Papers by Mohammad hossein Tahmasebi
Journal of Industrial and Systems Engineering, 2017
One of the most important problems for distribution companies is to find the best locations for d... more One of the most important problems for distribution companies is to find the best locations for depots and to find proper routes for transportation vehicles and to optimize supply network. This study intends to develop a model for the problem of location-routing in post offices. So, a new Bi-Objective Location-Routing Problem for Locating Town Post Office and Routing Parcels is defined. This problem is modeled through mixed-integer mathematical programming. The aim of proposed model is to select potential post offices and to find optimal routes for transportation vehicles while time constraints are taken into account. The proposed model is applied in a real case study including eight main post area and 21 regional offices in Tehran, Iran. A goal programming approach is proposed to solve this bi-objective optimization model. The GAMS Software is used to code and solve the associated mathematical model. Some required parameters of the model such as demands are estimated using Geograph...
J. Web Eng., 2018
It is generally believed that recommender systems are a suitable key to overcome the information ... more It is generally believed that recommender systems are a suitable key to overcome the information overload problem. In recent years, a special research area in this domain has emerged that concerns recommender systems for Technology Enhanced Learning, in particular, self-regulated learning with resources on the web, known as Resource-Based Learning. Grey-sheep users are a major challenge in RecsysTEL. This group of users have completely different opinions from other users. They do not profit from collaborative algorithms, so they must be supported in discovering learning resources relevant to their characteristics and needs. The main contribution of this work is to develop a feature-based educational recommender system which interacts with the user based on his or her learning style. The learning style dimensions would be determined based on Felder-Silverman theory. In addition, the system crawls and extracts the necessary meta-data of sample OCW's web pages. Based on the proposed web page ranking formula, the user's learning style dimension and web page feature's vector would be accommodated to generate learning object suggestions. The general satisfaction, perception and motivation towards the proposed method measured among 77 science and engineering students by a questionnaire. Moreover, the system has been evaluated to provide feedbacks on its suitability. The research findings imply that the proposed method outperforms the general search algorithm. This system can be used as a template in formal and informal learning and educational environments as a RecsysTEL.
Journal of Food Science and Technology, 2019
Nectarines (Prunus persica L. Bath) are very sensitive fruit to fungal infection. Today, the cont... more Nectarines (Prunus persica L. Bath) are very sensitive fruit to fungal infection. Today, the control of postharvest fruit diseases with essential oils (EOs) has been significantly noticed as a novel trend in biological preservation. In this study, volatile compounds of Cinnamon zeylanicum (CEO), Zataria multiflora (ZEO), and Satureja khuzestanica (SEO) were analyzed by Gas Chromatography-Mass spectroscopy. Also, the in vitro antifungal activities of EOs against Botrytis cinerea and Rhizopus stolonifer were evaluated at different concentrations. The in vivo antifungal activity of these EOs on artificially infected nectarine fruits was also considered. The major components were Thymol (32.68%) and Carvacrol (30.57%) for ZEO, cinnamaldehyde (80.82%) for CEO, and carvacrol (38.43%) for SEO. The application of different concentrations showed a decreasing trend in the fungus radial growth in all EOs. In the in vitro experiments, ZEO and CEO exhibited more significant mycelial inhibition results and reduction of the IC 50 , MIC and MFC values against Botrytis cinerea and Rhizopus stolonifer, respectively. However, in the in vitro experiments, none of the treatments were capable of completely inhibiting the growth of the fungi. According to the results of this study, ZEO and CEO could reduce the damage caused by these fungi.
Journal of Advanced Materials In Engineering, 2016
In the present investigation, Mn-Ni binary nano-oxide was deposited by potentiodynamic method on ... more In the present investigation, Mn-Ni binary nano-oxide was deposited by potentiodynamic method on stainless steel at room temperature and the effect of annealing process (at 200 o C for 6 h) on microstructure and electrochemical performance of the synthesized pseudocapacitor was studied. The results showed the significant effect of annealing process on increasing the capacitance and decreasing the charge transfer resistance of the electrode. Field Emission Scanning Electron Miscroscopy (FESEM) images depicted interconnected and random nano-flakes in the oxide film microstructure. Moreover, a partially crystallized structure consisting disorder hexagonal birnessite type phase was formed upon annealing in the deposited oxide film with about 10 %at Ni in composition. Based on the galvanostatic charge-discharge plots, the highest specific capacitance (384 F g-1) and specific energy (53 Wh kg-1) were found at specific current of 0.1 A g-1 for the annealed oxide electrode. Finally, cycle life test results at specific current of 10 A g-1 showed an excellent cyclability and an increase of about 23% in specific capacitance of synthesized pseudocapacitor after 5000 charge-discharge cycles in 1 M Na2SO4.
Electrochimica Acta, 2016
The present study addresses the synthesis of manganese-nickel oxide thin films via potentiodynami... more The present study addresses the synthesis of manganese-nickel oxide thin films via potentiodynamic anodic electrodeposition as supercapacitor electrodes. We study in particular the effect of the deposition scan rate and of the Ni(II) to Mn(II) molar ratio in the deposition bath on the capacitive behaviour of mixed oxide electrodes. The increase of the nickel content in oxide thin films of composition Ni x Mn 1-x O y (with x in the range from 0 to 0.17) results in the increase of specific capacitance up to a maximum for about 10 at% Ni. The deposition scan rate affects the capacitive behaviour of mixed oxide electrodes through its effects on layer morphology and surface structure. In particular, thin film electrodes at about 10 at% Ni show a maximum in the specific capacitance for deposition scan rate of 600 mV s À1 , which is shown to be related to the attendant modifications in surface morphology and topography. After annealing at 200 C, 6 h, partial crystallization of the amorphous structure of the as-grown mixed oxide takes place with formation of dispersed nanocrystalline domains. The annealed electrode at 10 at% Ni, with mass loading of 0.30 mg cm À2 , show the highest specific capacitance (250 F g À1 , at 0.1 A g À1), and specific energy and power as high as 34.5 Wh kg À1 (at 50 W kg À1), and 4.3 kW kg À1 (at 15.7 Wh kg À1). Mixed oxide of the same composition and mass loading reveal a 122% capacitance retention after 10,000 cycles in 1 M Na 2 SO 4 at 20 A g À1 .
Electrochimica Acta, 2016
Manganese-nickel mixed oxide thin films were deposited by anodic electrodeposition on stainless s... more Manganese-nickel mixed oxide thin films were deposited by anodic electrodeposition on stainless steel substrate from an acetate solution using a potentiodynamic technique, at scan rate of 100 mV s-1 and room temperature. The effect of electrolyte pH, varied in the range from 4 to 7, on composition, morphology and capacitance behavior of oxide thin films was investigated. The nickel content in the oxide increased with increasing deposition pH, allowing to investigate the effect of the oxide composition on the capacitive behavior of as-grown manganese-nickel mixed oxides. Oxide films deposited from the electrolyte at pH 6, having a composition close to Ni0.10Mn0.90Ox showed the highest specific capacitance and the lowest charge transfer resistance. After annealing, the oxide had a complex structure of composite nature, consisting of intermixed amorphous and nanocrystalline phases. A birnessite type oxide with turbostratic disorder was identified as the major phase, in the presence of nickel hydroxide as a finely dispersed second phase. Annealing caused a drastic reduction of the charge transfer resistance and a limited increase of the specific capacitance, probably as the result of diverging effects on oxide properties, i.e. enhanced conductivity and porosity sintering. Cycle life testing of this material revealed a 25% increase of the specific capacitance over 5,000 cycles to a final value of 225 F g-1 (1 M Na2SO4, 50 mV s-1 , 0.11 mg cm-2 mass loading).
A Novel Hybrid Structure for Clustering
Communications in Computer and Information Science, 2008
Abstract. Conventional clustering methods such as k-means or subtractive clustering need some inf... more Abstract. Conventional clustering methods such as k-means or subtractive clustering need some information include the optimal number of clusters, oth-erwise, they lead to the poor results. However in many practical situations it is often so difficult to determine the best number of ...
Privacy preservation by k-anonymizing Ngrams of time series
2013 10th International ISC Conference on Information Security and Cryptology (ISCISC), 2013
ABSTRACT Time series data, such as ECG, can be shared publicly for data mining applications and r... more ABSTRACT Time series data, such as ECG, can be shared publicly for data mining applications and researches. This data similar to different kind of data types could be illegally exploited by an adversary to reveal identity of an individual. To prevent re-identification, many k-anonymization methods are introduced. Predictive models use probabilities of Ngrams of time series to predict future values. In this paper we propose an algorithm for k-anonymization of Ngram models of time series. It hides rare Ngrams of the time series between all other Ngrams that their frequencies are guaranteed to be at least k. Utilizing proposed algorithm on the real time series shows its effectivity by maximum information loss 2%.
Journal of The Electrochemical Society, 2018
Attempts to use aluminum-based anodes in lithium-ion batteries often fail due to fast capacity fa... more Attempts to use aluminum-based anodes in lithium-ion batteries often fail due to fast capacity fading. Generally, this has been attributed to pulverization of the electrode and the large volume changes associated with the phase transformation between the crystalline α and β phases of Li-Al alloys. In this study, these transformations were investigated in aluminum films that were lithiated either electrochemically or via direct reaction with lithium metal. Scanning electron microscopy was used to image the samples at different stages of (de)lithiation. By imaging the same locations before and after each step, it can be seen that alloying between Li and Al proceeds from distinct nucleation sites. In situ and ex situ observations reveal that the α-to-β phase transformation is highly anisotropic and causes strong distortions of the film morphology, but only a relatively small amount of mechanical damage such as cracks and delamination. Comparisons between films that were lithiated to 70% and 100% of the theoretical capacity of LiAl indicate that the critical, irreversible damage is more dependent on depth of discharge than on the volume contraction caused by delithiation. Our observations challenge the pessimistic view that pulverization is unavoidable during the phase transformations of the Li-Al system.
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Papers by Mohammad hossein Tahmasebi