Next-Generation Environment-Aware Cellular Networks: Modern Green Techniques and Implementation Challenges

Over the last decade, mobile communications have been witnessing a noteworthy increase of data traffic demand that is causing an enormous energy consumption in cellular networks. The reduction of their fossil fuel consumption in addition to the huge energy bills paid by mobile operators is considered as the most important challenges for the next-generation cellular networks. Although most of the proposed studies were focusing on individual physical layer power optimizations, there is a growing necessity to meet the green objective of fifth-generation cellular networks while respecting the user's quality of service. This paper investigates four important techniques that could be exploited separately or together in order to enable wireless operators achieve

Hydrogeochemical quality and suitability studies of groundwater in northern Bangladesh

Agriculture, rapid urbanization and geochemical processes have direct or indirect effects on the chemical composition of groundwater and aquifer geochemistry. Hydro-chemical investigations, which are significant for assessment of water quality, were carried out to study the sources of dissolved ions in groundwater of Dinajpur district, northern Bangladesh. The groundwater samplish were analyzed for physico-chemical properties like pH, electrical conductance, hardness, alkalinity, total dissolved solids and Ca2+, Mg2+, Na+, K+, C032', HC03", SO,2 and CI" ions, respectively. Based on the analyses, certain parameters like sodium adsorption ratio, soluble sodium percentage, potential salinity, residual sodium carbonate, Kelly's ratio, permeability index and Gibbs ratio were also calculated. The results showed that the groundwater of study area was fresh, slightly acidic (pH 5.3-6.4) and low in TDS (35-275 mg I"1). Ground water of the study area was found suitable for irrigation, drinking and domestic purposes, since most of the parameters analyzed were within the WHO recommended values for drinking water. High concentration of N03" and CI' was reported in areas with extensive agriculture and rapid urbanization. Ion-exchange, weathering, oxidation and dissolution of minerals were major geochemical processes governing the groundwater evolution in study area. Gibb's diagram showed that all the samples fell in the rock dominance field. Based on evaluation, it is clear that groundwater quality of the study area was suitable for both domestic and irrigation purposes

Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

Contains fulltext : 172380.pdf (publisher's version ) (Open Access

Energy efficiency and nutrient removal performance: comparison between several types of activated sludge process

The operation of a wastewater treatment plant entails a huge amount of electricity. The majority of energy inputs are consumed by aeration systems to support biological processes for treated wastewater. Urban wastewater treatment plants are energy-intensive facilities that consume significant amounts of energy. For conventional activated sludge systems, 25% to 60% of the operating costs are associated with energy use. Malaysia's wastewater treatment plants have fallen short in terms of technological advancement in the sewerage industry. The goal of this research is to analyse and make a comparison of the capabilities of the sequencing batch reactor (SBR) and other activated sludge (AS) system treatment plants in Selangor, Malaysia. High energy electricity consumption was an important issue that affected the operational cost and development of wastewater treatment plants (WWTP). The result and discussion for the analysis had been presented into comparison result for each objective of this research studied which was to determine lowest energy efficiency, to assess highest nutrient removal efficiency and compliance rate for each WWTP process plant. This paper presents best practices that can be implemented and adapted by operators in their pursuit of energy and reduce cost or expenses in the sewage treatment plant

MODEL PENENTUAN UKURAN LOT PRODUKSI DENGAN POLA PERMINTAAN BERFLUKTUASI

The purpose of this paper is to examine the impact of varying demand on the production lot size and the schedule of delivery in the integrated inventory system. This system is consisted of a single manufacturer as the supplier and a single buyer. Mostly, the problems on the economic lot size model are assumed that demand is continuous with time. Actually, demand occurs are varying in time rather than continuously over the planning time horizon. In this case, the buyer has decided the amount of order for each period is varied, because of the changing market environment. The integrated inventory system model between a supplier and a buyer are developed and implemented under the condition with varied demand. Forward dynamic programming is implemented for searching the solution. The objective is to minimize the total cost, associated with a single product for a deterministic varying demand. Two conditions are examined here, i.e., the integrated model with uncapacitated and capacitated production system. The difference between these two models is in the constraints formulation. The capacity constraints will give higher total cost, especially if the setup cost higher than the holding cost. A numerical example is presented to illustrate the implementation of the solution algorithm. Abstract in Bahasa Indonesia: Pada makalah ini diteliti pengaruh permintaan yang berfluktuasi terhadap penentuan ukuran lot produksi dan jadwal pengiriman pada sistem persediaan terintegrasi, dengan total ongkos persediaan melibatkan sistem persediaan pemanufaktur dan pembeli secara bersama. Sistem terdiri atas pemanufaktur tunggal dan pembeli tunggal untuk pemesanan satu jenis produk.Umumnya permasalahan penentuan ukuran lot produksi memiliki asumsi bahwa permintaan bersifat kontinu terhadap waktu. Penentuan ukuran lot pada model integrasi sistem persediaan antara pemanufaktur dan pembeli dengan kondisi permintaan berfluktuatif bertujuan meminimasi total ongkos. Pencarian solusi penentuan ukuran lot produksi dengan permintaan berfluktuatif mempergunakan pendekatan forward dynamic programming. Adapun model integrasi yang dikemukakan mempertimbangkan dua kondisi, yaitu kondisi kapasitas produksi tidak terbatas dan kapasitas produksi terbatas. Perbedaan formulasi terletak pada kondisi pembatas yang digunakan. Hasil pengamatan menunjukkan bahwa apabila ongkos setup jauh lebih tinggi dari pada ongkos simpan, maka kondisi dengan mempertimbangkan kapasitas akan menghasilkan total ongkos yang lebih tinggi. Suatu contoh numerik diberikan sebagai ilustrasi dari algoritma yang diusulkan. Kata kunci: ukuran lot produksi, fluktuasi permintaan, jadwal pengiriman, integrasi pemanufaktur-pembeli, programa dinamis

MODEL PENJADWALAN BATCH PADA SATU MESIN YANG MENGALAMI DETERIORASI UNTUK MINIMASI TOTAL BIAYA SIMPAN DAN BIAYA KUALITAS

This research discusses batch scheduling model accommodating the condition of machine deterioration. The proposed model has changed the formulation of quality cost from that discussed in Indrapriyatna et al. (2007a), especially in the internal and external failure costs. It is assumed that the distribution of time between out-of-control conditions follows the exponential distribution. An algorithm has been proposed. This research concludes that, for continue batch size, the greater the sample size proportion of the batch size, the greater the total cost and number of batches. In addition, the greater the probability of producing nonconforming products, the greater the total cost. For any values of the probability, the number of batches will be the same, but the batch sizes are different. On the other hand, for model with discrete batch sizes, we used Indrapriyatna et al. (2007b) approach to solve the problem. Abstract in Bahasa Indonesia: Penelitian ini membahas model penjadwalan batch yang mengakomodasikan kondisi mesin terdeteriorasi, yang akan menyebabkan produk menjadi nonconforming. Pengembangan ini mengubah formulasi biaya kualitas yang telah dirumuskan pada model Indrapriyatna et al. (2007a), khususnya untuk Biaya Kegagalan Internal dan Biaya Kegagalan Eksternal. Dalam model usulan, waktu antar kondisi out-of-control diasumsikan berdistribusi eksponensial. Sebuah algoritma penyelesaian dirancang untuk model usulan tersebut. Studi ini menunjukkan bahwa, untuk model dengan ukuran batch kontinu, semakin besar proporsi ukuran sampel menyebabkan biaya total dan jumlah batch yang semakin besar. Selain itu, semakin besar peluang produk nonconforming dihasilkan maka akan menyebabkan semakin besar total biaya. Observasi lain menunjukkan bahwa jumlah batch selalu sama untuk sebarang nilai peluang; walaupun ukuran masing-masing batch berbeda. Pada model dengan ukuran batch diskrit digunakan 3 buah metode untuk mengubah ukuran batch menjadi integer yang diusulkan oleh Indrapriyatna et al. (2007b) dan menghasilkan kesimpulan yang sama. Kata kunci: mesin terdeteriorasi, produk nonconforming, ukuran batch kontinu, ukuran batch diskrit

Geochemical assessment of groundwater composition and evaluating its suitability of Saidpur Upazilla in Bangladesh

The chemical analysis of 44 groundwater samples in the northern Bangladesh has been evaluated to determine the hydrogeochemical processes and major ions, heavy and rare metal concentration for its suitability for agricultural and domestic purposes. The quality analysis is performed through the estimation of pH, EC, cations (Ca2+, Mg2+, Na+ , K+ , Zn2+, Cu2+, Mn2+, Fe3+ and As3+), anions (CO3 2-, HCO3 - , NO3 - , SO4 2-, PO4 3- and Cl- ) and TDS (total dissolved solids). We also computed several variables such as SAR (sodium adsorption ratio), SSP (soluble sodium percentage) RSC (residual sodium carbonate), potential salinity, permeability index, Kelly's ratio, Gibbs ratio and hardness to evaluate the suitability of groundwater supply for specific uses. From the geochemical results, it has been found that both the cations and anions varied in the groundwater. Among the chemical budget of ions, magnesium and chloride were found to be the most predominant ions. The intense agricultural activities may be an important factor for the higher concentration of nitrates in these aquifers. Based on the total hardness, most groundwaters are moderately hard. According to EC and SAR the most dominant class is C1-S1. The major ion concentrations are below the acceptable level for drinking water. The salinity hazard is low thus, there is less chances to increase of toxic salt concentrations. Gibbs diagram indicates that all the samples fall in the precipitation dominance field. Regarding cation and anion constituents, groundwater is suitable for irrigation and drinking purposes except of few wells