The well-known software company, Google,announced a new handset platform named Android on 5 November 2007, which makes a dramatic impact on the mobile platform market. Later, Open Handset Alliance (OHA) continues to develop Android platform, and to date, the mobile development platform has become the most popular one. However, how to save the power and extend the waiting time are important issues to both academic and industrial communities. Currently, there are few intelligent programs developed to save the power at the Android Market, and these programs are usually short of some functions. Moreover,the Android SDK provides no setting functions to adjust the CPU state. So this paper studies and develops several kernel programs. The targets of our programs are to not only monitor common-use programs on the background, but also dynamically adjust the CPU frequency on the platform according to application programs on executing.Several interfaces are provided such that users can manually adjust the mode and frequency of CPU, view the statistic information, and so on. Furthermore, we also collect many settings of saving the power into our program, which makes users straightforward and easy to manipulate.

The emission of polycyclic aromatic hydrocarbons (PAHs) from the diesel engine on a dynamometer by mixing ratio of the fuel (H2/O2 /diesel) was investigated. The engine was operated at a one load steady-state condition of 1,600 rpm with torque and power outputs of 145 Nm and 24.5 kW. In this condition, the measurement of the mixing ratio of the fuel (H2/O2 /diesel) was first recorded without any induction of H2/O2 mixture (Base) into the engine. Then, seven flow rate levels of H2/O2 mixture were used by 10 L/min, 20 L/min, 30 L/min, 40 L/min, 50 L/min, 60 L/min, and 70 L/min, respectively. The concentrations of total PAHs were 106.58, 101.89, 95.30, 90.70, 85.98, 82.35, 72.38, and 67.30 £gg/m3, respectively for Base (0 L/min), 10 L/min, 20 L/min, 30 L/min, 40 L/min, 50 L/min, 60 L/min, and 70 L/min of H2/O2 mixture. The emission factor of total PAHs were 6.00, 5.73, 5.36, 4.99, 4.84, 4.50, 4.07, and 3.78 mg/bhp-hr, respectively for Base (0 L/min), 10 L/min, 20 L/min, 30 L/min, 40 L/min, 50 L/min, 60 L/min, and 70 L/min of H2/O2 mixture. The removal rate of total PAHs were 4.4%, 10.6%, 14.9%, 19.3%, 22.7%, 32.1%, and 36.9%, respectively for 10 L/min, 20 L/min, 30 L/min, 40 L/min, 50 L/min, 60 L/min, and 70 L/min of H2/O2 mixture. This result showed using H2/O2 mixture significantly reduced emissions of PAHs. As the regulated harmful matters, using H2/O2 mixture, CO¡BCO2¡BTHC and PM decreased, whereas the NOx emission increased. The energy saving of the fuels (H2/O2 /diesel), the total oil equivalents combined by fuel consumption of diesel engine and electricity consumption of H2/O2 generator, were 2.42, 2.49, 2.50, 2.48, 2.51, 2.35, 2.18, and 2.17 for Base (0 L/min), 10 L/min, 20 L/min, 30 L/min, 40 L/min, 50 L/min, 60 L/min, and 70 L/min of H2/O2 mixture. The result showed that reduced saving energy of the fuel (H2/O2 /diesel) by 3.2% for 50 L/min, 9.8% for 60 L/min, and 10.4% for 70 L/min, respectively.

Hydrogen is generally acknowledged to have a high heat value and emit few pollutants. It has been identified as the fuel with the most potential for the twenty-first century. This study investigates energy saving and pollutant reduction for polycyclic aromatic hydrocarbons (PAHs), hydrocarbons (HCs), carbon monoxide (CO), carbon dioxide (CO2), particulate matter (PM), and nitrogen oxides and a hydrogen (H2) and oxygen (O2) mixture (H2/O2) mixed in a diesel engine combustion chamber. Experimental parameters included a speed of 1600 rpm and a torque of 145 Nm in the steady-state condition. These operating conditions represent a speed of 40km/hr, roughly vehicle speed in an urban area. In this study, premium diesel fuel (PDF) was mixed with H2/O2 at different injection rates. When mixed with PDF, the H2/O2 injection rate was set to 60L/min, while different biodiesel injection rates were used in the diesel engine combustion chamber. In addition, this study used mathematical simulation to model the combustion temperature, combustion efficiency, and combustion gas distribution in the combustion chamber. The results of PDF mixed under different H2/O2 injection rates showed that the brake thermal efficiency (BTE) did not significantly change when the H2/O2 injection rate rose from 0 L/min to 40L/min, but markedly increased when the H2/O2 injection rate increased from 50 L/min to 70L/min. The best BTE of the diesel engine was 35.4% at an H2/O2 injection rate of 60 L/min, roughly 12.6% higher than PDF. The brake specific fuel consumption (BSFC) was 16.287 g/bhp-hr at an H2/O2 injection rate of 60 L/min, 11.72% lower than PDF. The results of the BTE and BSFC showed that an H2/O2 injection rate of 60 L/min enabled the best performance of the diesel engine. Emissions of CO, CO2, THC, PM, and PAHs fell as the H2/O2 injection rate increased, while the NOx emission increased as the H2/O2 injection rate increased. This was because the addition of H2/O2 improved the combustion efficiency of the fuel. The total oil equivalent saving was about 22.13% compared to neat diesel at an H2/O2 injection rate of 70 L/min. The BTE decreased from 37.0% to 35.5% while the BSFC increased to 149.75 g/bhp-hr when the PDF was mixed with biodiesel and the injection rate of H2/O2 was set at 60 L/min. These results showed that the performance of the diesel engine declined slightly. The BTE of the 30% biodiesel + PDF decreased roughly 1.5% compared to pure PDF. The emissions of CO, THC, and PAHs decreased as the percentage of biodiesel mixed with PDF increased, but CO2, NOx, and PM increased as the proportion of biodiesel rose. In the mathematical simulation, H2/O2 was mixed with combustion air at injection rates of 0, 30, 60, and 70 L/min, using C12H26 as the main fuel. The simulation investigated the combustion flame temperature, fuel combustion efficiency, and combustion gas distribution in the diesel engine combustion chamber. The results showed that the combustion temperature and combustion efficiency improved as the H2/O2 injection rate increased.

The reduction green house gases (GHG) and migitation of climate change have become great challenges to mankind. Taiwan¡¦s households, which account for about 13% of the GHG emissions in Taiwan, are certainly a target for GHS and energy reduction. Based on the theory of planned behavior and Stern and Gardner's (1981) typology of energy saving behavior, this study proposed a model of curtailment behavior toward climate change (CCC model) and a model of efficiency action toward climate change (ECC model). Results of confirmatory factor analysis showed that both models were useful. The CCC model could predict people's intent to take curtailment actions and actual behavior, whereas the ECC model could predict people's intent to take efficiency actions. However, the functions of independent variables were different by gender in both models. Subjective norm influnce the dependent variable significantly only in ECC model. This study suggests some energy saving methods, according to the literatures and the findings.

Energy is a critical resource in the design of wireless networks since wireless devices are usually powered by batteries. Battery capacity is finite and the progress of battery technology is very slow, with capacity expected to make little improvement in the near future. Under these conditions, many techniques for conserving power have been proposed to increase battery life. In this dissertation we consider two approaches to conserving the energy consumed by a wireless network interface. One technique is to use power saving mode, which allows a node to power off its wireless network interface (or enter a doze state) to reduce energy consumption. The other is to use a technique that suitably varies transmission power to reduce energy consumption. These two techniques are closely related to theMAC (Medium Access Control) layer. With respect to power saving mode, we study IEEE 802.11 PSM (Power Saving Mechanism) and propose a scheme that improves its energy efficiency. We also investigate the interaction between power saving mode and TCP (Transport Control Protocol). As a second approach to conserving energy, we investigate a simple power control protocol, called BASIC, which uses the maximum transmission power for RTS-CTS and the minimum necessary power for DATA-ACK. We identify the deficiency of BASIC, which increases collisions and degrades network throughput, and propose a power control protocol that addresses these problems and achieves energy savings. Since energy conservation is not an issue limited to one layer of the protocol stack, we study a cross layer design that combines power control at the MAC layer and power aware routing at the network layer. One poweraware routing metric is minimizing the aggregate transmission power on a path from source to destination. This metric has been used along with BASIC-like power control under the assumption that it can save energy, which we show to be false. Also, we show that the power aware routing metric leads to a lower throughput. We show that using the shortest number of hops in conjunction with BASIC-like power control conserves more energy than power aware routing with BASIC-like power control.

In this thesis, we focus on mobile networks consist of a single base station as the source transceiver, and multiple mobile stations as the receiving party. Applying energy management on multicasting between the base station and mobile stations, network users can conserve the energy consumed while wating for subscribing data contents to come. We referenced the SMBC-D (Scheduling over Multiple Broadcast Channels--the dynamic model) algorithm proposed by R. Cohen et al., grouping users with high request similarity, partitioning channels with a time-division duplexing scheme, and putting mobile stations into sleep mode during channels that include no subscribing data contents. Since SMBC-D statically schedules fixed size channels, groups request fewer data items will idle their channels after finishing their transmision, while groups request more data items take longer time to finish their transmission. For such problem, we propose a heuristic algorithm that makes use of these idle channels by combining adequate consecutive idle channels, to improve channel utility, and lower the overall energy consumed. We also process relevant computer simulations, verifying that our method has better performance.

In this thesis, we proposed a simple yet novel multicast scheduling scheme for IEEE 802.16e wireless metropolitan area networks. Specifically, we want to solve the problem that how the base station schedules data messages in a multicast superframe such that mobile stations can receive their required multicast data and the total awake time of mobile stations is minimal. We first prove that this problem is NP-complete, and then propose a greedy k-approximation algorithm, named G-EEMS, whose running time is , where n is the total number of multicast data messages and k is the size of MBS (multicast and broadcast service) zone in a frame. Simulation results show that, in terms of energy throughput, G-EEMS significantly outperforms the existing scheme, called SMBC-D.

Thesis supervisor: B Ravikumar. Includes bibliographic references (p. 132-135).

Thesis (Ph. D.)--University of California, San Diego, 2004. / Vita. Includes bibliographical references.

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