Bertha Maya Sopha

Urban distribution center location: Combination of spatial analysis and multi-objective mixed-integer linear programming

Location of urban distribution center (UDC) has played an important role in reducing distribution cost, environmental impact, and traffic congestion in urban areas. The article aims at evaluating potential location of UDC for sugar commodity using a combined approach that comprises two stages: spatial analysis and multi-objective mixed-integer linear programming. Results demonstrate that different locations of UDC correspond to different costs and environmental implications. It is suggested that a new UDC for the sugar commodity can be located at the east part of the city outskirt. Using more than two UDCs in the studied case appears to be not economically and environmentally beneficial.

Comparison study of metaheuristics: Empirical application of delivery problems

Many existing studies have used hypothetical data to evaluate the performance of various metaheuristics in solving delivery route optimization. As empirical data impose characteristics of a particular problem, it is necessary to evaluate whether the problem characteristics may influence to the performance of metaheuristics. This article therefore attempts to compare the performance of metaheuristics, that is, genetic algorithm, ant colony optimization (ACO), particle swarm optimization, and simulated annealing (SA), to solve an empirical delivery problem in Yogyakarta, Indonesia. Two cases are developed to capture different characteristics of empirical data. The first case introduces delivery problem of one logistics operator and 58 retailers; the second case presents collaborative strategy in delivery problem, involving two logistics operators and 142 retailers. Results indicate that ACO and SA perform better with respect to less distance traveled for both cases and higher truck utility and lower number of routes for the second case.

Collaborative distribution - application to the city of Yogyakarta, Indonesia

Increasing of population leads to escalation of demand needs which results in busier logistics activities. Collaborative strategy has become an alternative to manage these activities, depending on the conditions in a certain location. This paper applied collaborative distribution model to Yogyakarta city, in order to see whether the collaboration is beneficial. The performance of collaborative distribution model is limited to the efficiency of capital and transportation cost based on optimum routing selection. In general, collaborative strategy showed more savings in total cost than that for the non-collaborative one. However, building and land investment should be an important consideration especially if collaborative strategy requires distribution centers expansion.

Beyond Climatic Variation: Human Disturbances Alter the Effectiveness of a Protected Area to Reduce Fires in Tropical Peatlands of Sumatra, Indonesia

The occurrence of fires has frequently been used to highlight environmental hazards at regional and global scale, and as a proxy for the effectiveness of protected areas. In contrast, the mechanism behind wildfire dynamics in tropical peat land protected areas had been poorly addressed thus far. Our study provides a novel application of assessing fire patterns from a tropical peatland protected area and surrounding landscape. We investigated the importance of both climatic factors (top-down mechanism) and human interventions (bottom-up mechanism) on fire occurrences through analyzing 15-year (2001 - 2015) LANDSAT and MODIS images of the Padang Sugihan Wildlife Reserve (PSWR). Fire density along side road and canal construction were analyzed jointly together with the monthly and annual precipitation, and evidences of climatic anomalies. The reserve was effective in limiting fire occurrences from surrounding landscapes only in wet years. We revealed that peat fire patterns in the protected area and the landscape matrix emerged beyond climatic factors, and the distance from canal system could explain the fire occurrences. Our results show that it is essential to address processes at a landscape level, particularly at the surroundings of the reserve, in order to increase the effectiveness of fire protection, including the development of fire-prone classes maps.