The complexity of makespan minimization for pipeline transportation

The complexity of makespan minimization for pipeline transportation

SPTP is a model for the pipeline transportation of petroleum products. It uses a directed graph G, where arcs represent pipes and nodes represent locations. In this paper, we analyze the complexity of 4nding a minimum makespan solution to SPTP. This problem is called SPTMP. We prove that, for any 4xed ¿ 0, there is no 1− -approximate algorithm for the SPTMP unless P=NP, where is the input size....

Makespan minimization for flow-shop problems with transportation times and a single robot

In a ow-shop problem with transportation times and a single robot n jobs consisting of m operations have to be processed in the same order on m machines. Additionally, transportation times are considered if a job changes from one machine to another. We assume that suucient buuer space exists between the machines and all transportations have to be done by a single robot. The objective is to dete...

the effect of task complexity on lexical complexity and grammatical accuracy of efl learners’ argumentative writing

بر اساس فرضیه شناخت رابینسون (2001 و 2003 و 2005) و مدل ظرفیت توجه محدود اسکهان (1998)، این تحقیق تاثیر پیچیدگی تکلیف را بر پیچیدگی واژگان و صحت گرامری نوشتار مباحثه ای 60 نفر از دانشجویان زبان انگلیسی بررسی کرد. میزان پیچیدگی تکلیف از طریق فاکتورهای پراکندگی-منابع تعیین شد. همه ی شرکت کنندگان به صورت نیمه تصادفی به یکی از سه گروه: (1) گروه موضوع، (2) گروه موضوع + اندیشه و (3) گروه موضوع + اندی...

study of cohesive devices in the textbook of english for the students of apsychology by rastegarpour

this study investigates the cohesive devices used in the textbook of english for the students of psychology. the research questions and hypotheses in the present study are based on what frequency and distribution of grammatical and lexical cohesive devices are. then, to answer the questions all grammatical and lexical cohesive devices in reading comprehension passages from 6 units of 21units th...

Priority algorithms for makespan minimization in the subset model