Compiler compatible 5.66 Mb/mm2 8T 1R1W register file in 14 nm FinFET technology

1-read/1-write (1R1W) register file (RF) is a popular memory configuration in modern feature rich SoCs requiring significant amount of embedded memory. A memory compiler is constructed using the 8T RF bitcell spanning a range of instances from 32 b to 72 Kb. An 8T low-leakage bitcell of 0.106 μm² is used in a 14 nm FinFET technology with a 70 nm contacted gate pitch for high-density (HD) two-port (TP) RF memory compiler which achieves 5.66 Mb/mm² array density for a 72 Kb array which is the highest reported density in 14 nm FinFET technology. The density improvement is achieved by using techniques such as leaf-cell optimization (eliminating transistors), better architectural planning, top level connectivity through leaf-cell abutment and minimizing the number of unique leaf-cells. These techniques are fully compatible with memory compiler usage over the required span. Leakage power is minimized by using power-switches without degrading the density mentioned above. Self-induced supply voltage collapse technique is applied for write and a four stack static keeper is used for read Vmin improvement. Fabricated test chips using 14 nm process have demonstrated 2.33 GHz performance at 1.1 V/25 °C operation. Overall V_min of 550 mV is achieved with this design at 25 °C. The inbuilt power-switch improves leakage power by 12x in simulation. Approximately 8% die area of a leading 14 nm SoC in commercialization is occupied by these compiled RF instances.     

Microbiological water quality in urban coastal beaches: the influence of water dynamics and optimization of the sampling strategy

In the summer 2001, the microbiological water quality of two contiguous urban coastal beaches (Porto, Portugal) was surveyed for 18 consecutive days. The sampling strategy consisted in sampling surface water in early morning, noon and afternoon. A total of 184 samples were processed at Pastoras beach, a confined area between two jetties, and Ourigo Beach more open to the ocean. At the first beach site, all samples exceeded fecal contamination above guide values (GV) and 82.6% above mandatory values (MV) set out in the EU Bathing Water Directive; whereas at Pastoras Beach, the figures were 93.5% for GV and 26.1% for MV, showing a potential health risk. The periodicity of fecal indicators in raw sewage, the tidal status and wind conditions dramatically influenced the water quality. The quality decreased in the morning regardless of tide conditions, but improved subsequently during the day, particularly during high tide and under the influence of afternoon NW winds. These dynamics are incompatible with the fortnight routine sampling according to the recommendations of the EU Bathing Water Directive, and the strategy should be revised on a beach-to-beach basis, having in mind the profile for the coastal zone.     

The water quality of the River Thame in the Thames Basin of south/south-eastern England

The water quality of the River Thame, a tributary of the River Thames in the Thames basin, is described in relation to point and diffuse contaminant inputs and runoff from permeable and impermeable bedrock geology with their own characteristic water quality. The data is examined to see if the market town of Aylesbury in the upper part of the catchment influences water quality. Previous studies highlighted the influence of Aylesbury sewage treatment works (STW) on soluble reactive phosphorus (SRP) concentrations in the river before and after phosphorus (P) stripping at the STW. Variations in water quality along the river are described and the study indicates that, apart from SRP, water quality determinants seem to be relatively unaffected by Aylesbury. The Thame water quality is compared with other catchment typologies and it is very similar to that of the main stem of the Thames even though the Thames is mainly Chalk groundwater fed. Differences in water quality largely link to the amount of STW effluent within the rivers and to the endmember compositions of the groundwater and near surface water sources.     

基于GCC的TMS320C67xx汇编代码的优化

为了使生成的汇编代码具有更高的执行效率,设计并实现了一种基于GCC的 TMS320C67xx汇编指令级的代码优化算法。首先,将汇编指令按照功能划分为不同的指令类型,并将汇编指令链接到链表中。然后,针对每一个寄存器建立对该寄存器的读写操作指令链表。最后,通过对指令类型的判断和对寄存器读写操作指令链表的分析,完成了冗余代码的删除和指令合并。实验结果表明,经过代码优化后,TMS320C67xx汇编代码的执行效率提高了20％左右,较中间代码级的优化算法执行效率提高了15％左右。     

Seasonal Water Level Manipulation for Flood Risk Management Influences Home‐Range Size of Common Bream Abramis brama L. in a Lowland River

The increased threat of flooding from climate change requires ever greater management of rivers to alleviate flood risk. Although the impacts of river modification on fish communities are well documented, the effects of river management practices on fish behaviour have received relatively little attention. Here, a long‐term (4 years) acoustic telemetry study was used to analyse the spatial–temporal behaviour of common bream in a lowland river system (River Witham, Lincolnshire, UK) in which water levels are artificially manipulated biannually as part of a flood storage strategy. Levels are lowered in the autumn and increased again in the spring, to increase in‐river winter flood storage capacity. Home‐range size varied according to season, with home ranges being larger in the spring and summer months in comparison with those recorded during the autumn and winter months. When water levels within the river system were artificially manipulated, the bream responded by altering their home‐range size, increasing it after the levels had been raised and reducing it following the lowering of the river levels. This is in contrast to the cumulative overall distances bream were recorded to travel, which were unaffected by water level manipulation, suggesting water level manipulation did not affect activity levels. Although such changes in behaviour do not necessarily equate to a negative impact on fitness, reduced home‐range size brought about by water level manipulation does have implications for habitat availability and the number of competitive, predatory and parasitic interactions encountered. Copyright © 2013 John Wiley & Sons, Ltd.     

Syntax and semantics of universal programming languages

This paper deals with certain characterizations of the sets of positive integers which when represented as strings on a finite alphabet, form tree adjunct languages, As the context free languages constitute a subfamily of tree adjunct languages, the results carry over to the former as well.     

A self‐applicable online partial evaluator for recursive flowchart languages

This paper describes a self‐applicable online partial evaluator for a flowchart language with recursive calls. Self‐application of the partial evaluator yields generating extensions that are as efficient as those reported in the literature for offline partial evaluation. This result is remarkable because it has been assumed that online partial evaluation techniques unavoidably lead to inefficient and overgeneralized generating extensions. The purpose of this paper is not to determine which kind of partial evaluation is better, but to show how the problem can be solved by recursive polyvariant specialization. The design of the self‐applicable online partial evaluator is based on a number of known techniques, but by combining them in a new way this result can be produced. The partial evaluator, its techniques, and its implementation are presented in full. Self‐application according to all three Futamura projections is demonstrated. The complete bootstrap of a compiler generator from a partial evaluator is also reported. Copyright © 2011 John Wiley & Sons, Ltd.     

A register window scheduling method for prolog

Abstract

This paper describes a windowed register file management technique for Prolog that we call “SORWT'’ (Splittable Overlapped Register Window Technique). This scheme is implemented in our Prolog system. Two pointers, the CWP (Current Window Pointer) and TWP (Top Window Pointer), are used with the register file so that the environment, choice point and arguments can be stored in register windows. This greatly reduces the number of memory accesses and procedure call/return overhead. This paper describes in detail how Warren instructions can be implemented in a windowed register file system. A mapping function between register windows and memory window areas and register file overflow/underflow handling algorithms are also presented. In addition, to cope with argument overflow problems in a window, the concept of extended windows is proposed.

Thirty benchmark programs are used to study the following effects: performance issue of SORW versus conventional stacked register windows; optimal register file and window sizes; argument overflow rate; and the efficiency of extended windows.     

Relations among Security Models for Authenticated Key Exchange

Usually, key‐establishment protocols are suggested in a security model. However, there exist several different security models in the literature defined by their respective security notions. In this paper, we study the relations between the security models of key establishment. For the chosen security models, we first show that some proven key‐establishment protocols are not secure in the more restricted security models. We then suggest two compilers by which we can convert a key‐establishment protocol that is secure in a specific security model into a key‐establishment protocol that is still secure in a more restricted security model.     

Welfare Improvisation from the Receiving Waters of Urban Wastewater Systems in the Context of the Water Framework Directive

The compliance of wastewater authorities with the Water Framework Directive (WFD, 2000/60/EC) although may highly contribute to a “good” ecological status in aquatic ecosystems, is alleged to require disproportionally high costs in relevance to the anticipated benefits. This is mainly due to the limited yet research in the assessment of the economic welfare derived by the compliance with the WFD. In this light, the direct and indirect economic benefits emerged by the attaining of WFD are investigated. The wastewater treatment plant of Athens (Greece) is demonstrated as a comprehensive pilot case.