Average Operating Cost Research Articles

Day-ahead optimal dispatch method of integrated electric-heat-cool-gas energy system based on N-1 safety criterion

With the continuous development of integrated energy system and the deepening of the coupling relationship between multiple energy flows, the safe and stable operation of the system has received widespread attention. At present, the security of integrated energy system is mostly researched from the perspective of power grid and rarely researched from the perspective of equipment. This study proposes a day-ahead optimal dispatch method of integrated electric-heat-cool-gas energy system based on N-1 safety criterion, which ensures the normal operation of integrated energy system after the failure of a power supply equipment by increasing appropriate amount of power supply. In this study, the changes in equipment power and operating cost before and after equipment failure under the dispatch method considering N-1 safety criterion and the changes in equipment power and operating cost before and after equipment failure under the dispatch method without considering N-1 safety criterion are investigated by numerical simulation. The results show that when a power supply equipment fails, the average daily loss of load is 6139.99 kW for the dispatch method without considering the N-1 safety criterion and the average daily loss of load is 0 kW for the dispatch method considering the N-1 safety criterion. Therefore, the dispatch method considering the N-1 safety criterion performs better in terms of reliability. When a power supply equipment fails, the average operating cost is 5127.71 USD for the dispatch method without considering the N-1 safety criterion and the average operating cost is 4125.56 USD for the dispatch method considering the N-1 safety criterion. Therefore, the dispatch method considering the N-1 safety criterion performs better in terms of economy.

ORGANIZATION OF DELIVERY OF THE COMPANY'S PRODUCTS BY OWN VEHICLES

Purpose. The purpose of the work is the formation and analysis of options for the organization of the delivery of the machine-building enterprise's products by its own vehicles. Methodology. The main stages of choosing a rational technology for the organization of product transportation by own transport based on the developed schedules have been formed. The research was performed on the basis of the analysis of graphs of the dependence of motor vehicle operation indicators on the technology of organizing the transportation of the company's products. Findings. The article develops and analyzes work schedules for the delivery of the company's products by tractor-trailer trucks with semi-trailers. According to the schedules, the duration of delivery of one product in a ready-to-install condition to the consignee, the maximum possible annual volumes of transportation, the maximum and actual average annual operating costs for the delivery of the company's products by its own vehicles are determined. Practical value. The results of the research can be used to make a decision on the expediency of refusing the services of logistics companies to organize the delivery of the company's products to customers.

A simulation-based genetic algorithm for a semi-automated warehouse scheduling problem with processing time variability

For warehouse operations, efficiently scheduling the available resources is crucial to improve the productivity and customer satisfaction. This paper proposes a simulation-based evolutionary algorithm for order scheduling and multi-robot task assignment in a robotic mobile fulfillment system. The algorithm proactively deals with the effects of the processing time variability by evaluating schedules based on both its system performance as well as its robustness under uncertain conditions. The algorithm implements an efficient resource allocation method and a variance reduction technique to reduce the overall computational burden. The experimental results show that the techniques to reduce the computational time are effective and can significantly reduce the amount of simulations required for the fitness evaluation. If a candidate schedule is allocated insufficient simulation replications it can lead to an inaccurate estimate of its long-term average performance. This could lead to an average performance loss of 7.3 %. Furthermore, the proactive scheduler is able to generate schedules that are more robust compared to deterministically generated. A reduction in the average operational cost of about 5 % can be reached, compared to a deterministically generated schedule. The paper reveals the relevance of identifying and modeling uncertainty when designing schedules in an operational system, rather than looking for optimal schedules for ideal scenarios.

Clinical study on the selection of endoscopes and microscopes for transsphenoidal surgery of non-aggressive pituitary macroadenoma and microadenoma and the influencing factors of hyposmia after endoscopic transsphenoidal surgery.

Transsphenoidal surgery, including endoscopic and microscopic resection, is the first choice of treatment for pituitary tumors. With the widespread application of neuroendoscopy in recent decades, there has been a trend to replace microscopes. In clinical practice, we have found that in transsphenoidal surgery for non-invasive microadenomas and macroadenomas, microscopy can achieve a higher total resection rate, shorter operation time, lower incidence of postoperative complications, and faster recovery of olfaction. This study aimed to explore the selection of endoscopes and microscopes for non-aggressive transsphenoidal surgery for pituitary adenomas and the factors affecting olfactory recovery. From August 2019 to October 2022, 93 patients with non-aggressive microadenomas and macroadenomas via the transsphenoidal approach were selected from the First Affiliated Hospital of Harbin Medical University and treated with rich experience in pituitary tumor subspecialty microscopy and endoscopic surgery. Different surgical methods were used to divide the patients into microscopic (n = 35) and endoscopic (n = 58) groups. The total tumor removal rate, intraoperative blood loss, operation time and cost, postoperative hospital stay, recovery of visual function, postoperative changes in hormone levels, complication rate, and recovery from complications 3 months after the operation were compared between the two groups. There were no significant differences in the tumor removal rate, postoperative visual acuity, and visual field recovery between the two groups (p > 0.05). There was a significant difference in the recovery rate of olfactory function between the two groups 3 months after the operation (p < 0.05), and there was no significant difference in the incidence of other complications (p > 0.05); Compared with the two groups, the microscope group had shorter operation time, longer postoperative hospital stay, less average operation cost and less blood loss, and the difference was statistically significant (p < 0.05). The position of the nasal septum mucosal flap incision was a risk factor for hyposmia 3 months after the operation. Microsurgery and endoscopic surgery are suitable surgical treatments for nonaggressive microadenomas and macroadenomas. The total tumor removal and postoperative hormone remission rates of the two surgical methods were approximately the same. However, the microsurgery group had a shorter operation time, less intraoperative blood loss, faster olfactory function recovery, and a lower average operation cost. The position of the nasal septal mucosal flap incision was a risk factor for hyposmia at 3 months postoperatively. Hyposmia is less likely to occur when the superior edge of the nasal septal mucosal flap incision is not higher than the lower edge of the ipsilateral superior turbinate.

Novel data-driven optimal control methods for cost-effective brine treatment

This study presents a novel data-driven optimal control method to minimize the cost of Convection-Enhanced Evaporation (CEE) systems under time-varying weather conditions. CEE is the approach of evaporating water from saline films (brine) on packed evaporation surfaces by air convection. Here, operating variables (brine injection rate, brine temperature, and air speed) are actively controlled as a function of current ambient conditions and daily weather forecast. The controller optimizes the process operation variables based on a dataset consisting of Pareto fronts, obtained in advance by solving a set of optimization problems. Three optimal operation strategies are presented: (1) real-time selection of operating variables, (2) predictive scheduled operation, and (3) hybrid wind-fan operation. The effectiveness of the proposed strategies was assessed through two case studies with distinct geographical locations and weather conditions: Alamogordo, New Mexico, and Minneapolis, Minnesota. The results show significant cost-saving potential relative to static operation. Predictive scheduled operation resulted in an annual average operating costs of $0.91/m3 and $6.63/m3 in Alamogordo and Minneapolis, respectively, with the higher costs in Minneapolis a result of the added thermal energy required to prevent freezing in winter.

Economic rationale for the development of small vertically diversified pork production enterprises in Ukraine

Implementing the vertical diversification strategy for pig-breeding enterprises in Ukraine is one of the factors in increasing their economic efficiency and competitiveness. Mastering the following interrelated links of production and sale in animal husbandry increases enterprises' financial stability and economic security. The article economically substantiates the expediency of capital investments in developing vertically diversified pork production enterprises in Ukraine. The need for investments for the formation of fixed and working capital for the implementation of the project has been determined. The main operating costs for the organization of pig breeding, slaughter, and the sale of meat through the direct sales channel in the amount of 200 tons per year have been calculated. Planning of workforce needs for project implementation has been carried out. The leading indicators of the economic efficiency of capital investments for the production and sale of pork in the newly established enterprise have been determined. According to the study results, the relatively high investment attractiveness of developing small vertically diversified pork production enterprises in Ukraine with an orientation to local markets is substantiated. It has been established that for the implementation of the proposed project, about 1.1 million euros of advanced capital is needed, which is expected to pay off in 3.5 years. The project's five-year net present value has been determined to reach 690,000 euros at a discount rate of 2%. Accordingly, the projected internal rate of return will exceed 26%. The average annual net profit during the project implementation period will be 268 thousand euros, with an average operating cost of 457 thousand euros, allowing us to achieve 65% profitability of production and 32% profitability of pork sales. The projected average net return on capital for the project implementation period is expected to be 35%. The development of vertical diversification in small pork production enterprises in Ukraine will increase the added value and productivity of the involved financial, labor, material, and technical resources.

Evaluation of the efficacy and safety of endoscopic band ligation in the treatment of bleeding from mild to moderate gastric varices type 1.

According to practice guidelines, endoscopic band ligation (EBL) and endoscopic tissue adhesive injection (TAI) are recommended for treating bleeding from esophagogastric varices. However, EBL and TAI are known to cause serious complications, such as hemorrhage from dislodged ligature rings caused by EBL and hemorrhage from operation-related ulcers resulting from TAI. However, the optimal therapy for mild to moderate type 1 gastric variceal hemorrhage (GOV1) has not been determined. Therefore, the aim of this study was to discover an individualized treatment for mild to moderate GOV1. To compare the efficacy, safety and costs of EBL and TAI for the treatment of mild and moderate GOV1. A clinical analysis of the data retrieved from patients with mild or moderate GOV1 gastric varices who were treated under endoscopy was also conducted. Patients were allocated to an EBL group or an endoscopic TAI group. The differences in the incidence of varicose relief, operative time, operation success rate, mortality rate within 6 wk, rebleeding rate, 6-wk operation-related ulcer healing rate, complication rate and average operation cost were compared between the two groups of patients. The total effective rate of the two treatments was similar, but the efficacy of EBL (66.7%) was markedly better than that of TAI (39.2%) (P < 0.05). The operation success rate in both groups was 100%, and the 6-wk mortality rate in both groups was 0%. The average operative time (26 min) in the EBL group was significantly shorter than that in the TAI group (46 min) (P < 0.01). The rate of delayed postoperative rebleeding in the EBL group was significantly lower than that in the TAI group (11.8% vs 45.1%) (P < 0.01). At 6 wk after the operation, the healing rate of operation-related ulcers in the EBL group was 80.4%, which was significantly greater than that in the TAI group (35.3%) (P < 0.01). The incidence of postoperative complications in the two groups was similar. The average cost and other related economic factors were greater for the EBL than for the TAI (P < 0.01). For mild to moderate GOV1, patients with EBL had a greater one-time varix eradication rate, a greater 6-wk operation-related ulcer healing rate, a lower delayed rebleeding rate and a lower cost than patients with TAI.

On Accessibility Fairness in Intermodal Autonomous Mobility-on-Demand Systems

Research on the operation of mobility systems so far has mostly focused on minimizing cost-centered metrics such as average travel time, distance driven, and operational costs. Whilst capturing economic indicators, such metrics do not account for transportation justice aspects. In this paper, we present an optimization model to plan the operation of Intermodal Autonomous Mobility-on-Demand (I-AMoD) systems, where self-driving vehicles provide on-demand mobility jointly with public transit and active modes, with the goal to minimize the accessibility unfairness experienced by the population. Specifically, we first leverage a previously developed network flow model to compute the I-AMoD system operation in a minimum-time manner. Second, we formally define accessibility unfairness, and use it to frame the minimum-accessibility-unfairness problem and cast it as a linear program. We showcase our framework for a real-world case-study in the city of Eindhoven, NL. Our results show that it is possible to reach an operation that is on average fully fair at the cost of a slight travel time increase compared to a minimum-travel-time solution. Thereby we observe that the accessibility fairness of individual paths is, on average, worse than the average values obtained from flows, setting the stage for a discussion on the definition of accessibility fairness itself.

Optimal Design of Rotor Sails Based on Environmental Conditions and Cost

Rotor sails are one of the promising solutions to reducing the energy consumption and CO2 emissions of ships. Previous studies focused on how rotor sails affect ship dynamics and energy consumption. In the present study, an optimization-based workflow was proposed to find the optimal design of a rotor sail based on given environmental conditions for a target ship. Since the performance of a rotor sail depends on both operational conditions and the design of the rotor sail, a two-level optimization problem was proposed to separate the optimization of operational conditions and rotor sail design. At the operational level, the spin ratio of a given rotor sail was optimized at each time step under different environmental conditions. Then, the design of the rotor sail was optimized on the design level considering the initial cost of rotor sails and the average operational cost of the ship depending on the environmental conditions and their probabilities. The reductions in energy consumption of ships having optimal rotor sail designs, considering 5-year, 10-year, 15-year, and 20-year investment plans were found to be 0.34%, 2.7%, 3.91%, and 4.29%, respectively. When more severe environmental conditions were assumed for the 10-year investment plan, the diameter of the rotor sail increased and the reduction in energy consumption increased from 2.7% to 4.06%.

Double-battery configuration method for electric bus operation in cold regions

Managing the energy supply of electric buses (EBs) is critical to balance operational reliability and cost reduction. However, ambient temperature significantly affects energy consumption, posing challenges in providing adequate energy supply, especially in cold regions. In this study, we propose a double-battery configuration approach for EBs operating in cold regions with substantial temperature variations between seasons. The method involves utilizing a higher-capacity battery during winter months and a lower-capacity battery for summer operations. To determine the optimal fleet size, battery capacities, and EB scheduling plans in both winter and summer seasons, we formulate an integer programming model, focusing on minimizing the fleet's average annual operating costs (OC) and carbon emissions (CE). The model is solved using the branch and bound method. A case study is conducted, examining EB routes in 11 cold cities. Results reveal that the double-battery configuration method effectively reduces the fleet's average annual OC and CE. Specifically, the reduction ratio range for OC is from 3.34% to 5.18%, while the reduction ratio for CE ranges from 4.06% to 5.16%.

OTHER-13 A RETROSPECTIVE STUDY OF BRAIN TUMOURS IN YAOUNDE CAMEROON.

Abstract A brain tumour (BT) or intracranial tumour, is an abnormal mass of tissue where cells grow uncontrollably and unaffected by typical cell regulatory systems. In Sub-Saharan Africa, however, these tumours continue to go unnoticed. The aim of this 5-year retrospective study (January 2018 to March 2023), was to determine the relative frequency and histologic types of brain tumours that exist, and to analyze the costs of treatment and diagnostic methods used. The study was conducted within the oncology and neurosurgery departments of 2 Cameroonian hospitals: Yaoundé Central Hospital and Yaoundé General Hospital. A total of 78 complete case files, or 1.05% of all admissions to the various units, were analyzed. The male to female ratio was 0.95 (38M: 40F). 15.4% of cases involved patients below the age of 14. 84.6% involved patients 15years of age and above. 94.9% of the cases were primary brain tumours. In 60.3% of instances, individuals with primary brain tumours were between the ages of 22 and 57. Meningioma (30.8%) was the most common histological form, followed by astrocytoma (25.6%) and pituitary adenomas (16.7%). Most patients experienced symptoms of increased intracranial pressure, with headaches occurring 94.9% of the time. The average diagnostic cost was 235 000 CFA, average operation cost was 337 500 CFA, and average treatment cost was 750 000 CFA, putting the total cost at 1 322 500 CFA. The country's minimum wage is estimated at 40 000CFA (net income), with average household income of 100 000CFA.The age group that is most impacted is young adults, who were more likely to develop meningioma, astrocytoma, and pituitary adenomas than any other types of brain tumours. The total cost of treatment is 33 times the minimum wage or 13 times the average income. To evaluate the long-term outcome of patients with BTs, more research is required.

Financial Analysis of Small Fisherman's Hand Line Fishing Business in Kupang City

The development of the capture fisheries business requires every company and fishery business actor, especially small scale fishermen, to compete and increase the catch from each of their business activities. So that the level of business feasibility is a criterion for investment or long-term investment in a particular production. The purpose of this study was to analyze the handline busines with a vessel size of 2 GT -10 GT in the waters of the city of Kupang. The research method used is a survey method, determining respondents based on purposive sampling. Data collecting done by interview and observation. The data analysis used is descriptive qualitative and quantitative analysis. 30 fishermen who owned handline boats with a size of 2-10 GT were used as the samples. The research was conducted in March - May 2023 at the Tenau Beach Fishing Port (PPP), Kupang city. The business analysis carried out is to look at the average investment costs, fixed costs, operational costs, income and profits of fishing business within 1 year. The results showed that the average investment cost was IDR 161,361,619/year, the total cost was IDR. 354,999,991, -/year total revenue of IDR. 891.066.667.-/year and the ship owner's profit was IDR. 536,066,676,-/year. Based on the results of the analysis, the R/C Ratio and B/C Ratio values are greater than ≥ 1, so it can be concluded that the 2-10 GT small handline fishing vessel business in the waters of Kupang city is profitable and feasible to develop.

Optimal Load-Splitting and Distributed-Caching for Dynamic Content Over the Wireless Edge

In this work, we consider the problem of ‘fresh’ caching at distributed (front-end) local caches of content that is subject to ‘dynamic’ updates at the (back-end) database. We first provide new models and analyses of the average operational cost of a network of distributed edge-caches that utilizes wireless multicast to refresh aging content. We attack the problems of what to cache in each edge-cache and how to split the incoming demand amongst them (also called “load-splitting” in the rest of the paper) in order to minimize the operational cost. While the general form of the problem comes with an NP-hard Knapsack structure, we were able to completely solve the problem by judiciously choosing the number of edge-caches to be deployed over the network This reduces the complex problem to a solvable special case. Interestingly, our findings reveal that the optimal caching policy necessitates unequal load-splitting over the edge-caches even when all conditions are symmetric. Moreover, we find that edge-caches with higher load will generally cache fewer but relatively more popular content. We further investigate the tradeoffs between cost reduction and cache savings when employing equal and optimal load-splitting solutions for demand with Zipf( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$z$</tex-math> </inline-formula> ) popularity distribution. Our analysis reveals that equal load-splitting to edge-caches achieves close-to-optimal for less predictable demand ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$z&lt;2$</tex-math> </inline-formula> ) while also saving in the cache size. On the other hand, for more predictable demand ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$z&gt;2$</tex-math> </inline-formula> ), optimal load-splitting results in substantial cost gains while decreasing the cache occupancy.

Economic Feasibility of Ginger Emprit Extract Drink (Zingiber officinale Var. Amarum) using CMC Stabilizer

The tempe industry is one of the most numerous industries in Indonesia, so there is a high opportunity for making tempeh juice in the tempe industry. The application of tempeh in the manufacture of tempeh essence drink with emprit ginger extract is expected to provide benefits to the tempe industry in Indonesia. Tempe juice drink is one of the processed food products made from tempeh. Tempe juice drink is added with emprit ginger extract to remove the unpleasant aroma from tempeh and give flavor to the tempeh juice drink. On manufacture Tempe juice drink Emprit ginger extract need addition material CMC stabilizer for increase stability and viscosity product . Study This aim To determine the economic feasibility, an economic analysis was carried out regarding the feasibility of applying tempeh juice in the tempe industry. The research begins with making assumptions and analyzing the parameters, components and cost structure, the need for investment funds and working capital. This parameter calculates projected production, revenue and cash flow. Determination of the economic feasibility of the Tempe juice drink with Emprit ginger extract with the Net Present Value (NPV), Incremental Rate of Return (IRR), Net B/C and Pay Back Period (PBP). The assumption of drinking tempeh juice with emprit ginger extract in a year is 45600 bottles at a price of IDR 10,000.00 / bottle . The proportion of capital comes from 60% own capital and 40% credit. The average operational cost per year is IDR 278.606.467.00, variable costs Rp 233.606.467.00, and a flat fee of Rp 45.000.000.00 . Average income per year Rp 319.200,000.00 while spending Rp 304.017.802.00. The profit earned is Rp 151.982.198. Sales profit 2 8.33 % with 15% tax per year. This business BEP occurs in sales with an average value of Rp. 151.982.198 or 33,33 % of production capacity per year. The results showed that the NPV was Rp 156.180.415, IRR is 53 %, and Net B/C is 1.82 times. Based on existing criteria or assumptions, this business is feasible to run with PBP for two years, or the capital invested in this business can be returned before the project ends (3 many years).

Domestic greywater treatment using electrocoagulation-electrooxidation process: optimisation and experimental approaches

A synergistic combination of electrocoagulation-electrooxidation (EC-EO) process was used in the current study to treat domestic greywater. The EC process consisted of an aluminium (Al) anode and an iron (Fe) cathode, and the EO process consisted of titanium with platinum coating mesh (Ti/Pt) as an anode and stainless steel as a cathode. The effect of operative variables, namely current density, pH, EC time and EO time, on the removal of chemical oxygen demand (COD), colour, turbidity, and total organic carbon (TOC) was studied and optimised using Response Surface Methodology (RSM). The results showed that although the pH affected the removal of all studied pollutants, it had more effect on turbidity removal with a contribution of 88.44%, while the current density had the main dominant effect on colour removal with a contribution of 73.59%. It was also found that at optimal operation conditions for a current density of 2.6 A, an initial pH of 4.67, an EC time of 31.67 min, and an EO time of 93.28 min led to a COD, colour, turbidity, and TOC removal rates of 96.1%, 97.5%, 90.9%, and 98%, respectively, which were close to the predicted results. The average operating cost and energy consumption for the removal of COD, colour, turbidity, and TOC were 0.014 $/m3 and 0.01 kWh/kg, 0.083 $/m3 and 0.008 kWh/kg, 0.075 $/m3 and 0.062 kWh/kg, and 0.105 $/m3 and 0.079 kWh/kg, respectively.

A branch-and-price method for a two-echelon location routing problem with recommended satellites

In city logistics, the two-echelon location routing problem is crucial in coordinating resources and radiating nodes, enabling the efficient planning of relay stations and vehicle distribution routes. However, with the expansion of distribution scopes and changes in urban development, fixed relay stations may not be able to adapt to the evolving network demand structure, leading to reduced efficiency. This paper proposes a two-echelon location routing problem with recommended satellites (2E-LRPRS) to address this issue. These satellites are chosen from the customer set and can be reoptimized to enhance the network's adaptability. A mixed-integer linear program (MILP) is formulated to minimize the distribution cost of the two-echelon network. To solve this problem, a column-generation algorithm (CG) is proposed, which decomposes the original problem into a linear relaxation main problem and a series of two-stage shortest-path subproblems with resource constraints. The branch-and-pricing algorithm (B&P) is then designed to obtain the integer solution. The experimental results demonstrate that the proposed B&P is significantly more efficient and effective than the MILP solver - Cplex. Furthermore, by selecting relay stations from customers, the recommended satellites can be flexibly adjusted based on the locations and demands of distribution customers, leading to an average operating cost savings of 8.43%.

Cost Comparison of Highway Rest Area Operations: In-House Workforce versus Outsourcing Methods

State departments of transportation (DOTs) typically use one of three approaches to operate highway rest areas (RAs): in-house workforce, method-based contracting (MBC), and performance-based contracting (PBC). State DOTs spend over $600 million annually to maintain their facilities and often outsource their work to save costs. Although some studies have calculated the annual cost of facilities operated by the three approaches, their findings are not directly comparable. The primary objective of this study is to compute and compare the average annual operating cost of individual RA facilities and the cost of RA data samples (average annual operating cost of a group of facilities in a specific year under a specific approach in a state) produced from these three approaches to achieve a cost-effective alternative. To achieve the objectives, research hypotheses were developed which state there are significant differences in the average annual costs produced by these three approaches. For data analysis, 6,248 cost data were collected from 29 states. From those individual cost data, 198 data samples were generated. Data sets were not normally distributed; thus, nonparametric tests were conducted to determine the group differences. The results show that outsourcing costs under the MBC are significantly less, followed by in-house and the PBC in both cases. The difference between in-house and PBC is also statistically significant. As the primary contribution, this paper investigated the MBC approach as the cost-effective option, and DOT engineers can utilize this approach in operating regular RA facilities to save costs. Caution should be taken when using the study findings in other types of facilities.

Reinforcement learning and mixed-integer programming for power plant scheduling in low carbon systems: Comparison and hybridisation

Decarbonisation is driving dramatic growth in renewable power generation. This increases uncertainty in the load to be served by power plants and makes their efficient scheduling, known as the unit commitment (UC) problem, more difficult. UC is solved in practice by mixed-integer programming (MIP) methods; however, there is growing interest in emerging data-driven methods including reinforcement learning (RL). In this paper, we extensively test two MIP (deterministic and stochastic) and two RL (model-free and with lookahead) scheduling methods over a large set of test days and problem sizes, for the first time comparing the state-of-the-art of these two approaches on a level playing field. We find that deterministic and stochastic MIP consistently produce lower-cost UC schedules than RL, exhibiting better reliability and scalability with problem size. Average operating costs of RL are more than 2 times larger than stochastic MIP for a 50-generator test case, while the cost is 13 times larger in the worst instance. However, the key strength of RL is the ability to produce solutions practically instantly, irrespective of problem size. We leverage this advantage to produce various initial solutions for warm starting concurrent stochastic MIP solves. By producing several near-optimal solutions simultaneously and then evaluating them using Monte Carlo methods, the differences between the true cost function and the discrete approximation required to formulate the MIP are exploited. The resulting hybrid technique outperforms both the RL and MIP methods individually, reducing total operating costs by 0.3% on average.

ANALISIS BIAYA SATUAN OPERASIONAL NON PERSONALIA BERBASIS STANDAR KEBUTUHAN KOMPETENSI DI SMK

This research is a qualitative research with a Descriptive Observational Case Studies approach which aims to obtain the factual non-personnel operational unit cost average required for the Competency of Computer and Network Engineering Skills at SMK Negeri 2 Bone. The research samples were school principals, deputy principals, BOS treasurers, administrative staff, heads of computer and network engineering competency skills computer and network engineering (TKJ) skills competency teachers at SMK Negeri 2 Bone. Data collection techniques through interviews, observation, questionnaire techniques and documentation. The data analysis technique used is qualitative analysis of flowing or interactive analysis models. This model consists of three components of analysis, namely data reduction, data presentation, and drawing conclusions or verification. The results of the study show that the average non-personnel operational unit cost in fact required for the Computer and Network Engineering Skills Competency at SMK Negeri 2 Bone in 2023 is Rp. 168.409,300, - using the current year's calculations and the number of students is 103 people spread across Class X, Class XI and Class XII.

Study Produktivitas dan Perbandingan Produktivitas dan Efisiensi Kegiatan Penebangan Mekanis Tanaman Eucalyptus sp. Di Hutan Tanaman Industri

The use of wood harvesting equipment greatly helps the company to achieve the goals, namely: (1) speed up the process of carrying out work; (2) carrying out the kind of work that cannot be done by human labor; and (3) it is done for reasons of efficiency, limited labor, security and economic factors. Therefore, in order for the goal to be achieved, it is necessary to choose tools that are appropriate, economical and in accordance with working conditions. The selection of inappropriate tools can result in not achieving the expected goals and can cause damage to the tool itself. In the process of logging carried out at PT. RAPP on fully mechanical and semi-mechanical systems uses different logging tools. Each tool in logging activities has its own disadvantages and advantages. So it is necessary to conduct research on comparing the productivity and efficiency of logging using chainsaws and excavator attachment tree shear on Eucalyptus sp plants. Based on the results of the test analysis conducted, the average chainsaw productivity of STIHL MS 382 was 11.32 m³ / hour smaller than the productivity of excavator KOBELCO SK-130 HD with attachman tree shear Dymax 14 In " of 27.34 m³ / hour. As for the average operational cost of the STIHL MS 382 chainsaw of Rp. 7,043/m³ smaller than excavator KOBELCO SK-130 HD with attachman tree shear Dymax 14 In" of Rp. 11.541/ m³.