An investigation of heuristic decomposition to tackle workforce scheduling and routing with time-dependent activities constraints

This paper presents an investigation into the application of heuristic decomposition and mixed-integer programming to tackle workforce scheduling and routing problems (WSRP) that involve timedependent activities constraints. These constraints refer to time-wise dependencies between activities. The decomposition method investigated here is called repeated decomposition with con ict repair (RDCR) and it consists of repeatedly applying a phase of problem decomposition and sub-problem solving, followed by a phase dedicated to con ict repair. In order to deal with the time-dependent activities constraints, the problem decomposition puts all activities associated to the same location and their dependent activities in the same sub-problem. This is to guarantee the satisfaction of time-dependent activities constraints as each sub-problem is solved exactly with an exact solver. Once the assignments are made, the time windows of dependent activities are fixed even if those activities are subject to the repair phase. The paper presents an experimental study to assess the performance of the decomposition method when compared to a tailored greedy heuristic. Results show that the proposed RDCR is an effective approach to harness the power of mixed integer programming solvers to tackle the diffcult and highly constrained WSRP in practical computational time. Also, an analysis is conducted in order to understand how the performance of the different solution methods (the decomposition, the tailored heuristic and the MIP solver) is accected by the size of the problem instances and other features of the problem. The paper concludes by making some recommendations on the type of method that could be more suitable for different problem sizes

Rate and causes of lost "gillnets and entangling nets" in the black sea coasts of turkey

In this study, we determined the numbers of gillnets and entangling nets used throughout the Black Sea coasts of Turkey. In addition the number of nets lost over a one year period and principal causes of loss were also calculated. Field studies were carried out at 158 fishing ports in 15 provinces between February 2015 and December 2016. All nets from 3372 fishing boats were counted to determine the total number of gillnets and entangling nets. In order to determine numbers of lost nets, we conducted personal interviews with the skippers of 315 randomly selected fishing boats. Gillnets and entangling nets in the region were divided into 5 categories (Turbot, Whiting, Bonito, Red mullet and Other sp. net) according to target species. Calculations revealed the total number of net panels as 107331 panels. The total number of Turbot, Whiting, Bonito, Red mullet nets and Other sp. net panels were found to be 47144 (43.92%), 22919 (21.35%), 17366 (16.18%), 10461 (9.75%) and 9441 (8.80%) respectively. The average amounts of nets lost per fishing boat were estimated as 2.22±0.74, 1.54±0.47, 0.83±0.43, 1.57±0.57 and 1.56±0.11 panels respectively. The total amount of panels lost throughout the Black Sea was determined as 1626.83 (1.52%) panels/year. © 2018, Central Fisheries Research Inst. All rights reserved.This study was funded by the General Directorate of Agricultural Research and Policies. The data were collected within the framework of TAGEM /HAYSUD/2015/A11/P-09/02?“Investigation?of?Gillnets? and Effects in Black Sea Fisheries" project. The authors are grateful to the anonymous referee for their valuable input on an earlier version of the article and to Alison Kideyş?for?her?linguistic?corrections. Also, we thank Serdar?Sakınan?for?his?contribution

Depression and its Associated Factors among Patients Attending Chronic Disease Clinics in Southwest Trinidad La Depresión y sus Factores Asociados entre los Pacientes que Asisten a las Clínicas de Enfermedades Crónicas en el Suroeste de Trinidad

ABSTRAC

Sudden bilateral hearing loss in gastric cancer as the only symptom of disease

Zoran Rakusic,1 Ana Misir Krpan,1 Darija Stupin Polancec,2 Antonia Jakovcevic,3 Vesna Bisof1 1Department of Oncology, University Hospital Center Zagreb, 2Fidelta Ltd for Research and Development, 3Department of Pathology, University Hospital Center Zagreb, Zagreb, Croatia Abstract: This paper reports a case of sudden bilateral deafness as the first symptom of gastric cancer, an extremely rare and atypical clinical situation. Because common signs of stomach cancer were absent, the patient was first evaluated in the Department of Otolaryngology, University Hospital Center, Zagreb. Only after expanded diagnostic evaluation and rapid progression of the disease in such a case is a malignant tumor suspected. Treatment is mostly ineffective. The unusual presentation of the disease and the rapid course may indicate a hereditary predisposition. Inactivation of tumor suppressor gene DFNA5 was found in 50% of gastric cancers, but of a non-metastasized phenotype. Inactivated DFNA5, otherwise described in hereditary bilateral deafness, perhaps favors the development of deafness in patients with gastric cancer. Our patient had a positive multiple viral antibody titer in serum, inactivated DFNA5 in both gastric cancer tissues and cerebellar metastases, and a metastatic form of the disease. If sudden deafness occurs in elderly patients, the possibility of malignant tumor should be taken into consideration. The link between gastric cancer and the DFNA5 gene is unclear and requires further research. Keywords: deafness, gastric cancer, DFNA5 gene, meningeal carcinomatosi