A Heuristic Approach for GPS-Based Routing LeBlanc, Larry J; Grossman, Thomas A
International journal of interdisciplinary telecommunications and networking,
10/2021, Letnik:
13, Številka:
4
Journal Article
Recenzirano
Vehicle routing (such as for package delivery) presents challenges for operations planning and operations control. Planning ensures that vehicles are assigned to “good” routes, and control enables ...routes to be changed in real time in response to changes in destination requirements. Both planning and control can be accomplished using web-based, intelligent geographic information system tools to rapidly generate a heuristic solution using an embedded algorithm, rather than the established approach of using explicit customized optimization models. The authors contrast the established approach of using customized integer optimization models to a heuristic that integrates human judgment with Google Maps travel time data to solve vehicle routing problems. This paper discusses the data requirements, simplifying assumptions, and practical performance of both approaches. The advantage of the heuristic approach is that genuine, useful access to much of the power of highly sophisticated OR network models can be provided to large numbers of analytically unsophisticated managers, along with enhanced operational control.
We describe a student-centered approach for the required business school management science course. We articulate three principles for teaching management science to business students: real-world ...context, spreadsheet-native attitude, and student self-efficacy. We examine the implications of these principles and how they affect course content and delivery. We show how to establish relevance as perceived by business students. We highlight the business analysis lifecycle as a valuable “roadmap” for students and instructors alike. We explain costs, benefits, and techniques for spreadsheet-native modeling. Spreadsheet modeling should be treated as a computer programming process, based on the properties of the spreadsheet programming language. We explain how and why to separate the modeling process from the act of typing into a spreadsheet. Spreadsheets can function as valuable organizational assets. We candidly discuss the challenges faced transitioning from a tools-based teaching approach to a student-centered approach.
Logistics optimization has significantly grown in popularity over the last few decades. Improvements in computing power, modeling software, and the willingness of companies to invest time in the ...modeling effort have allowed models that were once too unwieldy to solve to optimality to be solved quickly. This has led to a more wide‐spread recognition by logistics managers of the potential advantages of using optimization. The scope of logistics optimization in companies and organizations has expanded to address strategic, tactical, operational, and collaborative decision making. Spreadsheets, an analytical tool familiar to managers, have played a crucial role in the expanded modeling efforts of companies. Although optimization’s role in logistics has grown tremendously, there still are areas that remain to be explored that will allow it to achieve an even larger and more successful role in the management of companies. Additionally, there are some models that are still too large or too complex to currently solve to optimality, despite the advances in computing power and modeling/solving software.
More than 25% of patients with AML carry no mutations in genes known to be associated with leukemia. Analyses of genomes, transcriptomes, and methylomes of AML samples implicate mutations in ...cytogenetically normal AML and provide insight into the relationships among causative genes.
The molecular pathogenesis of acute myeloid leukemia (AML) has been studied with the use of cytogenetic analysis for more than three decades. Recurrent chromosomal structural variations are well established as diagnostic and prognostic markers, suggesting that acquired genetic abnormalities (i.e., somatic mutations) have an essential role in pathogenesis.
1
,
2
However, nearly 50% of AML samples have a normal karyotype, and many of these genomes lack structural abnormalities, even when assessed with high-density comparative genomic hybridization or single-nucleotide polymorphism (SNP) arrays
3
–
5
(see Glossary). Targeted sequencing has identified recurrent mutations in
FLT3, NPM1, KIT, CEBPA,
and
TET2
.
6
–
8
Massively parallel . . .
The COVID-19 pandemic has forced the rapid adoption of remote teaching modalities including “hyflex” where students attend some class sessions in person and some online. Managing the hyflex course ...requires faculty to quickly generate several reports and to update these reports rapidly when the authorities adjust the rules, students add/drop, or the number of course sessions is changed. The creation of these reports is tedious and error-prone, so they need to be automated. However, the nature of the task precludes traditional Excel programming approaches. We use Excel’s new “dynamic array” capabilities (which are available only in Excel 365) to automate the creation and updating of the reports needed to manage the hyflex course. We show how to program the reports, and we discuss the importance of taking an iterative approach to creating effective, error-free cell formulas. To help the reader acquire genuine access to the dynamic array functions, we provide a practical tutorial on the principles and new concepts of dynamic arrays, explain how they relate to legacy array functions, and present selected dynamic array functions including SEQUENCE, FILTER, and XLOOKUP.
•Eliminates the challenge of scaling spreadsheet linear programming models.•Spreadsheet LPs can now be re-used and re-optimized as easily as algebraic models.•Enables fully reusable code for ...spreadsheet models.•Operates in native Excel without use of macros or VBA.•Works for any LP with up to 1 million non-zero constraint coefficients.
Linear programming models implemented in spreadsheets are understood to be difficult to reuse, whether with modified data that increases or decreases model scale (such as routine model maintenance), as well as with new data (such as deploying a model to a new business setting). The difficulty arises because spreadsheets commingle cell formulas with data, which requires editing cell formulas when the data changes. We provide a novel technique to implement a linear programming model in a spreadsheet that allows for full re-use of the spreadsheet code. It robustly accommodates modified or new data, and enables a spreadsheet LP easily to be reused or even deployed to a new setting with an entirely new dataset. This technique applies to any linear programming model up to approximately 1 million non-zero constraint coefficients, and operates in native Excel without use of macros or VBA. Spreadsheet LP models can now be re-used, re-deployed, and re-optimized as easily as with algebraic software.
Lessons from Mission-Critical Spreadsheets Grossman, Thomas A.; Mehrotra, Vijay; Özlük, Özgür
Communications of the Association for Information Systems,
2007, Letnik:
20
Journal Article
Recenzirano
Odprti dostop
We present eighteen examples of mission-critical spreadsheets used by diverse people and organizations for application software development, financial risk management, executive information systems, ...sales and marketing business processes, business operations, and complex analytics. We argue the spreadsheet is a Rapid Development Language, an Integrated Development Environment, and a Fourth Generation Language, and has unusual challenges regarding source code protection. We note that intentional spreadsheet applications are largely absent from the error literature. We explain why people might prefer a spreadsheet to an application developed by the IT department, and show how some spreadsheet programmers choose to avoid--or do not have--an IT department. We find that 1) Spreadsheets are widely used for mission-critical functions; 2) Spreadsheets are an effective application development platform; 3) There is diversity of development skill in creators of mission-critical spreadsheets; 4) Sophisticated programmers sometimes choose spreadsheets over other languages; 5) Spreadsheets are amenable to formal development practices, but such practices seem rare; 6) Spreadsheets play a central role in the evolution of business processes and work systems; and 7) Spreadsheets are a source of "accidental legacy systems". We provide the Skill-User Programming Paradigm to help interpret and explain our observations. We conclude that spreadsheets are vitally important to business, and merit sustained research to discover techniques to enhance quality, productivity, and maintainability.
Many service industries (e.g., walk-in clinics, vehicle inspection facilities, and data-processing centers) have customers who choose among congested facilities, and select the facility with the ...lowest combination of travel cost plus congestion cost at the facility. In general, customers over-utilize attractive facilities, causing higher costs than if customers were assigned to facilities to minimize total costs. Optimal facility prices induce customers to select facilities that minimize total cost. We find optimal facility prices and show they equal charging customers for the impact (net costs and benefits) they cause for others. We explore a rich flexibility that allows a range of optimal prices, useful when negotiating the implementation of facility fees. Facility prices can be positive or negative (price discounts), and can be adjusted to be all positive, or to provide net subsidy or net revenue. We contribute to unifying and generalizing several disparate streams of research.
Operations research practitioners often write spreadsheet software that is used, modified, and transferred to other people over time. They need techniques that enable them to quickly write error-free ...code whose accuracy can be easily verified and tested. Practitioner spreadsheet models often must be suitable for transfer to others and be robust in the sense that inadvertently introducing errors during reuse and updating is difficult. We examine some problem areas for spreadsheet design and programming and suggest techniques intended to increase productivity and reduce the risk of errors, especially in situations in which someone other than the original author is using or maintaining the spreadsheets.
Somatic variants, primarily fusion genes and single-nucleotide variants (SNVs) or insertions/deletions (indels), are prevalent among sarcomas. In many cases, accurate diagnosis of these tumors ...incorporates genetic findings that may also carry prognostic or therapeutic significance. Using the anchored multiplex PCR–based FusionPlex system, a custom RNA sequencing panel was developed that simultaneously detects fusion genes, SNVs, and indels in 112 genes found to be recurrently mutated in solid tumors. Using this assay, a retrospective analysis was conducted to identify somatic variants that may have assisted with classifying a cohort of 90 previously uncharacterized primarily pediatric sarcoma specimens. In total, somatic variants were identified in 45.5% (41/90) of the samples tested, including 22 cases with fusion genes and 19 cases with SNVs or indels. In addition, two of these findings represent novel alterations: a WHSC1L1/NCOA2 fusion and a novel in-frame deletion in the NRAS gene (NM_002524: c.174_176delAGC p.Ala59del). These sequencing results, taken in context with the available clinical data, indicate a potential change in the initial diagnosis, prognosis, or management in 27 of the 90 cases. This study presents a custom RNA sequencing assay that detects fusion genes and SNVs in tandem and has the ability to identify novel fusion partners. These features highlight the advantages associated with utilizing anchored multiplex PCR technology for the rapid and highly sensitive detection of somatic variants.
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