scholarly journals Routing two stacking cranes with predetermined container sequences

Author(s):  
Dirk Briskorn

AbstractThe scheduling of gantry cranes with respect to mutual interference has received considerable attention in recent years. We consider a subproblem which arises when each crane has a sequence of tasks to be assigned. The problem is concerned with resolving the interference between two cranes by determining which crane avoids the other in order to let it complete its next task first. We provide a fairly general problem framework accounting for different crane systems and various side constraints. We assume a cost function for each task that determines the cost of completing the task at a specific point in time. We then distinguish between the objectives to minimize both the total cost and the maximum cost among tasks. A general dynamic programming framework is provided which allows us to solve all problem versions in pseudo-polynomial time. Furthermore, we show that while the general problem aiming for minimum total cost is binary NP-hard, the general problem aiming for minimum maximum cost can be solved in polynomial time. Finally, we address two important special cases of the former, and we show that they can be solved in polynomial time as well.

2013 ◽  
Vol 30 (02) ◽  
pp. 1250050 ◽  
Author(s):  
KE FU ◽  
ZHAOWEI MIAO ◽  
JIAYAN XU

A medianoid problem is a competitive location problem that determines the locations of a number of new service facilities that are competing with existing facilities for service to customers. This paper studies the medianoid problem on the plane with Manhattan distance. For the medianoid problem with binary customer preferences, i.e., a case where customers choose the closest facility to satisfy their entire demand, we show that the general problem is NP-hard and present solution methods to solve various special cases in polynomial time. We also show that the problem with partially binary customer preferences can be solved with a similar approach we develop for the model with binary customer preferences.


2020 ◽  
Vol 34 (02) ◽  
pp. 2111-2118
Author(s):  
Minming Li ◽  
Long Tran-Thanh ◽  
Xiaowei Wu

In this paper we consider a defending problem on a network. In the model, the defender holds a total defending resource of R, which can be distributed to the nodes of the network. The defending resource allocated to a node can be shared by its neighbors. There is a weight associated with every edge that represents the efficiency defending resources are shared between neighboring nodes. We consider the setting when each attack can affect not only the target node, but its neighbors as well. Assuming that nodes in the network have different treasures to defend and different defending requirements, the defender aims at allocating the defending resource to the nodes to minimize the loss due to attack. We give polynomial time exact algorithms for two important special cases of the network defending problem. For the case when an attack can only affect the target node, we present an LP-based exact algorithm. For the case when defending resources cannot be shared, we present a max-flow-based exact algorithm. We show that the general problem is NP-hard, and we give a 2-approximation algorithm based on LP-rounding. Moreover, by giving a matching lower bound of 2 on the integrality gap on the LP relaxation, we show that our rounding is tight.


2020 ◽  
Vol 15 ◽  
Author(s):  
Billu Payal ◽  
Anoop Kumar ◽  
Harsh Saxena

Background: Asthma and Chronic Obstructive Pulmonary Diseases (COPD) are well known respiratory diseases affecting millions of peoples in India. In the market, various branded generics, as well as generic drugs, are available for their treatment and how much cost will be saved by utilizing generic medicine is still unclear among physicians. Thus, the main aim of the current investigation was to perform cost-minimization analysis of generic versus branded generic (high and low expensive) drugs and branded generic (high expensive) versus branded generic (least expensive) used in the Department of Pulmonary Medicine of Era Medical University, Lucknow for the treatment of asthma and COPD. Methodology: The current index of medical stores (CIMS) was referred for the cost of branded drugs whereas the cost of generic drugs was taken from Jan Aushadi scheme of India 2016. The percentage of cost variation particularly to Asthma and COPD regimens on substituting available generic drugs was calculated using standard formula and costs were presented in Indian Rupees (as of 2019). Results: The maximum cost variation was found between the respules budesonide high expensive branded generic versus least expensive branded generic drugs and generic versus high expensive branded generic. In combination, the maximum cost variation was observed in the montelukast and levocetirizine combination. Conclusion: In conclusion, this study inferred that substituting generic antiasthmatics and COPD drugs can bring potential cost savings in patients.


1986 ◽  
Vol 9 (3) ◽  
pp. 323-342
Author(s):  
Joseph Y.-T. Leung ◽  
Burkhard Monien

We consider the computational complexity of finding an optimal deadlock recovery. It is known that for an arbitrary number of resource types the problem is NP-hard even when the total cost of deadlocked jobs and the total number of resource units are “small” relative to the number of deadlocked jobs. It is also known that for one resource type the problem is NP-hard when the total cost of deadlocked jobs and the total number of resource units are “large” relative to the number of deadlocked jobs. In this paper we show that for one resource type the problem is solvable in polynomial time when the total cost of deadlocked jobs or the total number of resource units is “small” relative to the number of deadlocked jobs. For fixed m ⩾ 2 resource types, we show that the problem is solvable in polynomial time when the total number of resource units is “small” relative to the number of deadlocked jobs. On the other hand, when the total number of resource units is “large”, the problem becomes NP-hard even when the total cost of deadlocked jobs is “small” relative to the number of deadlocked jobs. The results in the paper, together with previous known ones, give a complete delineation of the complexity of this problem under various assumptions of the input parameters.


2016 ◽  
Vol 07 (01) ◽  
pp. 43-58 ◽  
Author(s):  
Yu Li Huang

SummaryPatient access to care and long wait times has been identified as major problems in outpatient delivery systems. These aspects impact medical staff productivity, service quality, clinic efficiency, and health-care cost.This study proposed to redesign existing patient types into scheduling groups so that the total cost of clinic flow and scheduling flexibility was minimized. The optimal scheduling group aimed to improve clinic efficiency and accessibility.The proposed approach used the simulation optimization technique and was demonstrated in a Primary Care physician clinic. Patient type included, emergency/urgent care (ER/UC), follow-up (FU), new patient (NP), office visit (OV), physical exam (PE), and well child care (WCC). One scheduling group was designed for this physician. The approach steps were to collect physician treatment time data for each patient type, form the possible scheduling groups, simulate daily clinic flow and patient appointment requests, calculate costs of clinic flow as well as appointment flexibility, and find the scheduling group that minimized the total cost.The cost of clinic flow was minimized at the scheduling group of four, an 8.3% reduction from the group of one. The four groups were: 1. WCC, 2. OV, 3. FU and ER/UC, and 4. PE and NP. The cost of flexibility was always minimized at the group of one. The total cost was minimized at the group of two. WCC was considered separate and the others were grouped together. The total cost reduction was 1.3% from the group of one.This study provided an alternative method of redesigning patient scheduling groups to address the impact on both clinic flow and appointment accessibility. Balance between them ensured the feasibility to the recognized issues of patient service and access to care. The robustness of the proposed method on the changes of clinic conditions was also discussed.


Author(s):  
Josu Doncel ◽  
Nicolas Gast ◽  
Bruno Gaujal

We analyze a mean field game model of SIR dynamics (Susceptible, Infected, and Recovered) where players choose when to vaccinate. We show that this game admits a unique mean field equilibrium (MFE) that consists in vaccinating at a maximal rate until a given time and then not vaccinating. The vaccination strategy that minimizes the total cost has the same structure as the MFE. We prove that the vaccination period of the MFE is always smaller than the one minimizing the total cost. This implies that, to encourage optimal vaccination behavior, vaccination should always be subsidized. Finally, we provide numerical experiments to study the convergence of the equilibrium when the system is composed by a finite number of agents ( $N$ ) to the MFE. These experiments show that the convergence rate of the cost is $1/N$ and the convergence of the switching curve is monotone.


2021 ◽  
Vol 7 (1) ◽  
pp. 167-173
Author(s):  
Kelvin Riupassa ◽  
Narizma Nova ◽  
Endah Lestari ◽  
Sri Juniarti Azis ◽  
Wahyu Sulistiadi

Background: An ambulance is a vehicle designed to be able to handle emergency patients, provide first aid and carry out intensive care while on the way to a referral hospital. Ambulance operations require a large amount of funds obtained from APBD funds through tariffs that were passed through the DKI Jakarta Governor Regulation five years ago. For this reason, a new tariff is required to adjust to current conditions. Objectives: The purpose of this study is to calculate the unit cost of ambulance services in DKI Jakarta to be a consideration in the tariff setting policy in DKI Jakarta province. Research Metodes: This study uses a quantitative descriptive approach to obtain information about the unit cost of the Jakarta ambulance production unit. The method used is the calculation of real cost using the basis of the causes of costs. This research was conducted at the DKI Jakarta Emergency Ambulance using secondary data on investment costs, operational costs and maintenance costs in 2018. Results: The total cost of emergency ambulance in 2018 is known that the proportion of three cost components, namely operational costs, is 76%, followed by investment costs of 20% and maintenance costs of 3%. The calculation of the total cost of medical evacuation using the double distribution method is Rp. 98,915,016,805.00 divided by the number of medical evacuations in 2018 of 37,564 activities, the unit cost of medical evacuation for the AGD of DKI Jakarta Health Office is Rp. 2,633,215.00 without subsidies. APBD costs, while if the subsidy component is included in the calculation, the unit cost for one trip to the AGD of the Health Office is Rp. 604,071.00. This is still far above the current tariff of Rp. 450.00, so the cost recovery rate (CRR) is still below. 100%. Conclusion: From the three cost components consisting of investment, operational and maintenance costs,the largest proportion was operational costs at 76%. The Cost Recovery Rate has not reached 100% so that the existing rates have not covered the costs incurred.   Keywords: ambulance; price fixing; unit cost


2019 ◽  
Vol 4 (1) ◽  
pp. 30
Author(s):  
Neno Pratiwi ◽  
Andre Setiawan ◽  
Ilmi Cayono ◽  
Johan Trinanto

ABSTRAK Pada umumnya harga pokok produksi dalam akuntansi diartikan dengan jumlah biaya dari seluruh pemakaian yang telah dilakukan selama proses produksi atau kegiatan yang mana mengubah bahan baku menjadi produk jadi (produk siap pakai/siap saji). Tujuan penting dalam tugas ini yaitu memperhitungkan harga pokok produksi dari UD Mulya Jaya dengan menggunakan pendekatan variabel costing untuk mengetahui besarnya harga pokok pada setiap produk yang diproduksi. Pentingnya penentuan harga pokok produksi dapat dilakukan sebelum para usaha menentukan harga jual. Pendampingan ini bertujuan untuk membantu mencari dan menentukan harga pokok produksi yang dapat digunakan untuk menetapkan harga jual. Pendampingan ini dilakukan untuk membantu wirausaha dalam program kerja, yaitu bimbingan akuntansi dengan fokus perhitungan harga pokok produksi. Dalam menentukan harga pokok produksi pada UD Mulya Jaya dapat menggunakan pendekatan variable costing yang biasanya metode ini digunakan untuk semacam pengambilan keputusan dalam perusahaan. Melalui program pendampingan kewirausahaan didapatkan hasil perhitungan harga pokok produksi yang menggunakan pendekatan variabel costing. Hasil tersebut dapat menjadi suatu keputusan bagi UD Mulya Jaya untuk dapat menetapkan harga pokok produksi pada setiap produk telur asin. Kata Kunci : Kewirausahaan, HPP, Harga.   ABSTRACT In general, the cost of production in accounting is defined as the total cost of all uses that have been made during the production process or activities which convert raw materials into finished products (ready-to-use / ready-to-serve products). An important objective in this task is to calculate the cost of goods manufactured from UD Mulya Jaya by using a variable costing approach to find out the cost of goods on each product produced. The importance of determining the cost of production can be done before businesses determine the selling price. This assistance aims to help find and determine the cost of production that can be used to set the selling price. This assistance is carried out to help entrepreneurs in work programs, namely accounting guidance with a focus on calculating the cost of production. In determining the cost of production at UD Mulya Jaya, it can use the variable costing approach, which is usually used for a kind of decision making in a company. Through the entrepreneurship assistance program, the results of the calculation of the cost of production are obtained using the variable costing approach. These results can be a decision for UD Mulya Jaya to be able to set the cost of production for each salted egg product. Keywords: Entrepreneurship, COGS, Price


2017 ◽  
Vol 24 (5) ◽  
pp. 354 ◽  
Author(s):  
G.N. Honein-AbouHaidar ◽  
J.S. Hoch ◽  
M.J. Dobrow ◽  
T. Stuart-McEwan ◽  
D.R. McCready ◽  
...  

Objectives Diagnostic assessment programs (daps) appear to improve the diagnosis of cancer, but evidence of their cost-effectiveness is lacking. Given that no earlier study used secondary financial data to estimate the cost of diagnostic tests in the province of Ontario, we explored how to use secondary financial data to retrieve the cost of key diagnostic test services in daps, and we tested the reliability of that cost-retrieving method with hospital-reported costs in preparation for future cost-effectiveness studies.Methods We powered our sample at an alpha of 0.05, a power of 80%, and a margin of error of ±5%, and randomly selected a sample of eligible patients referred to a dap for suspected breast cancer during 1 January–31 December 2012. Confirmatory diagnostic tests received by each patient were identified in medical records. Canadian Classification of Health Intervention procedure codes were used to search the secondary financial data Web portal at the Ontario Case Costing Initiative for an estimate of the direct, indirect, and total costs of each test. The hospital-reported cost of each test received was obtained from the host-hospital’s finance department. Descriptive statistics were used to calculate the cost of individual or group confirmatory diagnostic tests, and the Wilcoxon signed-rank test or the paired t-test was used to compare the Ontario Case Costing Initiative and hospital-reported costs.Results For the 191 identified patients with suspected breast cancer, the estimated total cost of $72,195.50 was not significantly different from the hospital-reported total cost of $72,035.52 (p = 0.24). Costs differed significantly when multiple tests to confirm the diagnosis were completed during one patient visit and when confirmatory tests reported in hospital data and in medical records were discrepant. The additional estimated cost for non-salaried physicians delivering diagnostic services was $28,387.50.Conclusions It was feasible to use secondary financial data to retrieve the cost of key diagnostic tests in a breast cancer dap and to compare the reliability of the costs obtained by that estimation method with hospital-reported costs. We identified the strengths and challenges of each approach. Lessons learned from this study have to be taken into consideration in future cost-effectiveness studies.


Author(s):  
Julia Gonzalez ◽  
Diana Carolina Andrade ◽  
JianLi Niu

Abstract Background Acute bacterial skin and skin structure infections (ABSSSIs) are common infectious diseases that cause a significant economic burden on the healthcare system. This study aimed to compare the cost-effectiveness of dalbavancin vs standard of care (SoC) in the treatment of ABSSSI in a community-based healthcare system. Methods This was a retrospective study of adult patients with ABSSSI treated with dalbavancin or SoC during a 27-month period. Patients were matched based on age and body mass index. The primary outcome was average net cost of care to the healthcare system per patient, calculated as the difference between reimbursement payments and the total cost to provide care to the patient. The secondary outcome was proportion of cases successfully treated, defined as no ABSSSI-related readmission within 30 days after the initiation of treatment. Results Of the 418 matched patients, 209 received SoC and 209 received dalbavancin. The average total cost of care per patient was greater with dalbavancin vs SoC ($4770 vs $2709, P < .0001). The average reimbursement per patient was $3084 with dalbavancin vs $2633 SoC (P = .527). The net cost, calculated as revenue minus total cost, was $1685 with dalbavancin vs $75 with SoC (P = .013). The overall treatment success rate was 74% with dalbavancin vs 85% with SoC (P = .004). Conclusions Dalbavancin was more costly than SoC for the treatment of ABSSSI, with a higher 30-day readmission rate. Dalbavancin does not offer an economic or efficacy advantage.


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