed image or video. This unequal importance among data within a codestream gives rise to preferential treatment of the more significant parts of the codestream compared to the less important parts. Similarly, visual information offered by certain regions of an image or video may attract viewer’s attention more than other parts of the viewing area. As a consequence, preferential treatment of important data and information can play a vital role in mobile multimedia services in order to preserve satisfactory quality of service under the harsh conditions of a band-limited, error-prone wireless channel. In this thesis, we therefore, investigate how preferential coding can be used to protect multimedia services more efficiently against transmission errors. For this purpose, an error sensitivity analysis of the specific application is utilized as a basis to design efficient unequal error protection (UEP) schemes. The performance of the proposed preferential coding schemes is evaluated using objective perceptual quality metrics in order to account for the fact that humans are the ultimate judges of service quality. The thesis is divided into four parts. In the first part, region of interest (ROI) identification, coding and advantages of ROI coding for different applications are investigated. In addition, a framework is proposed for using ROI coding in wireless imaging. The second part analyses the error sensitivity of wireless JPEG2000 (JPWL) in terms of perceptual quality metrics. It is also shown that using reduced- reference perceptual quality metrics as error sensitivity descriptor (ESD) in JPWL increases the effectiveness of ESD. Specifically, this type of metrics correlates well with subjective quality assessment and provides an additional estimate for the obtained quality. In the third part, two UEP schemes for JPWL are proposed and compared with equal error protection (EEP). Their performance is evaluated in terms of perceptual quality metrics such as structural similarity index and the visual information fidelity criterion of the reconstructed image and their benefit over EEP is revealed. Finally, in the fourth part, a framework for optimized preferential coding of ROI based images and videos is proposed. Specifically, a dynamic programming algorithm for optimal parity distribution is provided.
|
|
| 13. |
- Iqbal, Muhammad Imran, et al.
(författare)
-
Quality Assessment of Error Protection Schemes for Wireless JPEG2000
- 2010
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Wireless imaging services suffer large impairments due to the hostile nature of the wireless channel. Given the limited and expensive channel bandwidth and the high data demanding nature of these services, it becomes a challenging task to provide high quality of service in such error prone channels. Clearly, suitable error protection is necessary in order to maintain sufficient quality of these services under various channel conditions. In this report, therefore, we have investigated different channel error protection schemes for a wide range of channel conditions and coding rates. Two unequal error protection (UEP) schemes have been examined for JPEG2000 images exploiting useful features of the JPEG2000 codestream and using the error protection tool set provided by wireless JPEG2000 (JPWL). Taking the importance of the initial codestream packets on the reconstruction of the image at the receiver into account, the first scheme uses all the additional bandwidth resources in protecting the initial packets of the codestream. The rest of the packets, which are of relatively low importance, are transmitted without any parity symbols assigned to them. In the second UEP scheme, the initial parts of the codestream are strongly protected by assigning them an increased amount of parity symbols. In addition, the tail packets of the codestream are also protected but using a weaker error control code compared to the initial packets. The performance of the proposed UEP schemes has been investigated in terms of the peak signal-to-noise ratio as a typical fidelity metric and three perceptual quality metrics, namely, the Lp-norm, the structural similarity index, and the visual information fidelity criterion. Numerical results of the proposed UEP schemes have been compared with conventional equal error protection (EEP) over additive white Gaussian noise (AWGN) channel as well as Rayleigh fading channel in the presence of AWGN. The results reveal the superior performance of the suggested UEP schemes compared to EEP over a range of channel signal-to-noise ratios and code rates.
|
|
| 14. |
- Iqbal, Muhammad Imran, et al.
(författare)
-
Real-Time Unequal Error Protection for Wireless Imaging
- 2011
-
Konferensbidrag (refereegranskat)abstract
- In this paper, we propose a new unequal error protection (UEP) scheme for wireless imaging. Our technique is based on approximating the optimal parity distribution using offline and online processing. For a given parity budget and signal to-noise ratio (SNR), the offline processing is responsible for obtaining the optimal parity distribution and an approximation of it using polynomial curve fitting. Subsequently, in the online processing, the obtained polynomial parameters are used to regenerate the parity distribution curve. Eventually, channel codes are assigned to the packets of the codestream based on the regenerated parity distribution curve. The complexity of the proposed technique is very low which makes it suitable for real-time wireless imaging, especially for mobile devices that have low processing power and operate with very low memory. Despite having very low complexity, the proposed UEP technique gives still close to optimal performance.
|
|
| 15. |
- Iqbal, Muhammad Imran, et al.
(författare)
-
Spatio-Temporal Quality of Experience Trade-offs for Mobile Imaging Applications
- 2010
-
Konferensbidrag (refereegranskat)abstract
- In this paper, we focus on mobile images given in JPEG2000 format and evaluate their spatio-temporal Quality of Experience (QoE). In particular, the trade-of between spatial QoE supported by progressive source encoding and temporal QoE related to network delay as well as initial transmission delay is examined.
|
|
| 16. |
- Iqbal, Muhammad Sarfraz, et al.
(författare)
-
Description and Propagation of Uncertainty in Input Parameters in Environmental Fate Models
- 2013
-
Ingår i: Risk Analysis. - : Wiley. - 0272-4332 .- 1539-6924. ; 33:7, s. 1353-66
-
Tidskriftsartikel (refereegranskat)abstract
- Today, chemical risk and safety assessments rely heavily on the estimation of environmental fate by models. The key compound-related properties in such models describe partitioning and reactivity. Uncertainty in determining these properties can be separated into random and systematic (incompleteness) components, requiring different types of representation. Here, we evaluate two approaches that are suitable to treat also systematic errors, fuzzy arithmetic, and probability bounds analysis. When a best estimate (mode) and a range can be computed for an input parameter, then it is possible to characterize the uncertainty with a triangular fuzzy number (possibility distribution) or a corresponding probability box bound by two uniform distributions. We use a five-compartment Level I fugacity model and reported empirical data from the literature for three well-known environmental pollutants (benzene, pyrene, and DDT) as illustrative cases for this evaluation. Propagation of uncertainty by discrete probability calculus or interval arithmetic can be done at a low computational cost and gives maximum flexibility in applying different approaches. Our evaluation suggests that the difference between fuzzy arithmetic and probability bounds analysis is small, at least for this specific case. The fuzzy arithmetic approach can, however, be regarded as less conservative than probability bounds analysis if the assumption of independence is removed. Both approaches are sensitive to repeated parameters that may inflate the uncertainty estimate. Uncertainty described by probability boxes was therefore also propagated through the model by Monte Carlo simulation to show how this problem can be avoided.
|
|
| 17. |
- Iqbal, Muhammad Sarfraz
(författare)
-
Environmental Modeling and Uncertainty
- 2013
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Environmental fate models are used to evaluate the fate and effects of chemicals for risk assessment. Fate models may be effective and low-cost substitutes for field measurements and are helpful to project future scenarios. Environmental models describe processes for chemical fate largely determined by environmental and chemical-specific parameters. There is uncertainty in such input parameters arising from lack of knowledge and inherent variability in environmental processes. The objectives of this thesis are to demonstrate and evaluate ways to quantify, implement, and reduce uncertainty in chemical-specific input parameters and in the process to improve the overall treatment of uncertainty in environmental modeling. The methods to treat uncertainty were combinations of multimedia environmental modeling, the use of testing and non-testing information in risk assessment, and probabilistic and non-probabilistic measures of uncertainty. This thesis contains six case studies related to chemical safety assessment which illustrate different aspects of treatment of uncertainty in a regulatory context. Dependent on nature of uncertainty and the available information, the approaches to treat uncertainty were probabilistic, non-probabilistic or combinations of these. Some case studies were put into the perspective to support chemical regulation under REACH. In three studies, the contribution of uncertainty in input parameters was evaluated on characteristics of uncertainty in assessed persistence, long-range transport potential and comparative toxicity potentials of chemicals in the environment. In other studies, the focus was on decision making such as prioritization of chemicals for risk assessment and the need for further testing to reduce input uncertainty. The main contributions are useful applications of a broader treatment of uncertainty in environmental modeling that address gaps and quality in available background knowledge. Epistemic uncertainty is treated by filling knowledge gaps using non-testing information from QSARs. Uncertainty in non-testing information is given a probabilistic treatment based on statistical principles of inference. Poor quality of background knowledge, such as sparse data or low confidence in individual QSAR predictions, is treated by non-probabilistic measures. Finally, the suggested treatments of uncertainty are implemented and evaluated in the context of chemical risk assessment.
|
|
| 18. |
|
|
| 19. |
- Iqbal, Muhammad Sarfraz, et al.
(författare)
-
Treatment of Epistemic Uncertainty in Environmental Fate Models –Consequences on Chemical Safety Regulatory Strategies
- 2012
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The practical impact of treatment of epistemic uncertainty on decision making wasillustrated on two kinds of decisions from chemical regulation. First, regulatory strategies derivedfrom a simplified decision model based on toxicity and persistence showed that regulated level ofexposure is more conservative (safe) when uncertainty has been given a non-probabilistictreatment. Persistence and its uncertainty had been assessed by a Level II fugacity model forwhich input parameters had been quantified either by Bayesian probabilities, fuzzy numbers(non-probabilistic), or combinations of these (probability boxes). These findings are restricted tohow we let decision makers respond to uncertainty in model predictions by the chosen set ofdecision rules. Further, the use of either treatment depends on the quality and quantity ofbackground knowledge and the required level of detail on the assessment. In the absence ofexperimentally tested physicochemical endpoints, European chemical regulation REACH allowsthe use of non-testing strategies such as Quantitative Structure-Property Relationships (QSPR) topredict the required information. The second decision problem was to select which chemicalsubstances to prioritize for experimental testing in order to strengthen the background knowledgefor chemical regulation with respect to the uncertainty in QSPR predictions. We found that thevalue of reducing uncertainty, given by the expected gain in net benefit for society, was affectedby its treatment and there were no consistent order of testing of the three compounds. However,value of information is a Bayesian probabilistic approach that, unless developed further, loose itsinterpretability under other treatments of uncertainty. The framework of a predictive model, riskmodel, decision model and value of information analysis provides a computational template forfurther evaluation of the effect of treatment of uncertainty on decision making.
|
|
| 20. |
|
|
| 21. |
- Iqbal, Muhammad Sarfraz, et al.
(författare)
-
Understanding quantitative structure-property relationships uncertainty in environmental fate modeling
- 2013
-
Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268 .- 1552-8618. ; 32:5, s. 1069-1076
-
Tidskriftsartikel (refereegranskat)abstract
- In cases in which experimental data on chemical-specific input parameters are lacking, chemical regulations allow the use of alternatives to testing, such as in silico predictions based on quantitative structure–property relationships (QSPRs). Such predictions are often given as point estimates; however, little is known about the extent to which uncertainties associated with QSPR predictions contribute to uncertainty in fate assessments. In the present study, QSPR-induced uncertainty in overall persistence (POV) and long-range transport potential (LRTP) was studied by integrating QSPRs into probabilistic assessments of five polybrominated diphenyl ethers (PBDEs), using the multimedia fate model Simplebox. The uncertainty analysis considered QSPR predictions of the fate input parameters' melting point, water solubility, vapor pressure, organic carbon–water partition coefficient, hydroxyl radical degradation, biodegradation, and photolytic degradation. Uncertainty in POV and LRTP was dominated by the uncertainty in direct photolysis and the biodegradation half-life in water. However, the QSPRs developed specifically for PBDEs had a relatively low contribution to uncertainty. These findings suggest that the reliability of the ranking of PBDEs on the basis of POV and LRTP can be substantially improved by developing better QSPRs to estimate degradation properties. The present study demonstrates the use of uncertainty and sensitivity analyses in nontesting strategies and highlights the need for guidance when compounds fall outside the applicability domain of a QSPR.
|
|
| 22. |
- Iqbal, Syed Muhammad Zeeshan, et al.
(författare)
-
A Parallel DFS Algorithm for Train Re-scheduling During Traffic Disturbances — Early Results
- 2011
-
Konferensbidrag (refereegranskat)abstract
- Railways are an important part of the infrastructure in most countries. As the railway networks become more and more saturated, even small traffic disturbances can propagate and have severe consequences. In this paper, the train re-scheduling problem is studied in order to minimize the final delay for all trains in the scenarios. We propose a parallel algorithm based on a depth-first search branch-and-bound strategy. The parallel algorithm is compared to a sequential algorithm in terms of the quality of the solution and the number of nodes evaluated, as well as to optimal solutions found by Cplex, using 20 disturbance scenarios. Our parallel algorithm significantly improves the solution for 5 out of 20 disturbance scenarios, as compared to the sequential algorithm.
|
|
| 23. |
- Iqbal, Syed Muhammad Zeeshan, et al.
(författare)
-
A parallel heuristic for fast train dispatching during railway traffic disturbances : Early results
- 2012
-
Konferensbidrag (refereegranskat)abstract
- Railways are an important part of the infrastructure in most countries. As the railway networks become more and more saturated, even small traffic disturbances can propagate and have severe consequences. Therefore, efficient re-scheduling support for the traffic managers is needed. In this paper, the train real-time re-scheduling problem is studied in order to minimize the total delay, subject to a set of safety and operational constraints. We propose a parallel greedy algorithm based on a depth-first branch-and-bound search strategy. A number of comprehensive numerical experiments are conducted to compare the parallel implementation to the sequential implementation of the same algorithm in terms of the quality of the solution and the number of nodes evaluated. The comparison is based on 20 disturbance scenarios from three different types of disturbances. Our results show that the parallel algorithm; (i) efficiently covers a larger portion of the search space by exchanging information about improvements, and (ii) finds better solutions for more complicated disturbances such as infrastructure problems. Our results show that the parallel implementation significantly improves the solution for 5 out of 20 disturbance scenarios, as compared to the sequential algorithm.
|
|
| 24. |
- Iqbal, Syed Muhammad Zeeshan, et al.
(författare)
-
Multi-Strategy Based Train Re-Scheduling During Railway Traffic Disturbances
- 2013
-
Konferensbidrag (refereegranskat)abstract
- Disruptions and delays in railway traffic networks due to different types of disturbances is a frequent problem in many countries. When disruptions occur, the train traffic dispatchers may need to re-schedule the traffic and this is often a very demanding and complicated task. To support the train traffic dispatchers, we propose to use a parallelized multi-strategy based greedy algorithm. This paper presents three different parallelization approaches: (i) Single Strategy with a Partitioned List (i.e. the parallel processes originate from different starting points), (ii) Multiple Strategies with a Non-Partitioned List, and (iii) Multiple Strategies with a Partitioned List. We present an evaluation for a busy part of the Swedish railway network based on performance metrics such as the sum of all train delays at their final destinations and the number of delayed trains. The results show that parallelization helps to improve the solution quality. The parallel approach (iii) that combines all re-scheduling strategies with a partitioned list performs best among the three parallel approaches when minimizing the total final delay. The main conclusion is that the multi-strategy based parallel approach significantly improves the solution for 11 out of 20 disturbance scenarios, as compared to the sequential re-scheduling algorithm. The approach also provides an increased stability since it always delivers a feasible solution in short time.
|
|
| 25. |
- Iqbal, Syed Muhammad Zeeshan, et al.
(författare)
-
ParMiBench : An Open-Source Benchmark for Embedded Multiprocessor Systems
- 2010
-
Ingår i: IEEE Computer Architecture Letters. - : IEEE. - 1556-6056. ; 9:2, s. 45-48
-
Tidskriftsartikel (refereegranskat)abstract
- Multicore processors are the main computing platform in laptops, desktop, and servers today, and are making their way into the embedded systems market also. Using benchmarks is a common approach to evaluate the performance of a system. However, benchmarks for embedded systems have so far been either targeted for a uni-processor environment, e.g., MiBench, or have been commercial, e.g., MultiBench by EEMBC. In this paper, we propose and implement an open source benchmark, ParMiBench, targeted for multiprocessor-based embedded systems. ParMiBench consists of parallel implementations of seven compute intensive algorithms from the uni-processor benchmark suite MiBench. The applications are selected from four domains: Automation and Industry Control, Network, Office, and Security.
|
|
| 26. |
- Javed, Iqbal, et al.
(författare)
-
Photophysical and electrochemical properties and temperature dependent geometrical isomerism in alkyl quinacridonediimines
- 2014
-
Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry. - 1144-0546 .- 1369-9261. ; 38:2, s. 752-761
-
Tidskriftsartikel (refereegranskat)abstract
- Quinacridone diimines 1-10 were synthesized by the condensation of anilines with alkyl substituted quinacridones (QA). Photophysical and electrochemical properties of the compounds were investigated. Unconventional behavior of absorption spectra suggested a decrease in pi(-)conjugation within the QA skeleton as well as lack of extended pi(-)conjugation between the QA skeleton and the N-phenyl rings. A computational study of compounds 1-10, a variable temperature H-1 NMR study of compounds 2, 7 and 10 (for instance), and single crystal X-ray analysis of 2, 3, 6, 7, 8 and 10 indicated that the anomalous behavior is due to the buckled, non-planar structure of the quinacridones. Moreover the molecules existed in two interconvertible geometric isomeric forms at different temperatures. Molecular orbital calculations were performed at B3LYP/6-31+G(d), B3PW91/6-31G(d) and PBEPBE/6-31G(d) levels of theory at B3PW91/6-31G(d) optimized structures for both isomers of all compounds (1-10); the results obtained are in close agreement with the experimentally determined values.
|
|
| 27. |
- Ma'Sum, M. A., et al.
(författare)
-
Automatic fetal organs detection and approximation in ultrasound image using boosting classifier and hough transform
- 2014
-
Ingår i: Proceedings - ICACSIS 2014. - 9781479980758 ; , s. 460-467
-
Konferensbidrag (refereegranskat)abstract
- In this paper we proposed a system for automatic fetal detection and approximation in ultrasound image. We used Adaboost. MH based on Multi Stump Classifier to detect fetal organs in ultrasound. After fetal organ detected, it is approximated using Randomized Hough Transform. Experiments result show that mean accuracy of the fetal organs detection reaches 93.92% with mean kappa coefficient value reaches 0.854 and mean hamming error reaches 0.032. Proposed method has better performance compared to other five methods proposed in previous researches. Fetal Organ shape approximation performance reaches 81% for fetal head, 57% for fetal abdomen, 72% of fetal femur, and 66% of fetal humérus.
|
|
| 28. |
- Rahman, Inayat Ur, et al.
(författare)
-
Cellular and genomic toxicity produced by UV light in Chinese hamster ovary cells
- 2014
-
Ingår i: Pakistan Journal of Pharmaceutical Sciences. - 1011-601X. ; 27:2, s. 295-301
-
Tidskriftsartikel (refereegranskat)abstract
- UVB and UVC toxicity was detected in Chinese Hamster Ovary (CHO) cell lines AA8, UV5 and XEM2 (a V79-derived cell line expressing rat P 450 1A1). Unlike FICZ-HPLC assay that showed induction of CYP1A1 enzyme activity after 20 minutes and 2 hour UVC exposure, the EROD assay showed no difference in cytochrome P450 1A1 (CYP1A1) activity after exposure to different doses of UVB and UVC light. Different cytotoxic and mutagenic effect of photo lesions induced by UVC and UVB light was investigated with the DRAG and HPRT assays, comparing the wild type cell line AA8 and the Nucleotide Excision Repair (NER) deficient cell line UV5. DRAG assay showed a significant difference in UV induced cytotoxicity between UVC and UVB reflecting the larger energy and toxic effect of UVC along with significant difference in UV induced toxicity between AA8 and UV5 cell lines. This was further validated through the HPRT assay, which also showed a significant difference in UVC (5 J/m(2)) induced mutagenic effect between these cell lines. In addition, HPRT assay showed the mutagenic effect of photosensitizer, acetophenone. These results show that UVB and UVC generate serious damage through photo products on DNA, and might induce the metabolic activity of CYP1A1
|
|
| 29. |
- Sahlin, Ullrika, et al.
(författare)
-
Arguments for considering uncertainty in QSAR predictions in hazard and risk assessments
- 2013
-
Ingår i: ATLA (Alternatives to Laboratory Animals). - : SAGE Publications. - 0261-1929. ; 41:1, s. 91-110
-
Tidskriftsartikel (refereegranskat)abstract
- Chemical regulation allows non-in vivo testing (i.e. in silico-derived and in vitro-derived) information to replace experimental values from in vivo studies in hazard and risk assessments. Although non-in vitro testing information on chemical activities or properties is subject to added uncertainty as compared to in vivo testing information, this uncertainty is commonly not (fully) taken into account. Considering uncertainty in predictions from quantitative structure-activity relationships (QSARs), which are a form of non-in vivo testing information, may improve the way that QSARs support chemical safety assessment under the EU Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) system. We argue that it is useful to consider uncertainty in QSAR predictions, as it: a) supports rational decision-making; b) facilitates cautious risk management; c) informs uncertainty analysis in probabilistic risk assessment; d) may aid the evaluation of QSAR predictions in weight-of-evidence approaches; and e) provides a probabilistic model to verify the experimental data used in risk assessment. The discussion is illustrated by using case studies of QSAR integrated hazard and risk assessment from the EU-financed CADASTER project.
|
|
| 30. |
- Zeeshan Iqbal, Syed Muhammad, et al.
(författare)
-
A Comparative Evaluation of Re-scheduling Strategies for Train Dispatching during Disturbances
- 2012
-
Konferensbidrag (refereegranskat)abstract
- Railway traffic disturbances occur and train dispatchers make re-scheduling decisions in order to reduce the delays. In order to support the dispatchers, good rescheduling strategies are required that could reduce the delays. We propose and evaluate re-scheduling strategies based on: (i) earliest start time, (ii) earliest track release time, (iii) smallest buffer time, and (iv) shortest section runtime. A comparative evaluation is done for a busy part of the Swedish railway network. Our results indicate that strategies based on earliest start time and earliest track release time have the best average performance.
|
|
| 31. |
- Öberg, Tomas, et al.
(författare)
-
The chemical and environmental property space of REACH chemicals
- 2012
-
Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 87:8, s. 975-981
-
Tidskriftsartikel (refereegranskat)abstract
- The European regulation on chemicals, REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals), came into force on 1 June 2007. With pre-registration complete in 2008, data for these substances may provide an overview of the expected chemical space and its characteristics. In this paper, using various in silico computation tools, we evaluate 48782 neutral organic compounds from the list to identify hazardous and safe compounds. Two different classification schemes (modified Verhaar and ECOSAR) identified between 17% and 25% of the compounds as expressing only baseline toxicity (narcosis). A smaller portion could be identified as reactive (19%) or specifically acting (2.7%), while the majority were non-assigned (61%). Overall environmental persistence, bioaccumulation and long-range transport potential were evaluated using structure-activity relationships and a multimedia fugacity-based model. A surprisingly high proportion of compounds (20%), mainly aromatic and halogenated, had a very high estimated persistence (> 195 d). The proportion of compounds with a very high estimated bioconcentration or bioaccumulation factor (> 5000) was substantially less (6.9%). Finally, a list was compiled of those compounds within the applicability domain of the models used, meeting both persistence and bioaccumulation criteria, and with a long-range transport potential comparable to PCB. This list of 68 potential persistent organic pollutants contained many well-known compounds (all halogenated), but notably also five fluorinated compounds that were not included in the EINECS inventory. This study demonstrates the usability of in silico tools for identification of potentially environmentally hazardous chemicals.
|
|
| 32. |
- Öberg, Tomas, et al.
(författare)
-
The REACH space of organic chemistry and hazard properties.
- 2011
-
Ingår i: <em>Presentation vid 6th International Symposium on Computational Methods in Toxicology and Pharmacology Integrating Internet Resources (CMTPI-2011) i Maribor, 3-7 september, 2011.</em>.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
