This paper presents a framework for reducing the energy consumption of embedded real-time systems. We implemented the presented framework as both an optimization tookchain and an energy-aware real-time operating system. The framework consists of the integration of multiple techniques to optimize the energy consumption. The main idea behind our approach is to utilize trade-offs between the energy consumption and the performance of different processor configurations during task checkpoints, and to maintain memory allocation during task context switches. In our framework, a target application is statically analyzed at both intra-task and inter-task levels. Based on these analyzed results, run-time optimization is performed in response to the behavior of the application. A case study shows that our toolchain and real-time operating systems have achieved energy reduction while satisfying the real-time performance. The toolchain has also been successfully applied to a practical application.

A dynamic energy performance scaling (DEPS) framework had been proposed as a generalization of the dynamic voltage frequency scaling (DVFS). In this paper, we propose a scheme of checkpoint selection for DEPS framework. The checkpoint is a inserted function call in a program for switching the hardware configurations. Our scheme of checkpoint selection judges energy efficiency of a checkpoint set using intra-task analysis informations. This information is called the DEPS profile. It consists of sets of hardware configurations, execution time and energy consumption of a task. Our scheme evaluates DEPS profiles related with different checkpoint sets, and determines which checkpoint set is the most energy efficient. To achieve this goal, we also propose a quantitative evaluation method of the DEPS profile. This method enables us to judge which DEPS profile is the most energy efficient. From experimental results, we confirm the reasonability of our quantitative evaluation, and that our scheme can select the optimal checkpoint set in realistic time.

A dynamic energy performance scaling (DEPS) framework has been proposed as a generalization of dynamic voltage frequency scaling (DVFS). The DEPS framework selects an energy-optimal hardware configuration at runtime. To reduce runtime overhead, Pareto-optimal combinations of hardware configurations should be provided via DEPS profiling during the design phase. The challenge of DEPS profiling lies in extracting the Pareto-optimal combinations efficiently from the exponential search space. We propose two exact algorithms to reduce the number of calculations in DEPS profiling. These algorithms can be used with common search algorithms. We also propose a heuristic algorithm for searching Pareto-optimal configurations efficiently. Extensive experiments are performed, and they demonstrate that the proposed algorithms can complete DEPS profiling within a reasonable amount of time and generate optimal DEPS profiles. It is believed that the proposed algorithms will enable easy application of the DEPS framework in practice.

We propose a novel method to generate partial products for reduced area parallel multipliers. Our method reduces the total number of partial product bits of parallel multiplication by about half. We call partial products generated by our method Compound Partial Products (CPPs). Each CPP has four candidate values: zero, a part of the multiplicand, a part of the multiplier and a part of the sum of the operands. Our method selects one from the four candidates according to a pair of a multiplicand bit and a multiplier bit. Multipliers employing the CPPs are approximately 30% smaller than array multipliers without radix-4 Booth's method, and approximately up to 10% smaller than array multipliers with radix-4 Booth's method. We also propose an acceleration method of the multipliers using CPPs.

This paper presents a framework for the purpose of energy optimization of embedded real-time systems. We implemented the presented framework as an optimization toolchain and an energy-aware real-time operating system. Our framework is synthetic, that is, multiple techniques optimize the target application together. The main idea of our approach is to utilize a trade-off between energy and performance of the processor configuration. The optimal processor configuration is selected at each appropriate point in the task. Additionally, an optimization technique about the memory allocation is employed in our framework. Our framework is also gradual, that is, the target application is optimized in a step-by-step manner. The characteristic and the behavior of target applications are analyzed and optimized for both intra-task and inter-task levels by our toolchain at the static time. Based on the results of static time optimization, the runtime energy optimization is performed by a real-time operating system according to the behavior of the application. A case study shows that energy minimization is achieved on average while keeping the real-time performance.

BACKGROUNDAn increase in cytosolic protein phosphatases (PPs) de-phosphorylates phospholamban, decreasing the Ca(2+) uptake of the sarcoplasmic reticulum (SR). The effects of PP inhibitors on cellular Ca(2+) handling were investigated.METHODS AND RESULTSTwitch Ca(2+) transients (CaTs) and cell shortening were measured in intact rat cardiac myocytes, and caffeine-induced Ca(2+) transients (CaffCaTs) and Ca(2+) sparks were studied in saponin-permeabilized cells. Calyculin A augmented isoproterenol-induced increases in CaTs and cell shortening without altering the diastolic [Ca(2+)](i) and twitch [Ca(2+)](i) decay. The protein kinase A catalytic subunit (PKA(cat)) increased the peak of CaffCaTs between 5 and 50 U/ml, and the addition of inhibitor-1 (I-1) augmented the increase. PKA(cat) increased Ca(2+) spark frequency and the addition of I-1 increased it further. PKA(cat) at 50 U/ml amplified the peak and prolonged the duration of Ca(2+) sparks, whereas the addition of I-1 did not alter them. An abrupt inhibition of SR Ca(2+) uptake following exposure to PKA(cat) caused a gradual decrease in Ca(2+) spark frequency, but the addition of I-1 did not accelerate the decline of Ca(2+) spark frequency or CaffCaTs.CONCLUSIONSInhibition of PPs augmented the inotropic effect of isoproterenol. Specific inhibition of PP1 could stimulate the Ca(2+) uptake of the SR with less significant effects on the Ca(2+) release.

The present study investigates the enrichment of anaerobic ammonium oxidation (anammox) bacteria in the marine environment using sediment samples obtained from a sea-based waste disposal site and discusses the construction of marine anammox bioreactor. Enrichment of bacteria related to Candidatus Scalindua wagneri along with simultaneous removal of nitrite and ammonium ions was observed in the continuous bioreactor culture under a total nitrogen loading rate of 0.4 kg-N m(-3) day(-1).

Calmodulin (CaM) and Ca2+/CaM-dependent protein kinase II (CaMKII) play important roles in the development of heart failure. In this study, we evaluated the effects of CaM on mitochondrial membrane potential (ΔΨm), permeability transition pore (mPTP) and the production of reactive oxygen species (ROS) in permeabilized myocytes; our findings are as follows. (1) CaM depolarized ΔΨm dose-dependently, but this was prevented by an inhibitor of CaM (W-7) or CaMKII (autocamtide 2-related inhibitory peptide (AIP)). (2) CaM accelerated calcein leakage from mitochondria, indicating the opening of mPTP, however this was prevented by AIP. (3) Cyclosporin A (an inhibitor of the mPTP) inhibited both CaM-induced ΔΨm depolarization and calcein leakage. (4) CaM increased mitochondrial ROS, which was related to ΔΨm depolarization and the opening of mPTP. (5) Chelating of cytosolic Ca2+ by BAPTA, the depletion of SR Ca2+ by thapsigargin (an inhibitor of SERCA) and the inhibition of mitochondrial Ca2+ uniporter by Ru360 attenuated the effects of CaM on mitochondrial function. (6) CaM accelerated Ca2+ extrusion from mitochondria. We conclude that CaM/CaMKII depolarized ΔΨm and opened mPTP by increasing ROS production, and these effects were strictly regulated by the local increase in cytosolic Ca2+ concentration, initiated by Ca2+ releases from the SR. In addition, CaM was involved in the regulation of mitochondrial Ca2+ homeostasis.

あらまし Karatsubaアルゴリズムに基づく小面積乗算器を提案する.Karatsubaアルゴリズムはソフトウェ アで多倍長乗算を効率良く行うアルゴリズムである.Karatsuba アルゴリズムを並列乗算器に適用した場合,必 要な論理素子数は少ないが,配線が複雑になる.そのため,従来は Karatsuba アルゴリズムは並列乗算器には 向かないと考えられてきた.VLSI において使用できる配線層数が増加しており,配線が回路面積に及ぼす影響 が小さくなっている.そのため,必要な論理素子数が少なくなる構成法を選択することで,小面積の回路を構成 できると考えられる.Karatsuba アルゴリズムに基づく並列乗算器を設計したところ,配列型乗算器よりも小面 積であった.更に,内部の計算順序を変更することによって必要な論理素子数を削減し,けた上げ伝搬加算器を 削減することによって高速化した.これらの手法を適用することにより,回路面積,遅延時間の両方で改善が見 られた. キーワード 小面積乗算器,Karatsuba アルゴリズム,配線層

Background: The protein phosphatase inhibitor-1 (I-1) is a potent and specific inhibitor of protein phosphatase 1 only when it was phosphorylated by protein kinase A (PKA). The reduced I-1 activity has been implicated in the impaired excitation–contraction coupling in heart failure. However, the precise effects of I-1 on the SR Ca2+ handling remain undefined.