Power consumption of CMOS digital logic designs has increased rapidly for the last several years. It has become an important issue, not only in battery-powered applications, but also in high-performance digital designs because of packaging and cooling requirements. At multi-GHz clock rates in use today, charging and discharging CMOS gates and wires, especially in clocks with their relatively large capacitances, leads to significant power consumption. Recovering and recycling the stored charge or energy about to be lost when these nodes are discharged to ground is a potentially good strategy that must be explored for use in future energy-efficient design methodologies. This dissertation investigates a number of novel clock energy recycling techniques to improve the overall power dissipation of high-performance logic circuits. If efficient recycling energy of the clock network can be demonstrated, it might be used in many high-performance chip designs, to lower power and save energy. A number of chip prototypes were designed and constructed to demonstrate that this energy can be successfully recycled or recovered in different ways: • Recycling clock network energy by supplying a secondary DC-DC power converter: the output of this power converter can be used to supply another region of the chip, thereby avoiding the need to draw additional energy from the primary supply. One test chip demonstrates energy in the final clock load can be recycled, while another demonstrates that clock distribution energy can be recycled. • Recovering clock network energy and returning it back to the power grid: each clock cycle, a portion of the energy just drawn from the supply is transferred back at the end of the cycle, effectively reducing the power consumption of the clock network. The recycling methods described in this thesis are able to preserve the more ideal square clock shape which has been a limitation of previous work in this area. Overall, the results provided in this thesis demonstrate that energy recycling is very promising and must be pursued in a number of other areas of the chip in order to obtain an energy-efficient design.

This dissertation presents a novel satellite timekeeping system which does not require on-board atomic clocks as used by existing navigation satellite systems such as GPS, GLONASS or the planned GALILEO system. This concept is differentiated by the employment of a synchronization framework combined with lightweight steerable on-board clocks which act as transponders re-broadcasting the precise time remotely provided by the time synchronization network located on the ground. This allows the system to operate optimally when satellites are in direct contact with the ground station, making it suitable for a system like the Japanese Quasi-Zenith Satellite System, QZSS. Low satellite mass and low satellite manufacturing and launch cost are significant advantages of this novel system. Two possible implementations of the time synchronization network for QZSS are presented. Additionally, the problem of satellite communication interruption is analyzed and a solution is presented. Finally a positioning and timing quality analysis, aimed to provide understanding of the actual timing quality requirements for QZSS, is presented.

This thesis focuses on molecular characterization of circadian clock genes in insects. It explores genetic diversity of circadian clock genes by molecular characterization of several insect species including two dipteran flies (Musca domestica and Drosophila melanogaster), two cockroach species representing ancestral insects, and the linden bug, Pyrrhocoris apterus. Furthermore it considers various roles of circadian clock genes in insect physiology. Application of molecular-biology methods in Pyrrhocoris apterus, non-model insect species, enable us to investigate involvement of circadian clock genes in photoperiod induced physiological responses. Application of molecular-biology methods in Periplaneta americana and Blattella germanica was used to explore involvement of circadian clock genes in magnetoreception.

Photoperiodism is the ability of plants and animals to utilize day length or night length to mitigate seasonal exigencies. The circadian clock allows organisms to organize daily demands. Both process are set by light, and for more than 80 years a functional relationship has been pursued. Previous experiments have revealed, through phenotypic expression, that the daily circadian clock and seasonal photoperiodic timer have evolved independently, yet molecular evidence is lacking. Herein, we use the mosquito, Wyeomyia smithii, to understand the relationship between the photoperiodic response, diapause, and the daily circadian clock. We measured variation in the formal properties of the core circadian clock over a latitudinal and altitudinal gradient which we compare to the critical photoperiod, a measure of diapause, over the same geographic gradient. We found that there is no correlation with any of the formal properties of the core circadian clock and critical photoperiod, indicating independent evolution.

Understanding the dynamical bases of the interaction between the plant mineral nutrition and the circadian clock could contribute to improve crop yield and resistance to adverse conditions, such as mineral element deficiencies. Magnesium is an essential element that catalyzes more than six hundred enzymatic reactions and occupies the center of the chlorophyll structure in plants. Physiological targets of magnesium deficiency are generally better described in aerial than in belowground organs. In this thesis, we first characterized the root morphology of the model species Arabidopsis thaliana (Columbia-0) in response to magnesium supply during in vitro culture. The length of primary root and the number and length of lateral roots decreased during magnesium depletion. A local magnesium-rich source does not enhance the root foraging capacity, unlike some other major nutrients. Auxin and abscisic acid emerged as two hormones shaping root morphology in response to magnesium deficiency. Second, we investigated the natural variation of the root morphology response to magnesium supply in Arabidopsis. Thirty-six accessions were screened in vitro. Compared to the reference Columbia-0, some accessions had higher number and length of lateral roots at low magnesium supply. Root or shoot magnesium concentrations did not implicitly correlate with the root morphological traits. However, shoot calcium and root phosphorus concentrations correlated positively with the lateral root number and length, while root iron negatively with the length of primary root. Third, we focused on the interaction between the plant magnesium nutrition and the circadian clock circuit. We tested for a possible involvement of PHYTOCHROME INTERACTING FACTOR 3-LIKE 1 (PIL1) - a clock-associated gene that is down-regulated during magnesium depletion - in morphological and physiological responses, and for a circadian connection of PIL1 in the context of magnesium deficiency. The phenotypes of loss-of-function and overexpression lines did not reveal a major role of PIL1 in the magnesium deficiency symptom manifestation but rather in the plant mineral profile. The expression of PIL1 was apparently not under any circadian control. However, PIL1 seemed to regulate the expressions of some core clock genes (CCA1, LHY and PRR9), which were also targets during magnesium deficiency. In conclusion, PIL1 has a link with the circadian rhythm machinery but it does not emerge as a pivotal regulator of magnesium stress responses. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Power consumption of CMOS digital logic designs has increased rapidly for the last several years. It has become an important issue, not only in battery-powered applications, but also in high-performance digital designs because of packaging and cooling requirements. At multi-GHz clock rates in use today, charging and discharging CMOS gates and wires, especially in clocks with their relatively large capacitances, leads to significant power consumption. Recovering and recycling the stored charge or energy about to be lost when these nodes are discharged to ground is a potentially good strategy that must be explored for use in future energy-efficient design methodologies. This dissertation investigates a number of novel clock energy recycling techniques to improve the overall power dissipation of high-performance logic circuits. If efficient recycling energy of the clock network can be demonstrated, it might be used in many high-performance chip designs, to lower power and save energy. A number of chip prototypes were designed and constructed to demonstrate that this energy can be successfully recycled or recovered in different ways: • Recycling clock network energy by supplying a secondary DC-DC power converter: the output of this power converter can be used to supply another region of the chip, thereby avoiding the need to draw additional energy from the primary supply. One test chip demonstrates energy in the final clock load can be recycled, while another demonstrates that clock distribution energy can be recycled. • Recovering clock network energy and returning it back to the power grid: each clock cycle, a portion of the energy just drawn from the supply is transferred back at the end of the cycle, effectively reducing the power consumption of the clock network. The recycling methods described in this thesis are able to preserve the more ideal square clock shape which has been a limitation of previous work in this area. Overall, the results provided in this thesis demonstrate that energy recycling is very promising and must be pursued in a number of other areas of the chip in order to obtain an energy-efficient design. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

京都大学 / 0048 / 新制・課程博士 / 博士(薬科学) / 甲第21717号 / 薬科博第108号 / 新制||薬科||12(附属図書館) / 京都大学大学院薬学研究科医薬創成情報科学専攻 / (主査)教授 土居 雅夫, 教授 竹島 浩, 教授 中山 和久 / 学位規則第4条第1項該当 / Doctor of Pharmaceutical Sciences / Kyoto University / DGAM

Clock multipliers are among the most critical elements in high speed digital circuits. Power consumption, area, jitter and wide tuning range are key design metrics in these circuits. To provide a wide range of clock frequencies, Digitally Controlled Ring Oscillators (DCROs), whose frequencies are discretely tuned using a Frequency Code Word (FCW), have been investigated in recent studies. They have several advantages over LC-based Voltage Controlled Oscillators (VCO) including simplicity of design, small die area (i.e. no large inductors), better compatibility with deep submicron CMOS processes,ability to offer multiple output phases, and wider tuning range.A compact differential Injection Locked Clock Multiplier (ILCM) based on an injection locked DCRO is implemented in this thesis. As the transistor features continuously shrink and the supply voltage is reduced, ILCMs are becoming more prone to issues such as increased effect of random mismatch, increased device noise, susceptibility of the design to noise coupling and vulnerability to Process Voltage and Temperature (PVT) variations. Furthermore, ILCMs in recent System on a Chip (SoCs) have stringent design requirements including accurate frequency tuning, fine fractional resolution, high levels of integration and better amenability to technology scaling. In the proposed ILCM, multiple techniques were used to address deep submicron CMOS design challenges, as well as modern applications’ requirements. The design is fully digital, synthesizable and automatically placed and routed. All circuit blocks were implemented using digital design flow and designed using a Hardware Description Language (HDL). This allows the design to be more easily ported to deep submicron processes. Online or offline PVT calibration can be performed using a replica oscillator and high speed digital counters to track frequency drifts with PVT variations. A DCRO based on a matrix structure has been utilized to reduce period variations due to random mismatch. The DCRO is built up from pseudo differential delay cells to enhance design immunity to noise coupling. The key thesis contributions are implementing a new DCRO structure using fully syntheziable differential structure, utilizing a novel PVT calibrator that can compensate for frequency mismatch between the main DCRO and its replica, and using a low complexity fractional ILCM technique that achieves a fine fractional resolution with few number of ring oscillator stages.Designed in a TSMC 65 nm GP CMOS process with no analog or RF enhancements, the proposed ILCM frequency ranges from 1.0 to 1.8 GHz and occupies 124:5 m 170 m of chip area. The ILCM can operate in integer or fractional mode for multiplication ratios up to 9. At 1.7 GHz and 1.1 V, the measured integrated RMS jitter (1 kHz to 30 MHz) for the 3rd and 9th multiplication factors are 197 fs and 381 fs, respectively. The ILCM consumes 13.25 mW of power and has a fraction resolution of fref=32. Furthermore, it achieves a jitter-power FOM of −241 dB, when measured at room temperature and 1.1 V. When tested in the presence of switching noise, it provides up to 7 dB improvement in phase noise when compared to a single ended version of the ILCM. In the presence of voltage variations (from 0.9 V to 1.1 V) and temperature variations (from 30 C to 70 C), the maximum integrated RMS jitter variation observed was 50 fs.

Internal clocks, or circadian rhythms, are nearly ubiquitous across taxa (e.g., animals, plants, fungi, and cyanobacteria), and it is widely believed that a biological clock benefits organisms by enabling them to schedule behavioral and physiological changes in anticipation of predictable changes in environmental conditions. Theory and evidence suggest it is important that the internal clock resonate closely with the 24-h daily cycle. Recently, however, Cyclosa turbinata (Walckenaer, 1841) (Araneidae) was revealed to have a circadian clock with a period of about 19 h, which was presumed to be anomalous. Here, we report on the behavioral rhythms of a nocturnal orbweaver, Metazygia wittfeldae (McCook, 1894), from the same family. Under laboratory conditions of a 12:12 h light:dark cycle, we found that locomotor activity initiates shortly after dark, reaching a peak early in the dark phase, continuing at a lower level throughout the remaining dark phase, and then diminishing shortly after lights-on. Locomotor activity continued to cycle under constant dark conditions with a mean free-running period of 22.7 h. We also found a second component in the free-running activity (mean 11.5 h) which correlated very tightly with the free-running period. Thus, M. wittfeldae has what can be considered a typical circadian clock resonating with the 24-h day. Notably, however, there were two outliers close to the 19-h period observed in C.Turbinata, suggesting that there may be sufficient variation in clock period among araneid spiders upon which selection could act leading to the short-period clocks in C.Turbinata.

京都大学 / 新制・課程博士 / 博士(薬科学) / 甲第23842号 / 薬科博第157号 / 新制||薬科||17(附属図書館) / 京都大学大学院薬学研究科医薬創成情報科学専攻 / (主査)教授 土居 雅夫, 教授 竹島 浩, 教授 中山 和久 / 学位規則第4条第1項該当 / Doctor of Pharmaceutical Sciences / Kyoto University / DFAM