Designing a locating-routing three-echelon supply chain network under uncertainty

PurposeIn the present research, location and routing problems, as well as the supply chain, which includes manufacturers, distributor candidate sites and retailers, are explored. The goal of addressing the issue is to reduce delivery times and system costs for retailers so that routing and distributor location may be determined.Design/methodology/approachBy adding certain unique criteria and limits, the issue becomes more realistic. Customers expect simultaneous deliveries and pickups, and retail service start times have soft and hard time windows. Transportation expenses, noncompliance with the soft time window, distributor construction, vehicle purchase or leasing, and manufacturing costs are all part of the system costs. The problem's conceptual model is developed and modeled first, and then General Algebraic Modeling System software (GAMS) and Multiple Objective Particle Swarm Optimization (MOPSO) and non-dominated sorting genetic algorithm II (NSGAII) algorithms are used to solve it in small dimensions.FindingsAccording to the mathematical model's solution, the average error of the two suggested methods, in contrast to the exact answer, is less than 0.7%. In addition, the performance of algorithms in terms of deviation from the GAMS exact solution is pretty satisfactory, with a divergence of 0.4% for the biggest problem (N = 100). As a result, NSGAII is shown to be superior to MOSPSO.Research limitations/implicationsSince this paper deals with two bi-objective models, the priorities of decision-makers in selecting the best solution were not taken into account, and each of the objective functions was given an equal weight based on the weighting procedures. The model has not been compared or studied in both robust and deterministic modes. This is because, with the exception of the variable that indicates traffic mode uncertainty, all variables are deterministic, and the uncertainty character of demand in each level of the supply chain is ignored.Practical implicationsThe suggested model's conclusions are useful for any group of decision-makers concerned with optimizing production patterns at any level. The employment of a diverse fleet of delivery vehicles, as well as the use of stochastic optimization techniques to define the time windows, demonstrates how successful distribution networks are in lowering operational costs.Originality/valueAccording to a multi-objective model in a three-echelon supply chain, this research fills in the gaps in the link between routing and location choices in a realistic manner, taking into account the actual restrictions of a distribution network. The model may reduce the uncertainty in vehicle performance while choosing a refueling strategy or dealing with diverse traffic scenarios, bringing it closer to certainty. In addition, two modified MOPSO and NSGA-II algorithms are presented for solving the model, with the results compared to the exact GAMS approach for medium- and small-sized problems.

TBS-BAO: fully automated beam angle optimization for IMRT guided by a total-beam-space reference plan

Properly selected beam angles contribute to the quality of radiotherapy treatment plans. However, the Beam Angle Optimization (BAO) problem is difficult to solve to optimality due to its non-convex discrete nature with many local minima. In this study, we propose TBS-BAO, a novel approach for solving the BAO problem, and test it for non-coplanar robotic CyberKnife radiotherapy for prostate cancer. First, an ideal Pareto-optimal reference dose distribution is automatically generated using a priori multi-criterial fluence map optimization (FMO) to generate a plan that includes all candidate beams (total-beam-space, TBS). Then, this ideal dose distribution is reproduced as closely as possible in a subsequent segmentation/beam angle optimization step (SEG/BAO), while limiting the number of allowed beams to a user-selectable preset value. SEG/BAO aims at a close reproduction of the ideal dose distribution. For each of 33 prostate SBRT patients, 18 treatment plans with different pre-set numbers of allowed beams were automatically generated with the proposed TBS-BAO. For each patient, the TBS-BAO plans were then compared to a plan that was automatically generated with an alternative BAO method (Erasmus-iCycle) and to a high-quality manually generated plan. TBS-BAO was able to automatically generate plans with clinically feasible numbers of beams (∽25), with a quality highly similar to corresponding 91-beam ideal reference plans. Compared to the alternative Erasmus-iCycle BAO approach, similar plan quality was obtained for 25-beam segmented plans, while computation times were reduced from 10.7 hours to 4.8/1.5 hours, depending on the applied pencil-beam resolution in TBS-BAO. 25-beam TBS-BAO plans had similar quality as manually generated plans with on average 48 beams, while delivery times reduced from 22.3 to 18.4/18.1 min. TBS reference plans could effectively steer the discrete non-convex BAO.

Logistics Performance, Ratings, and Its Impact on Customer Purchasing Behavior and Sales in E-Commerce Platforms

Problem definition: We examine the impact of logistics performance metrics such as delivery time and customer’s requested delivery speed on logistics service ratings and third-party sellers’ sales on an e-commerce platform. Academic/practical relevance: Although e-commerce retailers like Amazon have recently invested heavily in their logistics networks to provide faster delivery to customers, there is scant academic literature that tests and quantifies the premise that convenient and fast delivery will drive sales. In this paper, we provide empirical evidence on whether this relationship holds in practice by analyzing a mechanism that connects delivery performance to sales through logistics ratings. Prior academic work on online ratings in e-commerce platforms has mostly analyzed customers’ response to product functional performance and biases that exist within. Our study contributes to this stream of literature by examining customer experience from a service quality perspective by analyzing logistics service performance, logistics ratings, and its impact on customer purchase probability and sales. Methodology: Using an extensive data set of more than 15 million customer orders on the Tmall platform and Cainiao network (logistics arm of Alibaba), we use the Heckman ordered regression model to explain the variation in customers’ rating of logistics performance and the likelihood of customers posting a logistics rating. Next, we develop a generic customer choice model that links the customer’s likelihood of making a purchase to the logistics ratings provided by prior customers. We implement a two-step estimation of the choice model to quantify the impact of logistics ratings on customer purchase probability and third-party seller sales. Results: We surprisingly find that even customers with no promise on delivery speed are likely to post lower logistics ratings for delivery times longer than two days. Although these customers are not promised an explicit delivery deadline, they seem to have a mental threshold of two days and expect deliveries to be made within that time. Similarly, we find that priority customers (those with two-day and one-day promise speed) provide lower logistics ratings for delivery times longer than their anticipated delivery date. We estimate that reducing the delivery time of all three-day delivered orders on this platform (which makeup [Formula: see text] 35% of the total orders) to two days would improve the average daily third-party seller sales by 13.3% on this platform. The impact of delivery time performance on sales is more significant for sellers with a higher percentage of three-day delivered orders and a higher spend per order. Managerial implications: Our study emphasizes that delivery performance and logistics ratings, which measure service quality, are essential drivers of the customer purchase decision on e-commerce platforms. Furthermore, by quantifying the impact of delivery time performance on sales, our study also provides a framework for online retailers to assess if the increase in sales because of improved logistics performance can offset the increase in additional infrastructure costs required for faster deliveries. Our study’s insights are relevant to third-party sellers and e-commerce platform managers who aim to improve long-term online customer traffic and sales.

PENGEMBANGAN SOP (STANDART OPERATING PROSEDURES) PELAPORAN GANGGUAN DENGAN METODE GAP ANALYSIS

PT.XYZ Pekanbaru sector was formed through the decision of the board of directors number 001.k/023/DIR/1996 dated February 7, 1996. It can be seen that one of PT.PLN's service activities is receiving reports of disturbances from service units. In reporting the disturbances received by the Operations and Maintenance Department (OPHAR), there were still several problems with disturbances from each service unit (UL), namely (ULPTG) Teluk Lembu, (PLTA) Koto Panjang, and (PLTG/MG) Duri, in reporting disturbance, the information provided is not detailed so that the information received is not in accordance with the needs of the operation and selection department, there is no schedule for sending disturbance reports, disturbance reports are past schedule when there is a disturbance and long delivery times, and there is no evaluation report and recommendation report from the unit. services as well as the absence of a chronology of disturbance validation reports. By conducting a gap analysis, we will compare the current conditions with the ideal conditions expected by the OPHAR department regarding the current SOP for reporting disturbances. From the results of the gap analysis, it can be concluded that there are 2 (two) SOP procedures that have gaps because they are not in accordance with the company's EAM standards.

LITERATURE REVIEW : EFEKTIFITAS PELVIC ROCKING EXERCISE MENGGUNAKAN BIRTHING BALL TERHADAP KEMAJUAN PERSALINAN PADA IBU PRIMIPARA

Indonesia's Health Profile in 2019 in general, there was a decrease in maternal mortality during the period 1991-2015 from 390 to 305 per 100,000 live births, if it is associated with the 2015 Millennium Development Goals (MDGs), namely reducing the maternal mortality rate (MMR) to 102/100,000 live births. the maternal mortality rate did not reach the MDGs target. Physiological efforts are made to prevent prolonged labor, such as pelvic rocking exercise using the birthing ball technique. This is also a method that really helps respond to pain in an active way and reduces the length of the first stage of labor in the active phase. This study aims to determine the effectiveness of the implementation of pelvic rocking with a birthing ball on the progress of labor in primiparous women in 2020. This study uses Systematic Literature Reviews (SLR), which is a synthesis of systematic, clear, comprehensive literature studies, by identifying, analyzing , evaluating through the collection of existing data with an explicit search method and involving a critical review process in the selection of studies. In 6 journals, all journals perform pelvic rocking exercise techniques using the birthing ball technique when the mother enters the first stage of the active phase. The conclusion in this study is that all journals reviewed by researchers can be ascertained that all of these journals get the same results, namely stating that using the Pelvic Rocking Exercise technique with the help of a birthing ball can make delivery times for mothers go faster

IMPROVEMENT OF THE LOGISTIC SERVICE OF RAILWAY FERRY

Purpose. In modern conditions, Ukraine, having an extensive railway network and a developed infrastructure of seaports located on its Black Sea coast, is becoming a link in new goods delivery routes in the direction of the EU-China. Transportation of large consignments of goods in the direction is usually carried out in containers by sea transport. At the same time, such transportation is characterized, on the one hand, by a relatively low cost, and on the other hand, by rather long delivery times. An alternative case is transportation by mixed rail-water communication, which allows, with a moderate increase in cost, to achieve a significant reduction in the delivery time of goods. The economic attractiveness of such a transportation scheme depends significantly on the performance of ferry crossings in the Caspian and Black Seas. In this regard, the purpose of this work is to increase the efficiency of international ferry services by improving its logistics support on coastal ferry complexes. Methodology. To achieve the work purpose, methods of statistical analysis were used to determine the volume and structure of ferry traffic; simulation methods to determine effective options for loading ferries; theory of shunting work to optimize the car classification according to the cargo plan. Results. There were analyzed the requirements for ferry loading and developed a computer model that allows to create acceptable plans for the cars location on ferry decks (cargo plan). On the basis of the obtained variants of the cargo plan, the modeling of the multi-group trains forming by combinatorial and distribution methods has been carried out. Based on the simulation results, recommendations of choosing the effective method for train forming and the required number of cargo plan variants were given. Scientific novelty. The author has improved the method for determining the effective cargo plan of the ferry loading, which takes into account the process of forming the trains of cars to be supplied to the ferry. Practical significance. The obtained results can be used to improve the efficiency of international freight transportation management in mixed rail-water traffic.

Assessing the Effects of Delivery Attributes on E-Shopping Consumer Behaviour

E-consumer behaviour plays a vital role in e-commerce worldwide. This paper addresses the importance of delivery time, delivery fee, and delivery reception, and the influence of delivery fee and reception on e-consumers’ behaviour by analysing the following hypotheses: delivery attributes affect e-shopping behaviour, and delivery attributes affect e-consumers’ behaviour according to their sociodemographic characteristics. Data were obtained from a web-based survey with Brazilian e-consumers, and logistic regression and artificial neural network models were estimated to assess consumer behaviour. We found that delivery fee willingness to pay and privacy are affected by delivery times according to gender. Delivery fees affect the e-consumer according to gender, the habit of purchasing books and leisure products, privacy, promotions, and pricing, and influence the e-shopping decision by age, purchase of electronic products, and promotions. Delivery reception is relevant according to age, income, gender, frequency of e-shopping, privacy, and pricing. Furthermore, delivery fees influence the e-shopping decision by age, purchase of electronic products, and promotions. Finally, delivery fee, willingness-to-pay, and privacy are characteristics influenced by reception on the e-shopping decision. Further analyses would include the dynamic aspects of e-consumer behaviour and the impacts of COVID-19 in the e-consumption patterns and its effects on e-commerce deliveries.

Successful Mitigation of Excessive Backreaming in Troublesome Vertical Applications in the Sultanate of Oman

Drilling through some of the reactive shale formations in the western gas fields in the Sultanate of Oman has proven challenging and often troublesome. Frequently, time spent on backreaming would exceed the time required to drill the related hole sections. In addition, the carbonate Natih sequence has also proven problematic. High levels of vibrations are often encountered. Such drilling dysfunctions are known to be destructive to both bit and bottom hole assembly (BHA). Different mud systems, drive systems and reamer types were used in separate attempts to alleviate the faced dysfunctions to little avail. This paper illustrates a trial campaign introducing an alternative design stabilizer (ADS) and reamer (ADR) to the drilling BHA with the aim of addressing and resolving the aforementioned limiters. Based on a set of agreed-on key performance indicators (KPIs), and following a methodical approach, a 4-well trial was conducted in order to introduce a unique stabilizer-reamer design while simultaneously scrutinizing and optimizing the BHA configuration accordingly. Two of the candidate wells targeted the 17-1/2" section while the other 2 wells targeted the 12-1/4" sections. The main goals were to reduce the time spent on backreaming by 50% and minimize the experienced levels of vibrations in order to extend bit runs and reliability of the different BHA components. For further comparisons, the same approach was tested on a rotary BHA as well as a steerable motor BHA in the larger hole sections. Both 17-1/2" sections were each drilled in a single run similar to the second 12-1/4" section. The first 12-1/4" also proved smooth and required 2 runs due to bit hours, still noting a record section distance run for a single bit. All BHAs were optimized around the placement of the new design stab and reamer design combination. The optimized BHA configuration enabled pulling out of hole (POOH) on elevators for all 4 sections almost fully eliminating the hard backreaming experienced in past wells. In addition, it was also noted that in all cases the levels of vibrations were significantly reduced compared to what is typically experienced and recorded in the offset wells. This enabled a record setting bit run for that particular section and field. The authors detail the historical challenges encountered drilling such wells then present the applied benchmarking exercise and the adopted systematic approach to tackle those challenges. Following, the unique design characteristics of the deployed technology are highlighted and how this is applied in each of the runs in view of optimizing casing point to casing point section delivery times. Finally, the achieved results and gains are underlined together with a roadmap forward.

FLOW CHECK AND ADIABATIC EFFECTIVENESS MEASUREMENTS ON TRADITIONALLY VERSUS ADDITIVELY MANUFACTURED FILM-COOLING HOLES

In the recent years Additive Manufacturing (AM) methods are getting more and more attractive and feasible for the realization of components and subcomponents of gas turbines. They are receiving much attention since, on one hand, the manufacturing of complex 3D geometries is allowed and, on the other, manufacturing and delivery times can be cut down. At the current state of the art, to the authors' knowledge only few applications have yet been commercialized relatively to cooling holes, due to the intrinsic difficulties associated with such a critical feature. Lately, Baker Hughes is studying the possibility to manufacture film-cooling holes via the DMLM technology in order to exploit the flexibility of such innovative manufacturing method and hence eliminate additional processes and lead time. From the open literature it is known that additively manufactured holes can have a more irregular shape and higher roughness than traditional ones, which may lead not only to a reduction in coolant flow but more importantly to a decay of the film-cooling adiabatic effectiveness. For this reason, a test campaign has been conducted in collaboration with the University of Florence (Italy) with the objective of characterizing the performance (minimum passage diameter, flow check and adiabatic effectiveness) of AM vs traditional cylindrical holes on simple-geometry coupons built upon different construction angles. Results were then analyzed in order to fully compare the performance of AM vs traditional film-cooling holes at different operating regimes.