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Papers by Candra Bachtiyar

Research paper thumbnail of A Simulated Annealing Heuristic for the Capacitated Green Vehicle Routing Problem

Mathematical Problems in Engineering, Jan 13, 2019

This research studies the capacitated green vehicle routing problem (CGVRP), which is an extensio... more This research studies the capacitated green vehicle routing problem (CGVRP), which is an extension of the green vehicle routing problem (GVRP), characterized by the purpose of harmonizing environmental and economic costs by implementing effective routes to meet any environmental concerns while fulfilling customer demand. We formulate the mathematical model of the CGVRP and propose a simulated annealing (SA) heuristic for its solution in which the CGVRP is set up as a mixed integer linear program (MILP). The objective of the CGVRP is to minimize the total distance traveled by an alternative fuel vehicle (AFV). This research conducts a numerical experiment and sensitivity analysis. The results of the numerical experiment show that the SA algorithm is capable of obtaining good CGVRP solutions within a reasonable amount of time, and the sensitivity analysis demonstrates that the total distance is dependent on the number of customers and the vehicle driving range.

Research paper thumbnail of A simulated annealing heuristic for the capacitated location routing problem

Computers & Industrial Engineering, 2010

The location routing problem (LRP) is a relatively new research direction within location analysi... more The location routing problem (LRP) is a relatively new research direction within location analysis that takes into account vehicle routing aspects. The goal of LRP is to solve a facility location problem and a vehicle routing problem simultaneously. We propose a simulated annealing (SA) based heuristic for solving the LRP. The proposed SALRP heuristic is tested on three sets of well-known benchmark instances and the results are compared with other heuristics in the literature. The computational study indicates that the proposed SALRP heuristic is competitive with other well-known algorithms.

Research paper thumbnail of Setting Parameter Mesin Press Dengan Metode Respon Permukaan Pada Pabrik Kelapa Sawit

Parameter kontrol yang harus dijaga pada mesin press adalah biji pecah (broken nut) dengan nilai ... more Parameter kontrol yang harus dijaga pada mesin press adalah biji pecah (broken nut) dengan nilai standard maksimal 18% dan kehilangan minyak dalam serabut (oil losses in fibre/oil dry) dengan nilai standard adalah 6,8-7,5%. Penelitian ini menggunakan metode respon permukaan sebagai alat untuk menentukan kondisi operasi optimum mesin press dengan parameter temperatur digester dan tekanan hidraulik. Temperatur digester divariasikan pada 93, 98, 103 0 C dan tekanan hidrolik divariasikan pada 30, 40, 50 bar untuk percobaan orde pertama dan menggunakan skema central composite design (CCD) pada percobaan orde kedua. Hasil penelitian menunjukkan temperatur digester dan tekanan hidrolik berpengaruh terhadap kualitas parameter yang dikontrol. Model yang dihasilkan untuk biji pecah adalah b Yˆ = 275,397-6,059 1 X + 1,847 2 X + 0,033 2 1 X-0,003 2 2 X-0,014 1 X 2 X dan untuk kehilangan minyak dalam serabut adalah o Yˆ = 237,337-4,431 1 X-0,814 2 X + 0,022 2 1 X + 0,002 2 2 X + 0,006 1 X 2 X. Parameter optimal mesin press diperoleh pada saat temperatur digester 96,9 0 C dan tekanan hidraulik 39,3 bar dengan respon broken nut sebesar 13,75% dengan nilai desirability 0,70916 dan oil dry sebesar 7,01% dengan nilai desirability 0,9883. Kata kunci: Metode respon permukaan, biji pecah, kerugian minyak, temperatur digester, tekanan hidraulik

Research paper thumbnail of A Simulated Annealing Heuristic for the Capacitated Green Vehicle Routing Problem

Mathematical Problems in Engineering, Jan 13, 2019

This research studies the capacitated green vehicle routing problem (CGVRP), which is an extensio... more This research studies the capacitated green vehicle routing problem (CGVRP), which is an extension of the green vehicle routing problem (GVRP), characterized by the purpose of harmonizing environmental and economic costs by implementing effective routes to meet any environmental concerns while fulfilling customer demand. We formulate the mathematical model of the CGVRP and propose a simulated annealing (SA) heuristic for its solution in which the CGVRP is set up as a mixed integer linear program (MILP). The objective of the CGVRP is to minimize the total distance traveled by an alternative fuel vehicle (AFV). This research conducts a numerical experiment and sensitivity analysis. The results of the numerical experiment show that the SA algorithm is capable of obtaining good CGVRP solutions within a reasonable amount of time, and the sensitivity analysis demonstrates that the total distance is dependent on the number of customers and the vehicle driving range.

Research paper thumbnail of A simulated annealing heuristic for the capacitated location routing problem

Computers & Industrial Engineering, 2010

The location routing problem (LRP) is a relatively new research direction within location analysi... more The location routing problem (LRP) is a relatively new research direction within location analysis that takes into account vehicle routing aspects. The goal of LRP is to solve a facility location problem and a vehicle routing problem simultaneously. We propose a simulated annealing (SA) based heuristic for solving the LRP. The proposed SALRP heuristic is tested on three sets of well-known benchmark instances and the results are compared with other heuristics in the literature. The computational study indicates that the proposed SALRP heuristic is competitive with other well-known algorithms.

Research paper thumbnail of Setting Parameter Mesin Press Dengan Metode Respon Permukaan Pada Pabrik Kelapa Sawit

Parameter kontrol yang harus dijaga pada mesin press adalah biji pecah (broken nut) dengan nilai ... more Parameter kontrol yang harus dijaga pada mesin press adalah biji pecah (broken nut) dengan nilai standard maksimal 18% dan kehilangan minyak dalam serabut (oil losses in fibre/oil dry) dengan nilai standard adalah 6,8-7,5%. Penelitian ini menggunakan metode respon permukaan sebagai alat untuk menentukan kondisi operasi optimum mesin press dengan parameter temperatur digester dan tekanan hidraulik. Temperatur digester divariasikan pada 93, 98, 103 0 C dan tekanan hidrolik divariasikan pada 30, 40, 50 bar untuk percobaan orde pertama dan menggunakan skema central composite design (CCD) pada percobaan orde kedua. Hasil penelitian menunjukkan temperatur digester dan tekanan hidrolik berpengaruh terhadap kualitas parameter yang dikontrol. Model yang dihasilkan untuk biji pecah adalah b Yˆ = 275,397-6,059 1 X + 1,847 2 X + 0,033 2 1 X-0,003 2 2 X-0,014 1 X 2 X dan untuk kehilangan minyak dalam serabut adalah o Yˆ = 237,337-4,431 1 X-0,814 2 X + 0,022 2 1 X + 0,002 2 2 X + 0,006 1 X 2 X. Parameter optimal mesin press diperoleh pada saat temperatur digester 96,9 0 C dan tekanan hidraulik 39,3 bar dengan respon broken nut sebesar 13,75% dengan nilai desirability 0,70916 dan oil dry sebesar 7,01% dengan nilai desirability 0,9883. Kata kunci: Metode respon permukaan, biji pecah, kerugian minyak, temperatur digester, tekanan hidraulik