Efficient Algorithms for a Large-Scale Supplier Selection and Order Allocation Problem Considering Carbon Emissions and Quantity Discounts

This paper considers a multi-period supplier selection and order allocation problem for a green supply chain system that consists of a single buyer and multiple heterogeneous suppliers. The buyer sells multiple products to end customers and periodically replenishes each item’s inventory using a periodic inventory control policy. The periodic inventory control policy used by the buyer starts every period with an order size determination of each item and the subsequent supplier selection to fulfill the orders. Because each supplier in the system is different from other suppliers in the types of carrying items, delivery distance, item price, and quantity discount schedule, the buyer’s problem becomes a complicated optimization problem. For the described order size and supplier selection problem of the buyer, we propose a nonlinear integer programming model and develop two different algorithms to enhance the usability of the model in a real business environment with a large amount of data. The algorithms are developed to considerably cut computational time and at the same time to generate a good feasible solution to a given supplier selection and order allocation problem. Computational experiments that were conducted to test the efficiency of the algorithms showed that they can cut as much as 99% of the computational time and successfully find feasible solutions, deviating not more than 3.4% from the optimal solutions.

Kajian Geografis Dan Faktor-Faktor Yang Mempengaruhi Masyarakat Berbelanja Di Pasar Pagi Kecamatan Padang Barat

Abstrak Penelitian ini bertujuan untuk mengetahui kajian geografis dan faktor-faktor yang mempengaruhi masyarakat untuk berbelanja ke pasar pagi kecamatan padang barat. jenis penelitian yakni deskriptif kualitatif. Informan penelitiannya adalah pembeli dan pedagang pasar pagi kecamatan padang barat. sedangkan pendekatan yang dilakukan dalam pengambilan informan adalah dengan teknik aksidental. Teknik pengumpulan data adalah observasi, wawancara dan dokumentasi. Teknik analisis data adalah reduksi, penyajian data, dan kesimpulan. Adapun hasil penelitian sebagai berikut: 1) Pasar Pagi Kecamatan Padang Barat berada pada letak yang strategis di tinjau dari kedekatannya dengan permukiman penduduk,dan mudah untuk dijangkau oleh layanan transportasi 2) faktor-faktor yang mempengaruhi pembeli berbelanja ke Pasar Pagi Kecamatan Padang Barat Kota Padang adalah aksesibilitas, kelengkapan barang, harga barang, waktu dan jarak tempuh,kualitas barang. Kata kunci : Faktor Penarik, Letak Strategis, Pasar The aims of this study to find out how geographical studies and factors that influence people to shop in the Pasar Pagi District of Padang Barat.The research type is descriptive qualitative The research informants are buyers and traders in the western Padang district market. while the approach taken in taking informants is accidental techniques. Data collection techniques are observation, interview, and documentation. Data collection techniques are observation, interview, and documentation. Data analysis techniques are data reduction, data presentation, conclusion. The research results are as follows: 1) Pasar Pagi District of Padang Barat is located in a strategic location in terms of its proximity to residential areas, and is easy to reach by transportation services 2) factors that influence shoppers shopping at Pasar Pagi, Padang Barat Subdistrict, Padang City are accessibility, completeness, item price, time and distance, quality of goods. Keywords: Pulling Factor, Strategic Location, Market

Atopic Dermatitis: Perspectives and Attitudes of Adult Patients and Affected Child Caregivers Assessed by Focus Group

Introduction: Important dimensions such as personal experiences, attitudes toward disease, its causes and treatments, are not fully addressed in clinical trials. Focus group (FG) has emerged as an interesting and valuable tool in clinical research complementing this gap. The aim of this qualitative research was to assess in both caregivers and patients dealing with atopic dermatitis (AD) their attitudes, personal experiences and perspectives toward the disease and its topical treatment as well as the impact in quality of life (QoL).Material and Methods: For discussion sessions, 10 caregivers of children and 10 adult patients were recruited. Two sessions of FG took place with 3 main themes discussed: perspectives toward AD, topical treatments and the impact in QoL. All activities were recorded in video and the discussions and notes were then transcribed to a document, followed by transcripts analysis.Results: The best descriptive feelings in the moment of diagnosis where “concern” (30%) and “quality of life” (30%) for caregivers and patients, respectively. The actual “positive” emotion or state of mind toward the disease was “overcoming” for caregivers (21%) and “control” for patients (17%). The main “negative or neutral” emotion was “fear” for caregivers (13%) and “resignation” for patients (18%), but when projecting to their child, “frustration” (19%) was the most mentioned. In relation to topical treatments, the mean global satisfaction of caregivers was high for tacrolimus (8.5/10), except in the item “price”. In the case of patients, corticosteroids received a better score (8.0/10), with exception for “tolerability/adverse effects”. Features like “preventive treatment with reduction of flares” and “free of cortisone” were important for both participants in an “ideal topical medicine” setting. All participants showed high levels of negative impact in their QoL due to AD, with 47% and 64.6% considering scores of “very much” and “a lot” of interference, respectively.Conclusion: Qualitative studies in AD by FG are scarce and to our knowledge this is the first one gathering both adult patients and caregivers. The dimensions yielded by this approach are useful to complement data retrieved from clinical trials and to drive decisions from researchers and health authorities.

PENERAPAN JARINGAN SARAF TIRUAN STANDARISASI HARGA BARANG DISTRIBUTOR DI MEDAN DENGAN ALGORITMA LAVENBERG MARQUARDT

The Medan Central Bureau of Statistics is tasked with surveying data or calculating quality statistical data and information which includes accuracy of relevance and also for price standardization or determination. The problem in setting the price standard is because many companies raise prices without surveying data first and some other companies do not adjust the price of one to another. To handle this, one method is needed to study and analyze Distributor Item Price data to be uniform, using knowledge of artificial neural network analysis using the Levenberg-Marquardt method. With this activity the Medan Central Bureau of Statistics hopes that the company in an effort to increase customer satisfaction with the products produced can be done by producing a product or item with high quality and quality with balanced pricing in accordance with the conditions in the market (adjusted to community income). The results obtained through this study are the uniformity of the prices of distributor goods in the market, which have previously been through the process of testing and applying mathematically statistically using matlab software.Keywords: Artificial Neural Networks, Levenberg-Marquardt Method, Distributor Prices, MATLAB

Do Latino and non-Latino grocery stores differ in the availability and affordability of healthy food items in a low-income, metropolitan region?

ObjectiveTo compare non-ethnically based supermarkets and Latino grocery stores (tiendas) in a lower-income region with regard to the availability, quality and cost of several healthy v. unhealthy food items.DesignA cross-sectional study conducted by three independent observers to audit twenty-five grocery stores identified as the main source of groceries for 80 % of Latino families enrolled in a childhood obesity study. Stores were classified as supermarkets and tiendas on the basis of key characteristics.SettingSouth San Diego County.SubjectsTen tiendas and fifteen supermarkets.ResultsTiendas were smaller than supermarkets (five v. twelve aisles, P = 0·003). Availability of fresh produce did not differ by store type; quality differed for one fruit item. Price per unit (pound or piece) was lower in tiendas for most fresh produce. The cost of meeting the US Department of Agriculture's recommended weekly servings of produce based on an 8368 kJ (2000 kcal)/d diet was $US 3·00 lower in tiendas compared with supermarkets (P < 0·001). The cost of 1 gallon of skimmed milk was significantly higher in tiendas ($US 3·29 v. $US 2·69; P = 0·005) and lean (7 % fat) ground beef was available in only one tienda (10 %) compared with ten (67 %) supermarkets (P = 0·01).ConclusionsBarriers remain in the ability to purchase healthier dairy and meat options in tiendas; the same is not true for produce. These results highlight the potential that tiendas have in improving access to quality, fresh produce within lower-income communities. However, efforts are needed to increase the access and affordability of healthy dairy and meat products.

I Scratched Yours: The Prevalence of Reciprocation in Feedback Provision on eBay

Many online systems for bilateral transactions elicit performance feedback from both transacting partners. Such bilateral feedback giving introduces strategic considerations. We focus on reciprocity in the giving of feedback: how prevalent a strategy of giving feedback is only if feedback is first received from one's trading partner. The overall level of feedback activity clearly depends on the prevalence of the reciprocation strategy: in a market with many reciprocators and few unconditional feedback providers, the equilibrium quantity of feedback can be quite low. We estimate the prevalence of such reciprocation in one market, eBay. Reciprocation cannot be directly distinguished from late feedback that was not conditioned on the partner having provided feedback. We develop a model that distinguishes the two by exploiting information about the timing of feedback provision when the partner does not provide feedback. We find that buyers and sellers on eBay used the “reciprocate only” strategy about 20-23% of the time. We also measure the extent to which the prevalence of these strategies changes with the experience levels of the two parties and with the item price.