Metaheuristic for Solving the Delivery Man Problem with Drone

Delivery Man Problem with Drone (DMPD) is a variant of Delivery Man Problem (DMP). The objective of DMP is to minimize the sum of customers' waiting times. In DMP, there is only a truck to deliver materials to customers while the delivery is completed by collaboration between truck and drone in DMPD. Using a drone is useful when a truck cannot reach some customers in particular circumstances such as narrow roads or natural disasters. For NP-hard problems, metaheuristic is a natural approach to solve medium to large-sized instances. In this paper, a metaheuristic algorithm is proposed. Initially, a solution without drone is created. Then, it is an input of split procedure to convert DMP-solution into DMPD-solution. After that, it is improved by the combination of Variable Neighborhood Search (VNS) and Tabu Search (TS). To explore a new solution space, diversification is applied. The proposed algorithm balances diversification and intensification to prevent the search from local optima. The experimental simulations show that the proposed algorithm reaches good solutions fast, even for large instances

Hybrid Variable Neighborhood Search for Solving School Bus-Driver Problem with Resource Constraints

The School Bus-Driver Problem with Resource Constraints (SBDP-RC) is an optimization problem with many practical applications. In the problem, the number of vehicles is prepared to pick a number of pupils, in which the total resource of all vehicles is less than a predefined value. The aim is to find a tour minimizing the sum of pupils’ waiting times. The problem is NP-hard in the general case. In many cases, reaching a feasible solution becomes an NP-hard problem. To solve the large-sized problem, a metaheuristic approach is a suitable approach. The first phase creates an initial solution by the construction heuristic based on Insertion Heuristic. After that, the post phase improves the solution by the General Variable Neighborhood Search (GVNS) with Random Neighborhood Search combined with Shaking Technique. The hybridization ensures the balance between exploitation and exploration. Therefore, the proposed algorithm can escape from local optimal solutions. The proposed metaheuristic algorithm is tested on a benchmark to show the efficiency of the algorithm. The results show that the algorithm receives good feasible solutions fast. Additionally, in many cases, better solutions can be found in comparison with the previous metaheuristic algorithms

FIELD TEST ON CLEANING OF OIL POLLUTION ON NHATRANG BEACH OF VIETNAM

Joint Research on Environmental Science and Technology for the Eart

A SOCIAL SURVEY ON COMMUNITY RESPONSE TO ROAD TRAFFIC NOISE IN HANOI

Joint Research on Environmental Science and Technology for the Eart

EVALUATION OF THE VULNERABILITY OF THE COASTAL SOCIO-NATURAL SYSTEMS (EXAMPLE FROM KHANH HOA COASTAL ZONE)

Joint Research on Environmental Science and Technology for the Eart

Effect of deposition time on gold nanodendrite porous structure and on signals of Hg(II) in environment

The influences of deposition time (tdep) for Au nanodendrite preparation on carbon cloth electrodes on the surface structure, electrochemical behavior and voltammetric signal for Hg(II) detection have been studied. The obtained results showed that from 60 s to 300 s, the longer deposition time, the larger dendrite length as well as the more increased density of dendrite structure became. Calculated from data showed that the electroactive surface area approached to the maximum value of 3.686 cm2 with tdep = 300 s. The typical electrochemical behaviour of the prepared electrodes was mass transfer diffusion to the electrode surface and being considered as planar diffusion. Using DPASV technique, the peak height of Hg(II) could appoach to 52 µA with tdep = 60 s. Keywords. Gold nanodendrite, deposition time, surface structure, electrochemical properties, mercury

Impact of Vocational Education and Training On Decent Job Opportunities Regarding Information and Communication Technology

Vocational education and training plays a crucial part in the creation of decent job. The fast growth of information and communication technology (ICT) during the past ten years has increased work opportunities for laborers. This research uses the yearly labor force survey data to study the impact of vocational education and training on decent job opportunities for employees in the context of Vietnam's information and communication technology development. The logit model results indicate that the 2020 rate of decent jobs is still low, at approximately 25.6 percent. However, vocational education and training and the advancement of ICT positively affect decent job opportunities. This long-lasting impact affects laborers in various areas, regions, and industries. These findings suggest that vocational education and training and ICT must play a significant role in transitioning from precarious to more secure employment, so laborers must acquire professional knowledge and information technology skills

A Giant Frontal Meningioma with Psychiatric Symptoms in a Young Woman: A Case Report

Background:Frontal meningioma is often asymptomatic but patients might experience psychiatric symptoms. Since symptoms are atypical in giant meningioma, to the best of our knowledge, we present a rare clinical scenario. Case Presentation: A 24-year old female patient with no medical history presented with two months of depressive symptoms, personality changes such as easy irritability, and feelings of frustration and mental depression, as well as forgetfulness and blurred vision. Brain magnetic resonance imaging (MRI) revealed a well-defined markedly enhancing lesion in the left frontal region measuring 65 x 70 x 70 mm with mass effects to the adjacent brain tissue and associated surrounding edema which was pressed to the frontal horn of the lateral ventricle. The patient underwent frontal unilateral craniotomy and excision of the tumor. After surgery, the quality of life was improved. Conclusion: Meningioma with psychiatric symptoms is quite rare. This clinical case helps clinicians avoid missing symptoms and use appropriate management strategies for patients with giant meningiomas