We give an efficient polynomial-time approximation scheme (EPTAS) for the Joint Replenishment Problem (JRP) with stationary demand. Moreover, using a similar technique, we give a PTAS for the capacitated JRP with non-stationary demand but constant size capaci-

Demand for business intelligence solutions continues to grow in the industry at record rates to combat competitive pressures and to attain business agility. Still organizations continue to struggle on how to implement successful business intelligence solutions. Despite its growing popularity and maturity as a field, it appears that organizations follow key guidelines that ensure the failure of ...

A pilot scale wastewater treatment plant was designed, constructed and operated on site to treat wastewater from a combined effluent drain. The activated sludge process (ASP) was used at three different hydraulic retention times (HRT) of 12, 10 and 8 hrs at an average MLSS concentration of 3500 mg/L. Under each HRT, the pilot plant was operated for a period of 10-12 weeks. Chemical oxygen deman...

The efforts of modern civilization to create an environment to meet human aspirations have successfully resulted in constant improvements of our lifestyle, but it has increased risks to human and ecological health. This situation has motivated many scientists throughout the world to analyze the environmental factors that can affect our health or ecology and to calculate the levels of risk. In B...

Anaerobic modeling is a useful tool to describe and simulate the condition and behaviour of anaerobic treatment units for better effluent quality and biogas generation. The present investigation deals with the anaerobic treatment of brewery wastewater with varying organic loads. The chemical oxygen demand (COD) and total suspended solids (TSS) of the influent and effluent of the bioreactor were...

Without significant intervention, demand for crude oil could rise by a further 25% by 2035, stemming from its use for transportation, particularly road transport. Many technologies for alternative fuels and substitute transport energy carriers are being researched, but successful implementation of these technologies at scale will require attention to consumer-behavioural and policy challenges a...

In this paper, we give the rst constant-approximations for a number of layered network design problems. We begin by modeling hierarchical caching, where caches are placed in layers and each layer satis es a xed percentage of the demand (bounded miss rates). We present a constant approximation to the minimum total cost of placing the caches and routing demand through the layers. We extend this m...