As one of the most popular intelligent optimization algorithms, Simulated Annealing (SA) faces two key problems, the generation of perturbation solutions and the control strategy of the outer loop (cooling schedule). In this paper, we introduce the Gaussian Cloud model to solve both problems and propose a novel cloud annealing algorithm. Its basic idea is to use the Gaussian Cloud model with decreasing numerical character He (Hyper-entropy) to generate new solutions in the inner loop, while He essentially indicates a heuristic control strategy to combine global random search of the outer loop and local tuning search of the inner loop. Experimental results in function optimization problems (i.e. single-peak, multi-peak and high dimensional functions) show that, compared with the simple SA algorithm, the proposed cloud annealing algorithm will lead to significant improvement on convergence and the average value of obtained solutions is usually closer to the optimal solution.

High energy cost is a big challenge faced by the current data centers, wherein computing energy and cooling energy are main contributors to such cost. Consolidating workload onto fewer servers decreases the computing energy. However, it may result in thermal hotspots which typically consume greater cooling energy. Thus the tradeoff between computing energy decreasing and cooling energy decreasing is necessary for energy saving. In this paper, we propose a minimized-total-energy virtual machine (VM for short) migration model called C2vmMap based on efficient tradeoff between computing and cooling energies, with respect to two relationships: one for between the resource utilization and computing power and the other for among the resource utilization, the inlet and outlet temperatures of servers, and the cooling power. Regarding online resolution of the above model for better scalability, we propose a VM migration algorithm called C2vmMap_heur to decrease the total energy of a data center at run-time. We evaluate C2vmMap_heur under various workload scenarios. The real server experimental results show that C2vmMap_heur reduces up to 40.43% energy compared with the non-migration load balance algorithm. This algorithm saves up to 3x energy compared with the existing VM migration algorithm.

In order to improve the detection performance in passive millimeter-wave (PMMW) imaging, a new method forwarding a null in the direction of human body and objects is proposed. The forward-nulling PMMW imaging using a dielectric tube occupied by cooling water placed near the focus line of a parabolic cylinder are performed. It is shown experimentally that the contrast between human body and conducting objects such as a conducting plate and a conducting sphere is improved by the presence of the cooling dielectric tube and parabolic cylinder.

Superconductivity and superconducting electronics have quite a prominent place in the European research environment and can look back onto a successful history. In recent years the European Framework programs helped to enhance the interaction between the different national research institutions, universities and industry. For applications of superconductivity this was accomplished by the European Network of Excellence SCENET and its sister organization ESAS. In this context a virtual European foundry network was established (Fluxonics), which forms a platform for the superconducting electronics activities in Europe and realizes support for the design and the fabrication of superconducting circuits for research laboratories and industry. Lately quite some development on the digital side and the cooling of superconducting electronics devices has taken place in Europe; most of it within the Fluxonics network. Some of these advances will be reported in this overview article.

This development proposes a highly efficient air-conditioning airflow system for a computer-machine room having high-heat-generating equipment using forced-air cooling. The proposed system recirculates room air in the area surrounding equipment back to the cooling supply air supplied from a double floor. The recirculated air is therefore used as cooling air for computers. This system enables the blowing temperature difference of air-conditioner units to be increased, blower capacity to be decreased, and overall efficiency of air-conditioner units to be increased. Here, we have proposed an air-conditioning airflow system that decreases the amount of cooling supply air while ensuring adequate air ventilation for equipment using forced-air cooling, and a design method for achieving this system.

The small planar packaging (SPP) system described here can be combined with card-on-board (COB) packaging in high-speed asynchronous transfer mode (ATM) switching systems with throughput of over 40-Gb/s. The SPP system provides high I/O pin count density, high packaging density and high cooling capability. Prototype SPP system with air flow control structure for switching MCMs is constructed. Each MCM contained a 35 array of low thermal resistance butt-lead pin-grid-array on a glass ceramic substrate measuring 100170 mm with a plate fin heat-sink. This allows a power dissipation of more than 125 W per MCM, and 300 W per printed circuit board (PCB). Obtained board level heat flux density of the SPP system is 0. 37 W/cm2, which is six times that of conventional COB packaging. The SPP system combined with the COB packaging provides a small system foot-print and compact hardware for high-speed, large capacity ATM switching systems. This high-performance air cooling technology will be especially useful for future broadband ISDN high-speed switching systems.

A simulation model for natural convection was developed for determining the surface temperature distribution in base plates with rectangular vertical fins in communication equipment. An estimated velocity derived from the buoyancy and pressure drop equations in a duct was used for laminar forced convection cooling simulations in parallel plates. Temperature distributions in finned plates were calculated by numerical integration of the heat conduction equation. An experimental study was also performed, to check these simulation results, by changing the height of fins, the pitch of fins, and the heat generation conditions. Experimental results and analytical results were found to agree well. Also, this simulation method was extended to analyze natural convection cooling in vertical base plates with inclined parallel fins. We placed alternately on the plates the sections without fins and the sections with fins on the plates. Using the inclined fins, air flow rate between fins was large and fresh air flew into the fins from the side of the plates. The natural convective heat-transfer rate for inclined fins was found to be 14% higher than that for vertical fins.

Widely tunable coherent terahertz (THz)-wave generation was successfully demonstrated based on the laser light scattering from the lowest A1-symmetry polariton mode by using a Q-switched Nd:YAG laser pumping. This method exhibits multiple advantages like wide tunability (frequency: 0. 9-2. 2 THz), coherency and compactness of its system. In this paper, the general performances of this THz-wave generator, as well as the recent development of the system and its application are reported. Measurements of tunability, coherency, power, polarization, radiation angle, and divergence are shown. The cryogenic cooling of the crystal was performed in addition, and a more than one hundred times higher THz-wave output was observed. A spectroscopic application of our wave source is demonstrated by measuring the water vapor absorption.

Six chips of the GaAs standard cell LSIs have been developed for a synchronous digital hierarchy (SDH) interface unit in 10 Gbit/s optical communication systems. Two of them are the frame termination LSIs for SDH, and four are the byte multiplexing and demultiplexing LSIs. The LSI configuration with a careful thermal design were needed to realize a natural air-cooling operation. As a result, the unit was composed of eight chips with six kind of LSIs and these LSIs consist of 1 K to 3 K gates. The LSIs were designed with the standard cell libraries based on 0.5µm gate DCFL (Direct Coupled FET Logic) operating at a low power supply voltage of 1.5V. The propagation delay time of standard DCFL inverter was 25 ps with a power consumption of 0.45mW in the experimental results. The LSI design methodology using these libraries were discussed to achieve the data processing of 1.25 Gbit/s signals under a natural air-cooling condition. The maximum operating speeds of them were at least 1.4 GHz and the power consumptions were as low as under 1.8 W, which resulted in fully high speed operations under a natural air-cooling condition at an ambient temperature of 100.

This paper describes an innovative heat-pipe cooling technology for asynchronous transfer mode (ATM) switching multichip modules (MCMs) operating with a throughput of 40 Gb/s. Although high-speed ATM link-wires are connected at the top surface of the MCMs, there is no room to cool the MCM by forced air convection, because power and the system clock signal are supplied by connectors on the rear and periphery of the MCM. We therefore chose to attach a cold-plate to the back of each MCM. The condenser part of the heat pipe, which is mounted behind the power supply printed circuit board, is cooled by low-velocity forced air. Total power dissipation is about 30 watts per MCM. With a 2 m/s foreced airflow, the sub-switching-element module (four MCMs) operates at a throughput of 80 Gb/s with a maximum junction temperature of less than 85. Measured thermal resistance between the switch LSI junction and air is about 6/W. This heat-pipe cooling system has a small system footprint, compact hardware, and good cooling capacity.

Heat recovery methods and the amount of heat that can be recovered from fuel cell exhaust gas is described. The cooling performance of an absorption refrigerator that uses fuel cell waste heat is also described. Two heat recovery methods from the exhaust gas are considered: one uses heat recovery from mixed exhaust gas from the cathode side of the cells and the reformer (mixed type); the other uses separate heat recovery from these sites (separate type). Simulation shows that the amount of heat recovered between 60 and 75 with the separate type of heat recovery is greater than with the mixed type of heat recovery. The cooling capacity of the refrigerator using the separate type heat recovery and recovering heat between 65 and 85 is about 2.5 times that of one using a generator (heat source) with a constant 85 temperature.