Integrated Urban Lei River (North Pakistan) Water Resources Management

The urban Lei river consists of a catchment area of about 211 km 2 . About 55% lies in Islamabad (population about 3 million) and the rest in Rawalpindi (population about 3 million). The city of Islamabad is growing without considering its hydrogeological set-up, which is creating further flood problems in Rawalpindi. Even after the drought of 1994, groundwater is being privately exploited without any central legal control. Measures for increasing the amount of available groundwater would improve drinking water both qualitatively and quantitatively, reduce loss through uncontrolled runoff, reduce aquifer depletion and lead also to improved monitoring. The chessboard regional city planning of Islamabad, as laid down in the Master Plan (1960), has to be replanned inter-disciplinary according to topographical, geological, meteorological, hydrological and hydrogeological investigations. Sustainable ecological solutions ought not be sacrificed to political short-sighted expedience.     

Thermoeconomic considerations in the design and rating of two-phase heat exchangers

We discuss a closed-form model for thermoeconomic design and analysis of two-phase heat exchangers used as condensers and evaporators. The results are presented in terms of the optimum number of heat-transfer units (NTUs) as a function of the dimensionless unit-cost ratio and the exit-to-inlet absolute temperature ratio of the single-phase fluid. The sensitivities of various unit-cost parameters (UCPs) are presented. It is demonstrated that the selection of UCPs play a significant role in sizing heat exchangers.     

Comparison of Performance of Packet Scheduling Algorithms in LTE-A HetNets

The concept of usage of heterogeneous networks (HetNets) is about improving the LTE system performance by increasing the capacity and coverage of the Macro cell. In this paper, a performance comparison of various packet scheduling algorithms such as Proportional Fair, Maximum Largest Weighted Delay First and Exponential/Proportional Fair is studied in detail in the HetNets environment. The key performance indicators such as throughput, packet loss ratio, delay and fairness are considered to judge the performance of the scheduling algorithms. Various strategies such as increasing the number of Pico cells in the cell edge were used in the simulation for the performance evaluation study. The results achieved through various simulations show that adding Pico cells to the existing Macros enhances the overall system performance in addition to the various scheduling algorithms implemented in Macros. For reader’s convenience, various types of graphs have been used to represent the simulation results to better understand the performance metrics of various scheduling algorithms. Simulation results shows that overall system gain has increased because of adding Picos and thereby providing better coverage in the cell edge areas and thereby increasing the capacity of the network to provide better quality of service.     

Correction to: Similar Feed-forward Loop Crosstalk Patterns may Impact Robust Information Transport Across E. coli and S. Cerevisiae Transcriptional Networks

Mobile Networks and Applications - The original version of this article unfortunately contained a mistake in the author group section. Author Preetam Ghosh’s given name was incorrectly...     

An overview of state of the art and research in the fields of sensible, latent and thermo-chemical thermal energy storage

Due to the increase in volatile renewable power and heat generation (wind or solar), thermal energy storage (TES) has obtained growing importance and interest. The technology can be distinguished into three main types: sensible, latent and thermochemical storage. Apart from low and medium temperature heat applications, high temperature TES also is an attractive means to store power in the form of heat (before the thermodynamic transformation process). Thermochemical storage allows for long duration seasonal storage of energy.     

直觉线性μ-演算中的合成推理

讨论了以基于前缀封闭集合的Heyting代数的直觉解释的线性μ-演算(IμTL)作为描述“假设-保证”的逻辑基础的问题,提出了一个基于IμTL的“假设-保证”规则.该规则比往常应用线性时序逻辑(LTL)作为规范语言的那些规则具有更好的表达能力,扩展了对形如“always ?”等安全性质的“假设-保证”的范围,具备更一般的“假设-保证”推理能力及对循环推理的支持.     

Comparison of Conventional and Cross-Layer Multimedia Transport Schemes for Wireless Networks

Three competing schemes have been proposed for multimedia transport over broadband wireless channels: (a) traditional UDP (Postel, The User Datagram Protocol, 1980 [1]), (b) semi-cross-layer UDP-Lite (The Lightweight User Datagram Protocol, 2004 [2]), and (c) cross-layer header estimation (Khayam et al., IEEE Transactions on Multimedia 9(2):377–385, 2007 [3]; Khayam and Radha, IEEE Transactions on Wireless Communications 6(11):3946–3954, 2007 [4]). In all these schemes, corrupted and lost packets are recovered using FEC at the application layer. In this paper, we analytically and experimentally compare the performances of these broadband wireless multimedia schemes. First, we derive lower bounds on the excepted FEC redundancy required by ideal cross-layer header estimation, UDP and UDP-Lite over an arbitrary-order Markov wireless channel. We show that under realistic wireless channel conditions, the cross-layer header estimation scheme always requires lesser redundancy than UDP and UDP-Lite. We then propose a practical minimum distance decoding (MDD) header estimation scheme, which is receiver-based, low complexity and highly accurate. Trace-driven multimedia experiments over wireless LANs demonstrate that MDD header estimation requires significantly lesser FEC redundancy and renders better video quality than existing schemes.