مکان‌یابی مراکز شبکه خدمات مشاوره‌ای، فنی و مهندسی کشاورزی با استفاده از مدل مکان‌یابی پوشش بیشینه

نتایج تحقیقات مختلف در بخش خدمات نشان داده است که تامین مطلوب خدمات عامل مهمی در افزایش بهره‌وری زنجیره تامین کشاورزی است. در این پژوهش بخشی از الزامات استقرار شبکه خدمات مشاوره‌ای، فنی و مهندسی کشاورزی در بخش کشاورزی که مربوط به مکان این مراکز است مورد بررسی قرارگرفته است. مکان‌یابی این مراکز از طریق تعیین حیطه عمل و استقرار مناسب شرکت‌های خدمات مشاوره‌ای، فنی و مهندسی کشاورزی بر اساس ظرفیت‌های منطقه‌ای و با در نظر گرفتن فاصله انواع مشتریان این‌گونه مراکز انجام‌شده است. در این مطالعه از مدل مکان‌یابی پوشش بیشینه استفاده‌شده است که توسط نرم‌افزار cplex و الگوریتم شاخه و حد حل‌شده است. در این پژوهش به‌منظور نشان دادن قابلیت‌های عملی روش‌ها و مدل‌های توسعه داده‌شده، یک مطالعه موردی دریکی از شهرستان‌های استان همدان انجام‌شده است. به‌منظور یافتن شعاع پوشش کامل در هریک از دهستان‌های موردمطالعه، شعاع‌های پوشش مختلف آزمون شد. بدین منظور از شعاع پنج تا 160 کیلومتر مورد بررسی قرار گرفت. نتایج نشان داد که در برخی شعاع‌های پوشش، نه‌تنها مکان بهینه تغییر نمی‌کند، بلکه تعداد نقاط پوشش داده‌شده نیز ثابت است. هم‌چنین نتایج مدل حاکی از آن است که شعاع پوشش به‌منظور پوشش کامل مزارع متقاضی دریافت خدمات کشاورزی در هر دهستان متفاوت است به‌طوری‌که بیش‌ترین میزان 20 کیلومتر در دهستان درجزین علیا و کم‌ترین میزان 10 کیلومتر در دهستان سردرود سفلی است. در هر شعاع پوشش، مکانی که با استفاده از مدل پوشش بیشینه انتخاب شده قادر است بیش‌ترین تعداد نقاط تقاضا را تحت پوشش قرار دهد، زیرا در تابع هدف این مدل، بیشینه‌سازی بر اساس تعداد مشتریان انجام شده است.

Locating Advisory and Agricultural Engineering Service Network using Set Covering Model

<p > <strong >Introduction </strong > </p > <p >In this research, a part of the requirements for the establishment of a network of consultancy, agricultural engineering and technical services in the agricultural sector, which is related to the location of these centers, has been reviewed. The location of these centers has been done through the determination of the field of operation and the appropriate establishment of consulting, engineering, and agricultural consulting companies based on regional capacities and taking into account the distance between the types of customers of such centers. </p > <p >   </p > <p > <strong >Materials and Methods </strong > </p > <p >In the issue of locating service centers three main types of customer can be classified. Firstclass customers, which have the largest number among different types of customers, are farms and units that produce agricultural products. Each point of demand for these categories of customers may require different types of services at different times. Due to the large number and dispersion, these category of customers are considered as a focal point for ease of modeling in rural areas where they are located. Also, due to various reasons, including access to various facilities, security, traffic congestion and etc., the nominations for deployment of service centers are also considered in the same rural areas. In order to transport agricultural products from the place of production, the current location is considered to be the distance from the manufacturer 's place, and the destination of the product is not studied in this issue. Second and thirdtype customers are demanding access to services at their own place. These types of customers may exist in some areas and agricultural supply chains. These two groups of customers include refineries, warehouses and silos mainly operating in the postharvest of agricultural production. To meet the demand for each of the different demand points of different types of customers, the number of different trips from service centers to customer premises or vice versa is required. Each service center does not offer the same type of service to its customers. A total of 127 service packages are available for provision at a service center. </p > <p >   </p > <p > <strong >Results and Discussion </strong > </p > <p >The main basis for choosing the optimal location for covering models is the placement of demand points in the defined coverage radius for the candidate points. Different radius were tested to find the perfect coverage radius in each of the studied villages. For this purpose, a radius of five to 160 kilometers was examined. In some coverage radius, not only does the optimal location not change, but the number of served points is also fixed. The location of different types of customers is different, so that the first type of customers are fully located in the village, but second and third type customers are widespread in the Hamedan province. </p > <p >   </p > <p > <strong >Conclusions </strong > </p > <p >To conclude, it is necessary to consider the demand of customers located in the further distances of the service center due to the nature of the agricultural service, which requires inevitable traffic over long distances, when adjusting the operational plans of the agricultural service centers. To provide sufficient justification for the distance, though within the radius of coverage. Thus, the results of this research show that if all service centers cover 130 kilometers of radius, the largest number of customers will be covered. It should be noted that for the full coverage of all customers, the coverage radius of the service centers varies, but with the same radius, the 130 km radius is the largest coverage of the agricultural service centers in the Razan city. </p >