Alireza Jalali | University of Ottawa | Université d'Ottawa (original) (raw)

Papers by Alireza Jalali

Computational and Mathematical Methods in Medicine, 2018

Introduction. The quality of cardiopulmonary resuscitation (CPR) has been shown to impact patient... more Introduction. The quality of cardiopulmonary resuscitation (CPR) has been shown to impact patient outcomes. However, post-CPR morbidity and mortality remain high, and CPR optimization is an area of active research. One approach to optimizing CPR involves establishing reliable CPR performance measures and then modifying CPR parameters, such as compressions and ventilator breaths, to enhance these measures. We aimed to define a reliable CPR performance measure, optimize the CPR performance based on the defined measure and design a dynamically optimized scheme that varies CPR parameters to optimize CPR performance. Materials and Methods. We selected total blood gas delivery (systemic oxygen delivery and carbon dioxide delivery to the lungs) as an objective function for maximization. CPR parameters were divided into three categories: rescuer dependent, patient dependent, and constant parameters. Two optimization schemes were developed using simulated annealing method: a global optimizat...

The first step in improving the cardiopulmonary resuscitation (CPR) procedure is to understand ho... more The first step in improving the cardiopulmonary resuscitation (CPR) procedure is to understand how the force applied on the chest relates to the resulting blood pressure. In order to capture the mechanical properties of the chest and abdomen accurately, in this paper we proposed a nonlinear mass spring and damper model which consists of nonlinear spring up to 5th order, a combination of viscous and hysteresis damper. We then nondimensionalized the proposed model in order to enhance parametric study of the model for future use. In the next step we used gradient decent optimization method to identify the model parameters for force-compression data of 10273 CPR cycles collected from different pigs at the Children's Hospital of Philadelphia (CHOP). We used the mean square error (RMSE) between the estimated force and actual force for each cycle as an objective function to be minimized. Using the above method we were able to estimate the model parameters for each cycle seperately. In order to find a best set of estimated parameters we used K-nearest neighbor (K-NN) method. K-NN is an unsupervised learning technique which clusters the data into different groups based on the distance metric. The cluster center with lowest RMSE is selected as the estimated parameters for the entire cycles. The resulted MSE of testing entire cycles with the estimated parameters are 0.12 mean and 0.04 SD. Results show that the proposed model is the most accurate model of pig chest during the CPR.

Applied and Computational Mechanics, 2019

In the current study, non-Newtonian flow pattern and heat transfer in an enclosure containing a t... more In the current study, non-Newtonian flow pattern and heat transfer in an enclosure containing a tilted square are examined. In order to numerically simulate the problem, the mesoscopic lattice Boltzmann method is utilized. The non-Newtonian Carreau-Yasuda model is employed. It is able to adequately handle the shear-thinning case. The simulation results of flow and heat transfer have been successfully verified with the previous studies. Several parameters such as Nusselt number, Drag coefficient, and Carreau number are investigated in details. Considering the temperature-dependent viscosity, it is seen that with increasing thetemperature-thinning index, the drag coefficient increases, but the Nusselt number decreases. By rotating the square obstacle, the results display that increasing the angle of inclination from zero to 45 degrees, increases both the drag coefficient and the Nusselt number. Also, the highest rate of heat transfer occur at the angle of 45 degrees (diamond); however...

Physical Review D, 2017

We use the compatibility of D-brane action with linear off-shell T-duality and linear on-shell S-... more We use the compatibility of D-brane action with linear off-shell T-duality and linear on-shell S-duality as guiding principles to find all world volume couplings of one massless closed and three massless open strings at order α ′2 in type II superstring theories in flat space-time.

Lecture Notes in Computer Science, 2013

Physical Review D, 2015

We use compatibility of D-brane action with linear T-duality, S-duality and with Smatrix elements... more We use compatibility of D-brane action with linear T-duality, S-duality and with Smatrix elements as guiding principles to find all world volume couplings of one massless closed and two open strings at order α ′2 in type II superstring theories. In particular, we find that the squares of second fundamental form appear only in world volume curvatures, and confirm the observation that dilaton appears in string frame action via the transformationR µν →R µν + ∇ µ ∇ ν Φ.

Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2013

Proceedings of the Web Conference 2021, 2021

When receiving machine learning services from the cloud, the provider does not need to receive al... more When receiving machine learning services from the cloud, the provider does not need to receive all features; in fact, only a subset of the features are necessary for the target prediction task. Discerning this subset is the key problem of this work. We formulate this problem as a gradient-based perturbation maximization method that discovers this subset in the input feature space with respect to the functionality of the prediction model used by the provider. After identifying the subset, our framework, Cloak, suppresses the rest of the features using utility-preserving constant values that are discovered through a separate gradient-based optimization process. We show that Cloak does not necessarily require collaboration from the service provider beyond its normal service, and can be applied in scenarios where we only have black-box access to the service provider's model. We theoretically guarantee that Cloak's optimizations reduce the upper bound of the Mutual Information (MI) between the data and the sifted representations that are sent out. Experimental results show that Cloak reduces the mutual information between the input and the sifted representations by 85.01% with only negligible reduction in utility (1.42%). In addition, we show that Cloak greatly diminishes adversaries' ability to learn and infer non-conducive features. CCS CONCEPTS • Security and privacy → Privacy protections; Usability in security and privacy; • Computing methodologies → Neural networks; Computer vision tasks; • Mathematics of computing → Information theory.

Proceedings of the Twenty-Fifth International Conference on Architectural Support for Programming Languages and Operating Systems, 2020

A wide variety of deep neural applications increasingly rely on the cloud to perform their comput... more A wide variety of deep neural applications increasingly rely on the cloud to perform their compute-heavy inference. This common practice requires sending private and privileged data over the network to remote servers, exposing it to the service provider and potentially compromising its privacy. Even if the provider is trusted, the data can still be vulnerable over communication channels or via side-channel attacks in the cloud. To that end, this paper aims to reduce the information content of the communicated data with as little as possible compromise on the inference accuracy by making the sent data noisy. An undisciplined addition of noise can significantly reduce the accuracy of inference, rendering the service unusable. To address this challenge, this paper devises Shredder, an end-to-end framework, that, without altering the topology or the weights of a pre-trained network, learns additive noise distributions that significantly reduce the information content of communicated data while maintaining the inference accuracy. The key idea is finding the additive noise distributions by casting it as a disjoint offline learning process with a loss function that strikes a balance between accuracy and information degradation. The loss function also exposes a knob for a disciplined and controlled asymmetric trade-off between privacy and accuracy. While keeping the DNN intact, Shredder divides inference between the cloud and the edge device, striking a balance between computation and communication. In the separate phase of inference, the edge device takes samples from the Laplace distributions that were collected during the proposed offline learning phase and populates a noise tensor with these sampled elements. Then, the edge device merely adds this populated noise tensor to the intermediate results to be sent to the cloud. As such, Shredder enables accurate inference on

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BioMed research international, 2015

This paper is concerned with the mathematical modeling of a severe and common congenital defect c... more This paper is concerned with the mathematical modeling of a severe and common congenital defect called hypoplastic left heart syndrome (HLHS). Surgical approaches are utilized for palliating this heart condition; however, a brain white matter injury called periventricular leukomalacia (PVL) occurs with high prevalence at or around the time of surgery, the exact cause of which is not known presently. Our main goal in this paper is to study the hemodynamic conditions under which HLHS physiology may lead to the occurrence of PVL. A lumped parameter model of the HLHS circulation has been developed integrating diffusion modeling of oxygen and carbon dioxide concentrations in order to study hemodynamic variables such as pressure, flow, and blood gas concentration. Results presented include calculations of blood pressures and flow rates in different parts of the circulation. Simulations also show changes in the ratio of pulmonary to systemic blood flow rates when the sizes of the patent du...

American Journal of Physical Medicine & Rehabilitation, 2015

In a cross-sectional, multistage sampling method, patients with clinical, electromyographic, and ... more In a cross-sectional, multistage sampling method, patients with clinical, electromyographic, and magnetic resonance imaging findings consistent with lumbosacral radiculopathy were examined for the presence of gluteal trigger point. Age-and sex-matched clusters of healthy volunteers were selected as the control group. The primary outcome of the study was the presence or absence of gluteal trigger point in the gluteal region of the patients and the control group. Results: Of 441 screened patients, 271 met all the inclusion criteria for lumbosacral radiculopathy and were included in the study. Gluteal trigger point was identified in 207 (76.4%) of the 271 patients with radiculopathy, compared with 3 (1.9%) of 152 healthy volunteers (P G 0.001). The location of gluteal trigger point matched the side of painful radiculopathy in 74.6% of patients with a unilateral radicular pain. There was a significant correlation between the side of the gluteal trigger point and the side of patients' radicular pain (P G 0.001). Conclusions: Although rare in the healthy volunteers, most of the patients with lumbosacral radiculopathy had gluteal trigger point, located at the painful side. Further studies are required to test the hypothesis that specific gluteal trigger point therapy could be beneficial in these patients.

Acta medica Iranica, 2012

Cyclophosphamide (CP) is extensively used as an antineoplastic agent for the treatment of various... more Cyclophosphamide (CP) is extensively used as an antineoplastic agent for the treatment of various cancers, as well as an immunosuppressive agent. However, despite its wide spectrum of clinical uses, CP is known to cause several adverse effects including reproductive toxicity. Crataegus monogyna is one of the oldest pharmaceutical plants that have been shown to be cytoprotective by scavenging free radicals. The present study was conducted to assess whether Crataegus monogyna fruits aqueous extract with anti-oxidant properties, could serve as a protective agent against reproductive toxicity during CP treatment in a rat model. Male Wistar rats were categorized into four groups. Two groups of rats were administered CP at a dose of 5 mg in 5 ml saline/kg/day for 28 days by oral gavages. One of these groups received Crataegus monogyna aqueous extract at a dose of 20 mg/kg/day orally four hours after cyclophosphamide administration. A vehicle treated control group and a Crataegus monogyna ...

Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2012

This paper is concerned with the prediction of the occurrence of periventricular leukomalacia (PV... more This paper is concerned with the prediction of the occurrence of periventricular leukomalacia (PVL) that occurs in neonates after heart surgery. The data which is collected over a period of 12 hours after cardiac surgery contains vital measurements as well as blood gas measurements with different resolutions. Vital data measured using near-inferred spectroscopy (NIRS) at the sampling rate of 0.25 Hz and blood gas measurement up to 12 times with irregular time intervals for 35 patients collected at Children's Hospital of Philadelphia (CHOP) are used for this study. Features derived from the data include statistical moments (mean, variance, skewness and kurtosis), trend and minimum and maximum values of the vital data and rate of change, time weighted mean and a custom defined out of range index (ORI) for the blood gas data. A decision tree is developed for the vital data in order to identify the most important vital measurements. In addition, a decision tree is developed for bloo...

IEEE Journal of Biomedical and Health Informatics, 2014

This paper is concerned with predicting the occurrence of Periventricular Leukomalacia (PVL) usin... more This paper is concerned with predicting the occurrence of Periventricular Leukomalacia (PVL) using vital and blood gas data which are collected over a period of twelve hours after neonatal cardiac surgery. A data mining approach has been employed to generate a set of rules for classification of subjects as healthy or PVL affected. In view of the fact that blood gas and vital data have different sampling rates, in this study we have divided the data into two categories: (i) high resolution (vital), and (ii) low resolution (blood gas), and designed a separate classifier based on each data category. The developed algorithm is composed of several stages; first, a feature pool has been extracted from each data category and the extracted features have been ranked based on the data reliability and their mutual information content with the output. An optimal feature subset with the highest discriminative capability has been formed using simultaneous maximization of the class separability measure and mutual information of a set. Two separate decision trees (DT) have been developed for the classification purpose and more importantly to discover hidden relationships that exist among the data to help us better understand PVL pathophysiology. The DT result shows that high amplitude twenty minute variations and low sample entropy in the vital data and the defined out of range index as well as maximum rate of change in blood gas data are important factors for PVL prediction. Low sample entropy represents lack of variability in

Procedia Computer Science, 2011

The significant impact of e-commerce (EC) on the livelihood or rural populations in developing co... more The significant impact of e-commerce (EC) on the livelihood or rural populations in developing countries like Iran has made this topic of popular interest to many researchers in the past decade. To take advantage of e-commerce, employing suitable models which are adaptive to the circumstances of villages in rural areas is indispensable. Iran is on track for achieving this goal, development of EC in Rural areas. Considering the importance of sharing rural ICT experiences, the trend and experiences of the Rural EC infrastructure in Iran are demonstrated in this paper. According to our research, Iran's rural ICT network development started in 2000 with the far northern village of Shahkooh which is known as the first multi-media center of Iran. In 2004, Iran national strategic plan of Rural ICT built two well-equipped telecentres near the villages of East Livan and Gharnabad. Taking availability of data and the duration of operational time to account, these two telecenters were selected for this paper. In 2005, UNESCO Tehran Cluster Office was empowered to carry out a study on the economic and social effect of rural ICTs to share with others, acting in this field at regional and social levels. In fact, in order to find applicable and durable solutions for economic, social and environmental problems, these projects were carried out in the rural areas of Iran. In this paper, a practical model of e-commerce for rural areas of Iran is proposed. Our research is based on quantitative and qualitative methodologies. The qualitative methods comprised of open-ended interviews with officials and telecentre operators. The proposed model is related to the national project known as "10000 Rural ICT Center" which was started in the year 2004. In this project, Rural EC services are part of the IT application services at the Rural ICT Centers which supply four services; Communication Services, IT services, Postal Services and E-Banking services.

Pain Medicine, 2012

Objective. The aim of this study was to assess validity, reliability, and sensitivity of the Pers... more Objective. The aim of this study was to assess validity, reliability, and sensitivity of the Persian version of the short-form McGill Pain Questionnaire 2 (SF-MPQ-2) in patients with neuropathic and nonneuropathic pain. Design. Beaton's guideline was used to translate and adapt the SF-MPQ-2 to Persian. Subjects. One hundred eighty-four patients with subacute and chronic non-neuropathic pain and 74 patients with painful diabetic peripheral neuropathy (total 258) attending multidisciplinary pain clinic participated in the study. Outcome Measures. Internal consistency and intraclass correlation coefficient (ICC) were estimated for participants who had completed the questionnaire in the morning and evening of the first day. The visual analog scale (VAS) and the present pain intensity (PPI) were also recorded to test convergent validity of the questionnaire. Sensitivity to change was examined after a standard treatment and validated by means of the patient global impression of change (PGIC) in addition to VAS and PPI. Exploratory factor analysis (EFA) was used to find possible components. Results. Cronbach's alpha was 0.906, which showed high internal consistency. ICC (0.941) revealed test-retest reliability. There was high correlation between the mean VAS and the mean total score (r = 0.926). Patients in different levels of PPI and PGIC exhibited significant differences among their mean total scores (P < 0.05). EFA revealed four components similar to the original SF-MPQ-2. Conclusion. The Persian translation of the expanded and revised version of the SF-MPQ-2 is a highly reliable, sensitive, and valid instrument to evaluate pain in patients with and without neuropathic etiology.

This paper is focused on the identification of the heart rate (HR) baroreflex mechanism using new... more This paper is focused on the identification of the heart rate (HR) baroreflex mechanism using new nonlinear system identification approach. The proposed HR baroreflex model is based on inherent features of the autonomic nervous system for which we develop an adaptive neuro-fuzzy inference system (ANFIS) structure. The simulation results show significant improvements in prediction of HR as a model output by calculating the normalized root mean square error (NRMSE) in comparison with other reported methods. We have shown that for modeling of cardiovascular system regulation, our proposed nonlinear model is more accurate than other recently developed methods.