A review of network location theory and models

Cataloged from PDF version of article.In this study, we review the existing literature on network location problems. The study has a broad scope that includes problems featuring desirable and undesirable facilities, point facilities and extensive facilities, monopolistic and competitive markets, and single or multiple objectives. Deterministic and stochastic models as well as robust models are covered. Demand data aggregation is also discussed. More than 500 papers in this area are reviewed and critical issues, research directions, and problem extensions are emphasized.Erdoğan, Damla SelinM.S

The Multi-Depot Minimum Latency Problem with Inter-Depot Routes

The Minimum Latency Problem (MLP) is a class of routing problems that seeks to minimize the wait times (latencies) of a set of customers in a system. Similar to its counterparts in the Traveling Salesman Problem (TSP) and Vehicle Routing Problem (VRP), the MLP is NP-hard. Unlike these other problem classes, however, the MLP is customer-oriented and thus has impactful potential for better serving customers in settings where they are the highest priority. While the VRP is very widely researched and applied to many industry settings to reduce travel times and costs for service-providers, the MLP is a more recent problem and does not have nearly the body of literature supporting it as found in the VRP. However, it is gaining significant attention recently because of its application to such areas as disaster relief logistics, which are a growing problem area in a global context and have potential for meaningful improvements that translate into reduced suffering and saved lives. An effective combination of MLP\u27s and route minimizing objectives can help relief agencies provide aid efficiently and within a manageable cost. To further the body of literature on the MLP and its applications to such settings, a new variant is introduced here called the Multi-Depot Minimum Latency Problem with Inter-Depot Routes (MDMLPI). This problem seeks to minimize the cumulative arrival times at all customers in a system being serviced by multiple vehicles and depots. Vehicles depart from one central depot and have the option of refilling their supply at a number of intermediate depots. While the equivalent problem has been studied using a VRP objective function, this is a new variant of the MLP. As such, a mathematical model is introduced along with several heuristics to provide the first solution approaches to solving it. Two objectives are considered in this work: minimizing latency, or arrival times at each customer, and minimizing weighted latency, which is the product of customer need and arrival time at that customer. The case of weighted latency carries additional significance as it may correspond to a larger number of customers at one location, thus adding emphasis to the speed with which they are serviced. Additionally, a discussion on fairness and application to disaster relief settings is maintained throughout. To reflect this, standard deviation among latencies is also evaluated as a measure of fairness in each of the solution approaches. Two heuristic approaches, as well as a second-phase adjustment to be applied to each, are introduced. The first is based on an auction policy in which customers bid to be the next stop on a vehicle\u27s tour. The second uses a procedure, referred to as an insertion technique, in which customers are inserted one-by-one into a partial routing solution such that each addition minimizes the (weighted) latency impact of that single customer. The second-phase modification takes the initial solutions achieved in the first two heuristics and considers the (weighted) latency impact of repositioning nodes one at a time. This is implemented to remove potential inefficient routing placements from the original solutions that can have compounding effects for all ensuing stops on the tour. Each of these is implemented on ten test instances. A nearest neighbor (greedy) policy and previous solutions to these instances with a VRP objective function are used as benchmarks. Both heuristics perform well in comparison to these benchmarks. Neither heuristic appears to perform clearly better than the other, although the auction policy achieves slightly better averages for the performance measures. When applying the second-phase adjustment, improvements are achieved and lead to even greater reductions in latency and standard deviation for both objectives. The value of these latency reductions is thoroughly demonstrated and a call for further research regarding customer-oriented objectives and evaluation of fairness in routing solutions is discussed. Finally, upon conclusion of the results presented in this work, several promising areas for future work and existing gaps in the literature are highlighted. As the body of literature surrounding the MLP is small yet growing, these areas constitute strong directions with important relevance to Operations Research, Humanitarian Logistics, Production Systems, and more

NASA space station automation: AI-based technology review

Research and Development projects in automation for the Space Station are discussed. Artificial Intelligence (AI) based automation technologies are planned to enhance crew safety through reduced need for EVA, increase crew productivity through the reduction of routine operations, increase space station autonomy, and augment space station capability through the use of teleoperation and robotics. AI technology will also be developed for the servicing of satellites at the Space Station, system monitoring and diagnosis, space manufacturing, and the assembly of large space structures

Autochthonous and Introduced Stores of Biomass Value: Measuring Resilience Outcomes of Enset and Eucalyptus as Green Assets in Three Representative Smallholder Farm Systems of Ethiopia

Fundamental shifts in the ability to observe our world with synoptic satellite remote sensing and the profusion of trend tracking longitudinal data sources not only better inform us of the mounting trouble our planet is in but also provide completely new perspectives on basic shared understandings, such as how many trees grow on Earth and where they take root. Observing the dispersed pattern of increasing tree cover across a multidecadal satellite mosaic, developed by Matt Hansen and colleagues at University of Maryland at College Park, sparked an interest in the ramifications of this unanticipated change, marked clearly upon the landscape in Ethiopia. The following chapters explore the relation of changing amounts of autochthonous treelike perrenial enset and introduced eucylyptus trees, commonly found on Ethiopian farms, to smallholder resilience, food security, and well-being. Spatially informed longitudinal models for three representative subnational data sets are used to investigate the central thesis of this dissertation—trees and treelike perennials on farms in rural Ethiopia indicate a fundamental store of value in living biomass, building a household’s assets over time through improved biomass management, for resilient small farm livelihoods that ensure food security and related well-being. Green assets acting as biomass stores indicate natural “value,” representing transformed and stored energy of the sun, that Blaikie and Brookfield (1987) considered inadequately captured as a no-cost contribution to the “use value” concept in development economics, economic geography production, and income-focused research, as well as in Marx’s (1887/2013) labor-focused value constructs that only briefly acknowledge workers are helped by the transformative “natural forces” at work on the land. Model results presented in Chapters 3, 4, and 5 reveal a lack of on-farm trees and treelike perennials often indicates biomass poverty and energy insecurity. Chronic biomass poverty, measured with spatially aware hierarchal models, is related to an inability to maintain a sufficient level of essential green assets, thereby contributing to poor resilience and well-being outcomes on small farms. On the other hand, medium and longer term asset accumulation supports improved well-being when livelihood strategies make use of farm forests, other on-farm trees, and treelike perennials

Determining the Value of Future Information

Companies continuously struggle to quantify the value of their information in an attempt to gain a better understanding of the return on investment of their information technology (IT) architecture. One approach companies have taken to place a numeric value on information is to treat it as a traditional economic asset (e.g. equipment, buildings, and vehicles) that is governed by its own unique set of laws. Once an enterprise understands the behavior of information it can incorporate Skyrme\u27s 10 value adding aspects of information when developing IT architecture, thus maximizing the potential value of their information. Like most enterprises, the Intelligence Community (IC) is continuously trying to assess the value of their Intelligence Sharing Architecture. Currently, work is being done inside the Department of Defense (DoD) using Value Focused Thinking (VFT) to compare the value of different Intelligence, Surveillance and Reconnaissance (ISR) force mixtures. The current ISR force sizing study is very beneficial for evaluating today\u27s ISR force mixtures, but little research has been done to evaluate the ISR force mixtures of the future. This research will present a generic methodology allowing any enterprise to determine the value of future IT architecture; specifically, it will be applied to the IC for determining the value of intelligence gathering capabilities for the year 2040

Water Resources Planning, Social Goals, and Indicators: Methodological Development and Empirical Test

A methodology for comprehensive evaluation of water resources development and use (Techcom) has been developed and partially field tested. A model of societal goals consists of nine primary goals successively articualted into increasingly specific subgoals. Achievement of subgoals is perceived as affected by measurable social indicators whose values are perturbed by water resources actions. Linking the elements of the goals taxon by connectives result in an evaluation system. historical, political and philosophical considerations of the proposed system are discussed in Part I. Part II describes the results of the Rio Grande of New Mexico test including public perception and weighting of the subgoals and goals, and development of specific connectives. Future values of 128 social indicators for 5 action plans for four 5-year intervals to 1987 are estimated using a computerized system based on an inversion of an input-output model interacting with social and environmental indicator connectives. A computerized system for quantified planning inquiry provides comparisons of relative goal achievement and permits review of all planning information through a simple retrieval procedure providing visual display or hard copy. The methodology is conveived as applicable generally to natural resources actions

one6G white paper, 6G technology overview:Second Edition, November 2022

6G is supposed to address the demands for consumption of mobile networking services in 2030 and beyond. These are characterized by a variety of diverse, often conflicting requirements, from technical ones such as extremely high data rates, unprecedented scale of communicating devices, high coverage, low communicating latency, flexibility of extension, etc., to non-technical ones such as enabling sustainable growth of the society as a whole, e.g., through energy efficiency of deployed networks. On the one hand, 6G is expected to fulfil all these individual requirements, extending thus the limits set by the previous generations of mobile networks (e.g., ten times lower latencies, or hundred times higher data rates than in 5G). On the other hand, 6G should also enable use cases characterized by combinations of these requirements never seen before, e.g., both extremely high data rates and extremely low communication latency). In this white paper, we give an overview of the key enabling technologies that constitute the pillars for the evolution towards 6G. They include: terahertz frequencies (Section 1), 6G radio access (Section 2), next generation MIMO (Section 3), integrated sensing and communication (Section 4), distributed and federated artificial intelligence (Section 5), intelligent user plane (Section 6) and flexible programmable infrastructures (Section 7). For each enabling technology, we first give the background on how and why the technology is relevant to 6G, backed up by a number of relevant use cases. After that, we describe the technology in detail, outline the key problems and difficulties, and give a comprehensive overview of the state of the art in that technology. 6G is, however, not limited to these seven technologies. They merely present our current understanding of the technological environment in which 6G is being born. Future versions of this white paper may include other relevant technologies too, as well as discuss how these technologies can be glued together in a coherent system

The right to human dignity : a study of communal water and sanitation facilities for the peri-urban settlement of Inanda.

Master of Architecture. University of KwaZulu-Natal, Durban, 2015.Sustainable urban sanitation presents one of the many challenges towards service delivery and is directly related to poverty alleviation. Without appropriate social infrastructure such as water and sanitation - communities in the developing world can easily spiral into a decline. Water and appropriate sanitation, centre on community building and support communities to achieve high standards of health, equality, and good quality housing, good schools, safe, clean and friendly neighbourhoods. Without these social support infrastructure, peri-urban settlements struggle to become cohesive, and living communities with a sense of place, belonging or identity. In the developing world, communities without access to water and sanitation facilities suffer from a wide range of social problems and a platform for social discourse. Women are closely related to sanitation and water usage due to their social responsibilities at home and within their communities. Women tend to manage households and are the primary caregivers to children and extended family, also playing a nurturing role for the vulnerable, disabled and sick in the community. In South Africa, women living in rural and peri-urban areas face significant challenges. They live within a cycle of poverty, without appropriate access to a private toilets or to clean drinking water at the home. This research paper sets out to achieve an understanding of the daily living conditions communities face both spatially and programmatically, with a focus on women living in the peri-urban settlement of Inanda Durban. The objective set out tackles how architecture can be envisioned to meet dignified possibilities for and enrich the livelihoods of communities through the provision of appropriate and sustainable and suitable water and sanitation

Organization strategy, management techniques and management accounting practices : contingency research in Thailand

There have been the recent calls for additional research in order to enhance the understanding of potential contingency factors which explain the adoption of management accounting practices (MAPs). This, allied to a lack of knowledge in relation to current use of MAPs, especially in developing countries, is the motivation for this research. Thus, this research attempts to explore the adoption and perceived benefit of MAPs as well as to examine their relationships with contingency factors affecting organizational performance in a developing country, Thailand. Two potential contingency factors are adopted for this research including a comprehensive set of strategic typologies and management techniques (MTs). Three forms of contingency fit, selection, interaction, and systems approaches, have been adopted in order to develop research questions and hypotheses.A triangulation approach combining a survey and interviews is used in this research. The questionnaire was delivered to 'accounting managers' of 451 companies listed on the Stock Exchange of Thailand (SET). There were 135 returned and usable responses, resulting in 29.9 percent response rate. Semi-structured interviews of seven companies provide qualitative findings, which are in line with, but explain further, those from the survey.The findings confirm the popularity of the use of, and high perceived benefit from, traditional MAPs and reveal disappointing adoption rates of, and relatively low perceived benefit from, contemporary MAPs. There are some alignments between MAPs and strategic typologies and between MTs and strategic typologies. However, only a few moderation effects are detected. In line with expectations, the companies under differentiation/ prospector/ entrepreneurial/ build strategies tend to have higher organizational performance when they obtain higher benefit from contemporary MAPs and MTs concerning quality, employee empowerment, customization and flexibility. It was also found that the companies pursuing cost leadership/ defender/ conservative/ harvest strategies tend to have higher performance when they obtain higher benefit from traditional MAPs and MTs relating to cost reduction processes.This study adds to the limited body of knowledge of MA in Asian countries, in particular Thailand. It represents a comprehensive survey and explanation of MAPs in Thailand. It is anticipated that this research will make academics and practitioners aware of the capability of alternative MAPs combined with the right match of MTs to improve firms' efficiency and effectiveness as well as its fit with the strategies. It is also expected that the findings of this research will provide valuable insights into the nature of MAPs, and assist the academics and practitioners in improving management accounting rules and practices in Thailand