Locating Emergency Facilities Using the Weighted k-median Problem: A Graph-metaheuristic Approach

An efficient approach is presented for addressing the problem of finding the optimal facilities location in conjunction with the k-median method. First the region to be investigated is meshed and an incidence graph is constructed to obtain connectivity properties of meshes. Then shortest route trees (SRTs) are rooted from nodes of the generated graph. Subsequently, in order to divide the nodes of graph or the studied region into optimal k subregions, k-median approach is utilized. The weights of the nodes are considered as the risk factors such as population, seismic and topographic conditions for locating facilities in the high-risk zones to better facilitation. For finding the optimal facility locations, a recently developed meta-heuristic algorithm that is called Colliding Bodies Optimization (CBO) is used. The performance of the proposed method is investigated through different alternatives for minimizing the cost of the weighted k-median problem. As a case study, the Mazandaran province in Iran is considered and the above graph-metaheuristic approach is utilized for locating the facilities

Optimal Design of the Monopole Structures Using the CBO and ECBO Algorithms

Tubular steel monopole structure is widely used for supporting antennas in telecommunication industries. This research presents two recently developed meta-heuristic algorithms, which are called Colliding Bodies Optimization (CBO) and Enhanced Colliding Bodies Optimization (ECBO), for size optimization of monopole steel structures. The design procedure aims to obtain minimum weight of monopole structures subjected to the TIA-EIA222F specification. Two monopole structure examples are examined to verify the suitability of the design procedure and to demonstrate the effectiveness and robustness of the CBO and ECBO in creating optimal design for this problem. The outcomes of the enhanced colliding bodies optimization (ECBO) are also compared to those of the standard colliding bodies optimization (CBO) to illustrate the importance of the enhancement of the CBO algorithm

Optimal Design of Steel Towers Using a Multi-Metaheuristic Based Search Method

In meta-heuristic algorithms, the problem of parameter tuning is one of the most important issues that can be highly time consuming. To overcome this difficulty, a number of researchers have improved the performance of their methods by enhancement and hybridization with other algorithms. In the present paper efforts are made to search design space simultaneously by the Multi Metaheuristic based Search Method (MMSM). In the proposed method, optimization process is performed by dividing the initial population into five subsets so-called islands. An improved multi-metaheuristic method is then employed. After a certain number of repetitions (migration intervals), some percent of the island’s best members are transferred into another island (migration) and replaced by the members of low fitnesses. In the migration phase, the target island is chosen randomly. Examples of large design spaces are utilized to investigate the efficiency of the proposed method. For this purpose, steel are optimized utilizing the proposed method. The results indicate improvements in the available responses

Three dimensional modelling of interaction between surface and Darcy flow regimes through soils

The present paper deals with the impact of surface flow on hydrodynamic conditions in saturated underground domains. A three dimensional finite element scheme has been used to simulate underground flow resulting from the flow of water over a saturated land. The results clearly show the effects of the surface flow on the hydrodynamic conditions of the subsurface porous regions. This analysis is an important prerequisite for the prediction of contaminant mobility in soils and hence provides a convenient tool for the prediction of interaction between surface and subsurface flow processes. For low permeability cases, considered here, the governing equations consist of water continuity and Darcy equations. These equations are solved using a robust and reliable finite element procedure

Determination of tensile behavior of hot-pressed Mg-TiO2 and Mg-ZrO2 nanocomposites using indentation test and a holistic inverse modeling technique

The present study aims to implement a non-destructive approach to determine the tensile properties of magnesium-based nanocomposites reinforced with ZrO2 and TiO2 nanoparticles. Micron-sized magnesium particles were blended with 0, 1.5, 3, and 5 volume percentage of ZrO2 and TiO2 nanoparticles and hot-pressed at 450 °C under the pressure of 600 MPa. Next, the spherical indentation test was performed on the produced composites to obtain the load–penetration curves. A finite element model of the indentation test was then developed using the Hollomon material model with randomly chosen materials constants. At the next stage, load–penetration curves were obtained for each composite using simulations. A Levenberg–Marquardt neural network was then trained and utilized to find the correct material constants by minimizing the differences between the experimental and simulated load–penetration curves. The results indicated that there is a linear relationship between the tensile strength and content of the reinforcement phase, while it is inversely proportional to the size of the reinforcing particles. Magnesium composites reinforced with 5 volume percentage of ZrO2 and TiO2 nanoparticles showed tensile strengths 2.5 and 2.1 times greater than that of unreinforced magnesium, respectively. It was shown that the proposed method is able to calculate the tensile properties of magnesium-based composites in an accurate and inexpensive manner

Clinical Features of Patients Newly Admitted to the Emergency Department of a Psychiatric Hospital with an Emphasis on Physical Examination

Introduction: Many medical diseases and their related signs and symptoms are not identified in routine assessments in emergency departments. Objective: We investigated the prevalence of abnormal findings in physical examination of the patients who were newly admitted to emergency department (ED) of a psychiatric hospital. Methods: We studied 200 patients (143 males, 71.5%) who were recently admitted to the ED of a psychiatric university hospital during a 4-month period in 2018. A thorough physical and neurological examination was performed on each subject. Results: Nearly all of the patients (99.3%) had at least one positive finding in physical (non-neurological) examination and 95% had at least one positive neurological finding. We also found at least one problem in gastrointestinal, respiratory or cardiac system of 22.1%, 24% and 33% of the subjects, respectively. The most frequent findings were in cranial nerve I (30%, more common in substance abuse disorder), and visual acuity (52.6%), as well as recent memory (%68.7), attention (%33.7), orientation to time (%29.5), hypokinetic movements (%28.1, more common in females and psychotic patients), akathisia (41.6%), and skin (%85.1, more common in substance abuse and personality disorders). T wave changes were seen in 31.9% and arrhythmia in 16% of the patients. Conclusions: Abnormal findings in examination of the patients admitted to EDs are very prevalent, but most of the abnormalities are not detected or reported in the routine ward examinations. More emphasis should be placed on the examination of olfactory nerve (especially in patients with substance abuse disorder), cognition (especially in older adults), extrapyramidal system, heart, abdomen and skin (especially in patients with personality disorder) during the first week of admission in a psychiatric emergency setting

Optimization of multi-product, multi-period closed loop supply chain under uncertainty in product return rate: case study in Kallehdairy company

Abstract Closed Loop production systems attempt to economic improvement, deliver goods to customers with the best quality, decrease in the return rate of expired material and decrease environmental pollution and energy usage. In this study, we solve a multi-product, multi-period closed loop supply chain network in Kalleh dairy company, considering the return rate under uncertainty. The objective of this paper is to develop a supply chain model including raw material suppliers, manufacturers, distributors and a recycle center for returned products. Solving this model helps us to make a good decision about providing materials, production, distribution and recovery. Our basic goal is to estimate optimum return rate of some products such as yoghurt, to production cycle. Once the products pass 3 4 of their shelf life, they are returned to production cycle. For this study, we develop a linear programming model with a consideration of chance constraints. Finally, this model is implemented by Lingo software with using real data. The obtained results by our model show 9.5 % decrease for total cost in comparison with the current status

Impact of gaseous and particulate matter emission for fluid catalytic cracking units

Fluid catalytic cracking unit is a major part of petroleum refineries as it treats heavy fractions from various process units to produce light ends (valuable products). FCC unit feedstock consists of heavy hydrocarbon with high sulphur contents and the catalyst used is zeolite impregnated with rare earth metals i.e. Lanthanum and Cerium. Catalytic cracking reaction takes place at an elevated temperature in fluidized bed reactors generating sulphur-contaminated coke on the catalyst with large quantity of attrited catalyst fines. In the regenerator, coke is completely burnt producing SO2, PM emissions are mainly due to high attrition of cold makeup catalyst charge and operating conditions, vapour velocity particle velocity, particle collision and particle degradation. This study is dedicated to the quantitative analysis of the impact of harmful emissions resulting from FCC units on the environment

Hollow-Core Photonic Crystal Fiber Mach–Zehnder Interferometer for Gas Sensing

A novel and compact interferometric refractive index (RI) point sensor is developed using hollow-core photonic crystal fiber (HC-PCF) and experimentally demonstrated for high sensitivity detection and measurement of pure gases. To construct the device, the sensing element fiber (HC-PCF) was placed between two single-mode fibers with airgaps at each side. Great measurement repeatability was shown in the cyclic test for the detection of various gases. The RI sensitivity of 4629 nm/RIU was demonstrated in the RI range of 1.0000347–1.000436 for the sensor with an HC-PCF length of 3.3 mm. The sensitivity of the proposed Mach–Zehnder interferometer (MZI) sensor increases when the length of the sensing element decreases. It is shown that response and recovery times of the proposed sensor inversely change with the length of HC-PCF. Besides, spatial frequency analysis for a wide range of air-gaps revealed information on the number and power distribution of modes. It is shown that the power is mainly carried by two dominant modes in the proposed structure. The proposed sensors have the potential to improve current technology’s ability to detect and quantify pure gases

Reasons for Discharge against Medical Advice: A Case Study of Emergency Departments in Iran

Background : Incomplete hospitalization is the cause of disease relapse, readmission, and increase in medical costs. Discharge Against Medical Advice (DAMA) in emergency department (ED) is critical for hospitals. This paper aims to explore the underlying reasons behind DAMA in ED of four teaching hospitals in Kerman, Iran. Methods : This was a cross-sectional study in which the samples were drawn from the patients who chose to leave against medical advice from the ED of teaching hospitals in Kerman from February to March 2011. The sampling was based on census. Data were gathered by a self-constructed questionnaire. The reasons for DAMA were divided into three parts: reasons related to patient, medical staff, and hospital environment. The questionnaire was filled out by a face-to-face interview with patient or a reliable companion. Results : There were 121 cases (5.6%) of DAMA out of the total admissions. The main reason of AMA discharges was related to patient factors in 43.9% of cases, while two other factors (i.e., hospital environment and medical staff ) constituded 41.2% and 35.2% of cases, respectively. The majority of patients 65.9% (80 cases) were either uninformed or less informed of the entailing side effects and outcomes of their decision to DAMA. Conclusion : In comparison to studies conducted in other countries, the rate of DAMA is markedly higher in Iran. The results revealed that patients awareness of the consequences of their decisions is evidently inadequate. The study suggests a number of recommendations. These include, increasing patient awareness of the potential side effects of DAMA and creating the necessary culture for this, improving hospital facilities, and a more careful supervision of medical staff performance