Facility Location

We discuss the connection between facility location prob- lems and covering problems, and present approaches to solving facility location problems by reducing them to cov- ering problems. In particular, we discuss the following NP-hard optimization problems: the set cover and the re- lated set cover facility location problem, the k-center and k-suppliers problem, the dominating set problem, the max- imum

The advantages of logistics centers for companies, cities, and countries have been discussed in the literature and generally mathematical model-based evaluations besides multi-criteria approaches are proposed for site selection processes. However, since mathematical modeling of multiple site selection often turns out to be NP-hard problem structure, it is not always possible to obtain an optimal solution by the solvers. For this reason, various meta-heuristic approaches have emerged to solve these complex models. In this context, the aim of this study is to propose an integrated methodology which seeks an optimum result efficiently regarding a logistics center location selection problem. Thus, the optimal clustering of logistics mobility in a metropolitan area was carried out with GIS and a meta-heuristic approach. GIS produced the spatial information needed by p-median model, then the meta-heuristic approach determined the optimal result that considers the logistics costs. BPSO algorithm has employed as the meta-heuristic and it is observed that the algorithm can reach the optimum results within superior times for the problem sizes tested where binary integer programming verified the optimums and the algorithm continued to reach improved solutions where the exact algorithms failed for larger instances. The integrated solution methodology is applied to a large metropolitan region and it is found that it can be used properly by the urban city planners and supply chain managers to analyze critical nodes of transportation networks of megacities.

Problem of Research: The selection of facility location in the health sector, which stands out with its social benefit dimension mostly, is of great issue for individuals, organizations and the country in general. However, the complex and uncertain structure of health care sector makes this already high-risk, vital, strategic decision-making process even more difficult. Purpose of the Study: The aim of the research is to examine the studies published in facility location selection in health services literature, in terms of methods used. Method: This research is a descriptive research in which the systematic review method and the criterion sampling method were used. Web of Science, Science Direct, Scopus, ProQuest and Google Scholar databases were used to determine the studies whose title has 'hospital' and 'facility location' or 'location selection' or 'site selection' keywords, and which are published in between the years of 2015-2020. After scanning the databases, 2940 results were found. The studies which were Turkish and English, conducted as a research study, and whose full text is available were included. After the exclusion of the studies which doesn't meet the criterias and detailed examination of the remaining studies, 23 studies were included to the research. Findings: It was observed that 65.2% of the studies examined, used MCDM methods in their decision-making processes. 30.4% of the studies have considered the uncertainty factor by applying Gray& Fuzzy Theories. It was seen that 39.15% of the studies aimed to reach the cost minimization as a secondary purpose, and, it was followed by maximum population coverage, and then time-distance minimization. Conclusion: It was observed that most of the studies used MCDM methods, and also have used only one single method. Additionaly, 30,4% of the studies carried out their decision-making processes by taking into account the uncertainty factor.

Multimedia cloud computing has emerged as a popular paradigm for the support of delay-intolerable immersive multimedia applications with high-end three-dimensional rendering. To that end, fog computing offers distributed computational offloading solutions, by positioning rendering servers in close proximity to end users promising in this way continuous service provision, that is otherwise not easily attainable under the strictly centralized cloud-only model. Yet, in order to alleviate the multimedia providers from unnecessary capital expenditure, a strategic placement approach of the servers at the fog layer must be implemented, that can effectively cope both with the network dynamics and the overall imposed deployment cost, and still adhere to the delay bounds set forth by the multimedia application. In this paper, we formally formulate the problem as a facility location problem using constrained optimization over a finite time horizon. We then theoretically analyze the minimum acceptable conditions necessary for a decentralized location of the servers, utilizing solely local information around their immediate neighborhood, that iteratively leads to better solutions. Based on the analysis, we propose a distributed algorithm, namely the Autonomous Renderer Placement Algorithm (ARPA), to address it. ARPA employs localized service relocation to shift the placement according to simple rules that designate elastic migration, replication, and complementary consolidation of the underlying renderers. Simulation results under diversified deployment scenarios, as well as trace-driven comparisons against other approaches, testify to ARPA's accountability in obeying the delay limits and fast converge in finite time slots to a placement solution that both outperforms the baseline alternatives and is close to the optimal one, rendering it suitable for scaling up and down to meet the current demands of the offered multimedia applications.

The objective of this study was to investigate the application of advanced oxidation processes (AOPs) to the treatment of wastewaters contaminated with hydrocarbon oil. Three different oil-contaminated wastewaters were examined and compared: (i) a ‘real’ hydrocarbon wastewater collected from an oil refinery (Conoco-Phillips Whitegate refinery, County Cork, Ireland); (ii) a ‘real’ hydrocarbon wastewater collected from a car-wash facility located at a petroleum filling station; and (iii) a ‘synthetic’ hydrocarbon wastewater generated by emulsifying diesel oil and water. The AOPs investigated were Fe2+/H2O2 (Fenton's reagent), Fe2+/H2O2/UV (Photo-Fenton's reagent) which may be used as an alternative to, or in conjunction with, conventional treatment techniques. Laboratory-scale batch and continuous-flow experiments were undertaken. The photo-Fenton parametric concentrations to maximize COD removal were optimized: pH = 3, H2O2 = 400 mg/L, and Fe2+ = 40 mg/L. In the case of the oil-refinery wastewater, photo-Fenton treatment achieved approximately 50% COD removal and, when preceded by physicochemical treatment, the percentage removal increased to approximately 75%.

In this paper, we propose a simultaneous approach to incorporate inventory control decisions––such as economic order quantity and safety stock decisions––into typical facility location models, which are used to solve the distribution network design problem. A simultaneous model is developed considering a stochastic demand, modeling also the risk pooling phenomenon. We present a non-linear-mixed-integer model and a heuristic solution approach, based on Lagrangian relaxation and the sub-gradient method. In a numerical application, we found that the potential cost reduction, compared to the traditional approach, increases when the holding costs and/or the variability of demand are higher.

This paper presents preference programming technique based multiple criteria decision making analysis for selecting a facility location for a new organization or expansion of an existing facility which is of vital importance for a decision support system and strategic planning process. The implementation of decision support systems is considered crucial to sustain competitive advantage and profitability persistence in turbulent environment. As an effective strategic management and decision making is necessary, multiple criteria decision making analysis supports the decision makers to formulate and implement the right strategy. The investment cost associated with acquiring the property and facility construction makes the facility location selection problem a long-term strategic investment decision, which rationalize the best location selection which results in higher economic benefits through increased productivity and optimal distribution network. Selecting the proper facility location from a given set of alternatives is a difficult task, as many potential qualitative and quantitative multiple conflicting criteria are to be considered. This paper solves a facility location selection problem using preference programming, which is an effective multiple criteria decision making analysis tool applied to deal with complex decision problems in the operational research environment. The ranking results of preference programming are compared with WSM, TOPSIS and VIKOR methods.

Natural gas production from a gas reservoir (Reservoir A) located in the south of Iran, presents solids deposition during processing because the condensate contains suspended and dissolved solids. Solids deposition occurs not only in the transportation lines from the wells to the separators but also in the various operating units of gas streams and condensate stream. In this study, the multisolid-phase model has been used to predict the wax precipitation from gas and gas condensate fluids. The properties of gas and liquid phases are described using the Soave-Redlich-Kwong (SRK) equation of state. The model is then used to predict the possibility of the wax formation in Reservoir A gas facilities, located at the south of Iran. Solid deposition which occurred in the various streams of that facility confirmed the calculated results. Finally, the wax appearance temperature (WAT), the weight percent of wax formation and the effects of pressure and temperature on the wax formation were also predicted.

Location decisions are frequently subject to dynamic aspects such as changes in customer demand. Often, flexibility regarding the geographic location of facilities, as well
as their capacities, is the only solution to such issues. Even when demand can be forecast, finding the optimal schedule for the deployment and dynamic adjustment of capacities remains a challenge. In this thesis, we focus on multi-period facility location problems that allow for dynamic capacity adjustment, in particular those with complex cost structures. We investigate such problems from different Operations Research perspectives, presenting and comparing several mixed-integer programming (MIP) models, assessing their use in practice and developing efficient solution algorithms. The thesis is divided into four parts. We first motivate our research by an industrial
application, in which a logging company needs to locate camps to host the workers involved in forestry operations. We present a MIP model that allows for the construction of additional camps, the expansion and relocation of existing ones, as well as partial closing and reopening of facilities. The model uses particular capacity constraints that involve integer rounding on the left hand side. Economies of scale are considered on several levels of the cost structure. The usefulness of the model is assessed by two case studies. The second part introduces the Dynamic Facility Location Problem with Generalized Modular Capacities (DFLPG). The model generalizes existing formulations for several dynamic
facility location problems and provides stronger linear programming relaxations than the specialized formulations. The model can address facility location problems where the costs for capacity changes are defined for all pairs of capacity levels, as it is the case in the previously introduced industrial problem. It is applied to three special cases: capacity expansion and reduction, temporary facility closing and reopening, and
the combination of both. We prove dominance relationships between our formulation and existing models for the special cases. Computational experiments on a large set of
randomly generated instances with up to 100 facility locations and 1000 customers show that our model can obtain optimal solutions in shorter computing times than the existing
specialized formulations. Given the complexity of such models for large instances, the third part of the thesis proposes efficient Lagrangian heuristics. Based on subgradient
and bundle methods, good quality solutions are found even for large-scale instances with up to 250 facility locations and 1000 customers. To improve the final solution quality, a restricted model is solved based on the information collected through the solution of the Lagrangian dual. Computational results show that the Lagrangian based heuristics provide highly reliable results, producing good quality solutions in short computing times even for instances where generic solvers do not find feasible solutions. Finally, we adapt the Lagrangian heuristics to solve the industrial application. Two different relaxations
are proposed and compared. Extensions of the previous concepts are presented to ensure a reliable solution of the problem, providing high quality solutions in reasonable
computing times.

Location science has a long historical background and the literature of location selection has expanded since it attracts much interest from researchers. As a result of many studies the location science can be classified into several sub-categories; one of which is locating emergency facilities. The determination of locating fire stations is a crucial decision for metropolitans. Reducing response time, maximizing coverage and minimizing the total cost are the most important objectives for selecting the proper location. Using Geographic Information Systems (GIS) is important since it gives an opportunity to study on maps and to have coverage matrices which show the service areas in terms of binary integers and an attractiveness matrix which shows total values of closeness to main roads, residential areas, important buildings and so on. Fire stations have to be located carefully; in an emergency situation the fire department should be able to reach its destination within 5 minutes. Hence, the coverage matrix is very important for defining the potential of alternative locations. Mathematical model is based on the coverage and attractiveness matrices with the objectives of reducing response time, maximizing coverage and the minimizing the total cost. Taking the increasing population and traffic jam and the location in the earthquake zone into consideration, the fire stations have to be found at the most appropriate location in Istanbul to facilitate the arrival at the scene as fast as possible. This paper presents a decision support system approach for locating the fire stations via the geodatabase of Kadikoy district in GIS. In this study, GIS analysis and multi-objective mathematical model were used to consider the opportunities and the threats with strong and weak sides of the possible locations.

This article presents a mixed-integer model to optimize the location of facilities and the underlying transportation network at the same time to minimize the total transportation and operating costs. In this problem, it is assumed that for connecting two nodes, there are several types of links in which their capacity, transportation and construction costs are different. The developed model has various applications in telecommunication, emergency , regional planning, pipeline network, energy management, distribution, to just name a few. To solve the model effectively, this paper also proposes a fix-and-optimize heuristic based on the evolutionary fire-fly algorithm. Finally, to validate the model and evaluate the algorithm's performance, a series of test instances with up to 100 nodes and 600 candidate links with three different levels of quality are reported.

This paper analyses methods used for the evaluation
of sites as part of location strategies for corporations.
Based on the available methods for site selection,
which are pointed out, a comprehensive model for
the analysis of manufacturing sites is developed and
explained in detail. The internationally applicable
model consists of ten phases. The application of
common evaluation methods is explored and
assessed. This paper is complemented by a separate
paper (Part II), which will be published subsequently
and will show the application of the methodology
and prove its practicability through an
international case study. It is the aim of these two
papers to seek understanding of the challenges
attached to site selection processes and, as a result
thereof, achieve substantially improved results from
future site selection projects or location strategies.

... Meysam Alizadeh ... one unit of demand to customer zone i from warehouse at site j, Cjk cost of supplying one unit of demand to warehouse at site j from plant at site k, F r j : fixed cost per unit of time for opening and operating warehouse with capacity level r at site j, Gh k : fixed ...

Purpose – This paper aims to analyze methodological limitations of methods used for the evaluation of sites as part of location strategies for corporations.
Design/methodology/approach – Based on the available methods for site selection, which are pointed out, various challenges for quality- and quantity-related criteria are derived and explained, whereby all common approaches have some methodological deficiencies.
Findings – Those defects have an impact on the result of site selection projects. Therefore, knowledge of these limitations in using certain methods is of essence for the right interpretation of the results. The respective methodological deficiencies are explained and conclusions are drawn.
Research limitations/implications – Research in the area of site selection has been limited mostly to rather comprehensive approaches or national views. A holistic approach toward especially property-related matters is not available in current textbooks.
Originality/value – As common practice proves, the outlined deficiencies are mostly unknown or not considered. It is the aim of this paper to seek understanding of the respective methodological limitations and, as a result thereof, achieve substantially improved results of future site selection projects or location strategies.
Keywords – Management of technology, Property development, Corporate real estate, Industrial engineering, Project and construction management, Operations research, International construction, Industrial facility design, Site selection
Paper type – Conceptual paper

Abstrak Bandar Lampung merupakan salah satu kota besar yang ada di Indonesia yang akan berkembang menjadi kota Metropolitan. Pembangunan insfrastruktur pelayanan public yang baik dapat mempercepat perkembangan sebuah kota. Pengembangan jenis transportasi umum seperti Bus Rapid Transit (BRT) di Kota Bandar Lampung sebagai salah satu moda transportasi yang diharapkan dapat meningkatkan daya tarik masyarakat untuk menggunakan transportasi umum sehingga dapat menekan penggunaan kendaraan pribadi sebagai usaha untuk mengurangi tingkat kemacetan, kesemrawutan dan kecelakaan lalu lintas. Untuk pengoperasian BRT diperlukan adanya fasilitas penunjang, salah satunya adalah halte. Pembangunan halte yang tidak baik akan mengakibatkan bertambahnya permasalahan transportasi, sebab banyak masyarakat yang seharusnya menjadi target pengguna menjadi enggan untuk menggunakan moda ini karena adanya kesulitan disaat akan memanfaatkan fasilitas yang ada. Tujuan dari penelitian ini adalah untuk menentukan jumlah dan lokasi halte di sepanjang rute Rajabasa-Sukaraja Bus Rapid Transit di Kota Bandar Lampung sehingga dapat memberikan akses yang layak ke halte terdekat kepada semua penumpang dengan jumlah halte yang minimum tetapi dapat memenuhi semua titik permintaan di sepanjang rute (coverage area). Dalam penelitian ini, penentuan lokasi dan jumlah halte di sepanjang rute I BRT dilakukan dengan mengidentifikasi lokasi bangkitan yang mempunyai tingkat permintaan relatif tinggi dan kandidat lokasi halte yang memenuhi kriteria. Lokasi halte terpilih ditentukan dengan menggunakan metode Set Covering Problem. Hasil perhitungan menyimpulkan bahwa terdapat 19 lokasi halte terpilih di sepanjang rute. Dalam penelitian ini juga dilakukan analisis penentuan lokasi halte ketika pemerintah memiliki keterbatasan anggaran pembangunan halte. (Kata Kunci : Bus Rapid Transit, Facility Location, Set Covering Problem) Abstract: Bandar Lampung is one of the big cities in Indonesia, which evolves into a Metropolitan city. Infrastructure growth of public services can increase the progression of a city. The development of forms public transportaion such as Bus Rapid Transit (BRT) in Bandar Lampung City as one model of transportation to improves the fascination of public transportation, so that can reduces the personal vehicles uses as an effort to reduces the traffic jam level, dizorganization level and traffic accidents. For the operationalizing of BRT's, it's needs support facilities, one of which is halte. The bad development of halte's can increased the transportation's problem, because the people who become the target users may be lazy to use this model caused by it's difficulties for uses this facilities. The objective of this research was to determine the location and amount of the halte's locations alongside Bus Rapid Transit's routes Rajabasa-Sukaraja in Bandar Lampung City in order to provides the suitable access to the nearest halte for all passengers by the number of the minimum halte's but can fill all demands at alongside routes (coverage area). In this research, the location's determination and amount of the halte alongside Bus Rapid Transit's route Rajabasa-Sukaraja in Bandar Lampung City was conducted by identifying the location's awaken which has the high requested level and fill the criterias of halte's location candidates. The chosen of halte's location is determined by using model Set Covering Problem. The concludes of the result calculation that are 19 halte's locations which chosen by alongside the route. In this research is also conducted by analysist of determination of halte's locations when the government has limited budget in halte's development. (Keyword : Bus Rapid Transit, Facility Location, Set Covering Problem)

U.D Rekayasa Wangdi adalah perusahaan yang bergerak di bidang rekayasa industri mesin yang berlokasi di Cambahan, Nogotirto, Gamping, Sleman, D.I.Yogyakarta.  Perusahaan ini memproduksi berbagai macam mesin dan alat industri untuk skala besar, kecil, menengah dan peralatan. Peneliti melaukan observasi dan wawancara pada UKM tersebut dan diketahui bahwa tata letak yang tersedia belum berdasarkan perhitungan yang baik sehingga laju aliran proses produksi menjadi kurang baik. Peneliti tertarik untuk melakukan riset di UKM ini untuk memberikan usulan tata letak fasilitas berdasarkan produk terlaris yang dibuat pada UKM ini. Metode yang dilakukan peneliti dalam penelitian ini adalah dengan menganalisis struktur produk, proses pembuatan produk, dan menentukan derajat kepentingan dan hubungan dari masing masih departemen menggunakan analisis Activity Relationship Chart, analisis Activity Relationship Diagram, dan analisis Area Allocation Diagram. Selanjutnya menganalisis ongkos yang timbul dari material handling dan memberikan usulan tata letak fasilitas yang lebih baik. Biaya yang timbul dari tata letak fasilitas lebih mengarah pada biaya material handling dimana ketika menggunakan tata letak awal biaya yang dibutuhkan adalah Rp28.125,00. Perhitungan usulan tata letak fasilitas yang diusulkan oleh peneliti membutuhkan biaya material handling sebesar Rp11.538,00, selisih biaya tata letak awal dengan tata letak usulan adalah Rp16.587,00.
Kata Kunci : Tata Letak Fasilitas, Kerangka, Mesin Pengaduk Adonan Batako, material handling