با سلام خدمت کاربران در صورتی که با خطای سیستم پرداخت بانکی مواجه شدید از طریق کارت به کارت (6037997535328901 بانک ملی ناصر خنجری ) مقاله خود را دریافت کنید (تا مشکل رفع گردد).
ردیف | عنوان | نوع |
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81 |
A mathematical model for neuronal differentiation in terms of anevolved dynamical system
یک مدل ریاضی برای تمایز عصبی از نظر سیستم دینامیکی برهم خورده-2020 We attempted to create a mathematical model for neuronal differentiation. The present study wasperformed within the framework of self-organization with constraints by looking for an optimized infor-mational unit. We treated networks of individual dynamical system units with an external input, whichwas provided by coupled one-dimensional maps with possible forms of unidirectionally feed-forwardnetwork, random network, small-world network, and fully-connected network. We used a genetic algo-rithm to maximize the information transmission for each type of network. Optimized maps were obtaineddepending on the coupling strength and network structure. These maps can be classified into three types:passive, excitable, and oscillatory. In particular, the excitable and oscillatory types of dynamical systemspossess characteristics that are quite similar to those of neurons, whereas the passive and oscillatorytypes of dynamical system may represent glial cells. Keywords:Self-organization with constraints | Coupled dynamical systems | Evolutionary dynamics | Neuronal differentiation | Oscillology |
مقاله انگلیسی |
82 |
Project schedule performance under general mode implementation disruptions
عملکرد برنامه پروژه تحت اختلال در اجرای کلی حالت-2020 This paper presents a simulation study for a resource-constrained project scheduling problem with mul- tiple alternatives. We decide on a set of baseline schedules at the project planning phase, resulting in options to switch between execution modes of activities during project execution. We assess the perfor- mance of the set of baseline schedules under general mode implementation disruptions. A simple, yet effective algorithm is presented to construct the set of baseline schedules. Moreover, a general disruption system is proposed to model different disruption types, disruption dependencies and disruption sizes. Keywords: Project management | Execution alternatives | Matheuristic | Disruption system |
مقاله انگلیسی |
83 |
Qualitative and quantitative project risk assessment using a hybrid PMBOK model developed under uncertainty conditions
ارزیابی کیفی و کمی ریسک پروژه با استفاده از یک مدل ترکیبی PMBOK که در شرایط عدم اطمینان ایجاد شده است-2020 This study presented a qualitative and quantitative project risk assessment using a hybrid PMBOK model
developed under uncertainty conditions. Accordingly, an exploratory and applied research design was employed
in this study. The research sample included 15 experienced staff working in main and related positions in Neyr
Perse Company. After reviewing the literature and the Project Management Body of Knowledge (PMBOK), 32
risk factors were identified and their number reduced to 17 risks using the expert opinions via the fuzzy Delphi
technique run through three stages. The results of the confirmatory factor analysis showed that all risks were
confirmed by the members of the research sample. Then the identified risks were structured and ranked using
fuzzy DEMATEL and fuzzy ANP techniques. The final results of the study showed that the political and economic
sanctions had the highest weight followed by foreign investors’ attraction and the lack of regional infrastructure.
Keywords: Project risks | Project management body of knowledge(PMBOK) | Uncertainty | Mixed qualitative and quantitative risk | assessment approach | Mathematics | Probability theory | Engineering | Industrial engineering | Business |
مقاله انگلیسی |
84 |
Running power meters and theoretical models based on laws of physics: Effects of environments and running conditions
معیارهای قدرت دویدن و مدلهای نظری مبتنی بر قوانین فیزیک: تأثیر محیط و شرایط دویدن-2020 Training prescription and load monitoring in running activities have benefited from power output (PW) data
offered by new technologies. Nevertheless, to date, the sensitivity of PW data provided by these tools is still not
completely clear. The aim of this study was to analyze the level of agreement between the PW estimated by five
commercial technologies and the two main internationally theoretical models based on laws of physics, in
different environments and running conditions. Ten endurance-trained male athletes performed three submaximal
running protocols on a treadmill (indoor) and an athletic track (outdoor), with changes in speed, body
weight, and slope. PW was simultaneously registered by the commercial technologies Stryd (StrydApp and
StrydWatch), RunScribe, GarminRP and PolarV, whereas theoretical power output (TPW) was calculated by the two
mathematical models (TPW1 and TPW2). Statistics included, among others, the Pearsons correlation coefficient
(r) and standard error of measurement (SEM). The PolarV, and above all Stryd, showed the closest agreement
with the TPW1 (Stryd: r≥0.947, SEM ≤ 11 W; PolarV: r≥0.931, SEM ≤ 64 W) and TPW2 (Stryd: r≥0.933,
SEM ≤ 60 W; PolarV: r≥0.932, SEM ≤ 24 W), both indoors and outdoors. On the other hand, the devices
GarminRP (r≤0.765, SEM ≥ 59 W) and RunScribe. (r≤0.508, SEM ≥ 125 W) showed the lowest agreement
with the TPW1 and TPW2 models for all conditions and environments analyzed. The closest agreement of the
Stryd and PolarV technologies with the TPW1 and TPW2 models suggest these tools as the most sensitive, among
those analyzed, for PW measurement when changing environments and running conditions. Keywords: Endurance | Accelerometer | Variability | Physiology | Biomechanics |
مقاله انگلیسی |
85 |
Optimal energy management for a grid connected PV-battery system
مدیریت بهینه انرژی برای سیستم باتری PV متصل به شبکه-2020 The increase demand for electricity and the non-renewable nature of fossil energy makes the move towards renewable
energies required. However, the common problem of renewable sources, which is the intermittence, is overcome by the
hybridization of complementary sources. Thus, whenever the load demand is not fully covered by the primary source, the
second one will absolutely support it.
Furthermore, the production, the interaction with the grid and the storage system must be managed by the grid-connected
hybrid renewable energy system, which is the main objective of this paper. Indeed, we propose a new system of a grid-connected
PV-battery, which can manage its energy flows via an optimal management algorithm. The DC bus source connection topology
in our proposed hybrid architecture tackles the synchronization issues between sources when the load is powered. We consider
in this work that choosing a battery discharge and charge limiting power provides an extension of the battery life. On the other
hand, we simulated the dynamic behavior of the architecture’s various components according to their mathematical modeling.
Following this, an energy management algorithm was proposed, and simulated using MATLAB/SIMULINK to serve the load.
The results have shown that the load was served in all cases, taking into account the electrical behavior of the inhabitants as
well as the weather changes on a typical day. Indeed, the load was served either by instant solar production between sunrise
and sunset, or the recovery from sunset to 10pm, which could be a stored or injected energy without exceeding the 1000W
per hour Keywords: Renewable energy | PV-battery | Hybrid renewable system | Energy management | Hybrid architecture |
مقاله انگلیسی |
86 |
Research on BP network for retrieving extinction coefficient from Mie scattering signal of lidar
تحقیقات بر روی شبکه BP برای بازیابی ضریب خاموشی از سیگنال پراکندگی میای LIDAR-2020 Mie lidar is a powerful tool for detecting the optical properties of atmospheric aerosols. However, there
are two unknown parameters in the Mie lidar equation: the extinction coefficient and the backscattering
coefficient. In the common methods for solving the equation, it is necessary to make assumptions about
the relationship between the two unknown parameters. These assumptions will reduce the detection
precision of extinction coefficient. In view of this, the back propagation (BP) neural network is used to
retrieve extinction coefficient from the Mie scattering signal of lidar. Firstly, the structure and main
parameters of the BP network are designed according to the practical application. In order to improve
the convergence speed and prevent falling into local minima, the initial weights and thresholds of BP network
are optimized by genetic algorithm (GA). Then the GA-BP network is trained with Mie scattering
signal and the extinction coefficient retrieved by Raman method. Thus the mathematical relationship
between Mie scattering signal and the extinction coefficient is stored in the BP network. The trained
GA-BP network is then used to retrieve the extinction coefficient from Mie scattering signal in different
conditions and the applicability of the GA-BP network is researched. The research will promote the development
of Mie lidar retrieving algorithm. Keywords: Aerosol | Mie scattering | Lidar | Extinction coefficient | BP network | Genetic algorithm |
مقاله انگلیسی |
87 |
Diverse cognitive skills and team performance: A field experiment based on an entrepreneurship education program
Diverse cognitive skills and team performance: A field experiment based on an entrepreneurship education program-2020 Verbal and mathematical reasoning are key cognitive skills which individuals use throughout their lives to create economic value. We argue that individuals undertaking entrepreneurial tasks also draw on these skills, and we study how best these skills should
be combined in entrepreneurial teams. To that purpose we conduct a randomized field
experiment using data from the BizWorld entrepreneurship education program. Four different types of teams are created which differ in terms of their cognitive skill composition.
Our results show that balanced skills are beneficial for a team’s venture performance only
if it comes from within-person skill balance, and that combining team members with different skills in mixed teams does not compensate for a lack of members who individually
possess balanced cognitive skills.
Keywords: Skill balance | Entrepreneurship | Team performance | Team diversity | Field experiment |
مقاله انگلیسی |
88 |
A new stochastic gain adaptive energy management system for smart microgrids considering frequency responsive loads
یک دستاورد تصادفی جدید سیستم مدیریت انرژی تطبیقی برای میکروگریدهای هوشمند با توجه به بارهای پاسخگو فرکانس-2020 Islanded microgrids as flexible, adaptive and sustainable smart cells of distribution power systems
should be operated in accordance to both techno-economic purposes. Motivated by this need, the
microgrid operators are in charge to elevate the active accommodation of both demand-side and
supply-side distributed energy resources. To that end, in this paper, a new flexible frequency dependent
energy management system is proposed through which distributed generators have time varying
droop controllers with a gain-adaptive strategy. Besides to cope economically with uncertainty arise
frequency excursions, a new, comfort-aware and versatile frequency dependent demand response
program is mathematically formulated and conducted to the energy management system. It is aimed to
co-optimize the microgrid energy resources such a way the day-ahead operational costs are managed
subject to a secure frequency control portfolio. The presented model is solved using a two-stage
stochastic programming and by a tractable efficient mixed integer linear programming approach. The
simulation results are derived in 24-h scheduling time horizon and implemented on a typical test
microgrid. The effectiveness of the proposed hourly gain assignment and frequency responsive load
management program has been verified thoroughly by analyzing the results. Keywords: Hierarchical control structure | Islanded microgrids | Droop gain scheduling | Frequency responsive loads | Two-stage stochastic optimization |
مقاله انگلیسی |
89 |
Structural models based on 3D constitutive laws: Variational structure and numerical solution
مدل های ساختاری مبتنی بر قوانین سازنده سه بعدی: ساختار تغییرات و راه حل عددی-2020 In all structural models, the section or fiber response is a relation between the strain measures and the stress resultants. This
relation can only be expressed in a simple analytical form when the material response is linear elastic. For other, more complex
and interesting situations, kinematic and kinetic hypotheses need to be invoked, and a constrained three-dimensional constitutive
relation has to be employed at every point of the section in order to implement non-linear and dissipative constitutive laws
into dimensionally reduced structural models. In this article we explain in which sense reduced constitutive models can be
expressed as minimization problems, helping to formulate the global equilibrium as a single optimization problem. Casting
the problem this way has implications from the mathematical and numerical points of view, naturally defining error indicators.
General purpose solution algorithms for constrained material response, with and without optimization character, are discussed
and provided in an open-source library. Keywords: Structural models | Constitutive models | Variational method | Error estimation |
مقاله انگلیسی |
90 |
Exploring the role of the sharing economy in disasters management
بررسی نقش اقتصاد مشترک در مدیریت بلایا-2020 Improvements in information and communications technologies (ICTs) have facilitated the inclusion of the sharing economy (SE) in societies more than ever. In the aftermath of recent disasters, the SE played significant roles to help the affected people and support official responders. However, the literature has not effectively explored these roles, and thus, no framework can support the systematic inclusion of the SE in disasters management. This paper aims to address the gap through a two-stage exploratory research approach. First, we conduct a systematic literature review to identify the extent to which the SE is taken into consideration in disasters. After that, we investigate the role of three Iranian SE-based companies that were involved in the 2019 Iran floods response. We collect empirical data by conducting semi-structured interviews and reviewing official reports. Our findings indicate that very few studies discuss the different roles of the SE in disasters, although SE companies have often provided effective solutions to address critical post-disaster logistics challenges. Four research propositions are presented to describe emerging roles for SE companies. The contribution of our study is twofold. First, our research identifies the different roles that the SE could play in disasters and therefore, brings a new perspective to the literature. Second, the study suggests opportunities for collaboration and partnership models from the point of origin to delivery that can support coordination and logistics in disasters. Keywords: Sharing economy | Disaster management | Cross-sector collaboration | The 2019 Iran floods |
مقاله انگلیسی |