Published papers

低ジッタと高スケジュール可能性を達成するために，準固定優先度スケジューリングを提案する．

準固定優先度スケジューリング向けリアルタイムオペレーティングシステムRT-Estを提案する．

This paper presents an algorithm, called Earliest Deadline Critical Laxity (EDCL), for scheduling sporadic task systems on multiprocessors.

固定優先度マルチプロセッサスケジューリングを対象として，プロセッサの消費電力量を効果的に削減する動的電圧周波数制御アルゴリズムを提案する．

優先度付きSMTアーキテクチャにおいて変動する実行時間をハードウェアにより安定化することを目的としてIPC制御機構を設計・実装する．

最高優先度以外のスレッドで実行するタスクの付加部分の実行割合を向上させるために，RMWPを拡張したResponsive RMWP（R-RMWP）を提案する．

三次元実装の手法であるFFCSP(Flexible carrier Folded real Chip Size Package)を用い,非常に高集積でDRAMを内蔵する高信頼超小型SiPを開発する手法を提案する.

In the past decade, real-Time systems (RTSs), which must maintain time constraints to avoid catastrophic consequences, have been widely introduced into various embedded systems and Internet of Things (IoTs). The RTSs are required to be energy efficient as they are used in embedded devices in which battery life is important. In this study, we investigated the RTS energy efficiency by analyzing the ability of body bias (BB) in providing a satisfying tradeoff between performance and energy. We propose a practical and realistic model that includes the BB energy and timing overhead in addition to idle region analysis. This study was conducted using accurate parameters extracted from a real chip using silicon on thin box (SOTB) technology. By using the BB control based on the proposed model, about 34% energy reduction was achieved.

It is essential for any embedded systems and increasing popularity of Internet of Things (IoT) be energy efficient. Such systems tend to work intermittently and reducing leakage in the idle time is essential. Energy reduction techniques bring the system to a low power mode which also provokes transition overheads. If such overheads are not considered, the task may not be schedulable under a given deadline. To get a gain in energy savings, the idle state must be longer than a minimum required time. This time is referred as Break Even Time (BET). To properly design efficient algorithms and schedulers we must calculate and include the BET. In this paper, we present the first studies to examine the BET using accurate parameters extracted from a real chip using Silicon On Thin Box (SOTB) technology employing Body Bias Control (BB) energy saving technique. In this study, we demonstrate the BET range for SOTB microcontrollers, on the order of 0.5ms up to 1ms.

This paper addresses the problem of finding, evaluating, and selecting the best set of codewords for the 4b/10b line code, a dependable line code with forward error correction (FEC) designed for real-time communication. Based on the results of our scheme [1], we formulate codeword search as an instance of the maximum clique problem, and enumerate all candidate codeword sets via maximum clique enumeration as proposed by Eblen et al. [2]. We then measure each set in terms of resistance to bit errors caused by noise and present a canonical set of codewords for the 4b/10b line code. Additionally, we show that maximum clique enumeration is #P-hard.