Browsing by Author "Chung, Yeh-Ching"

Now showing 1 - 7 of 7

A Method-Based Ahead-of-Time Compiler for Android Applications
(2011-01-01)
Wang, Chih-Sheng
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Perez, Guillermo A.
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Chung, Yeh-Ching
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Hsu, Wei-Chung
;
Shih, Wei-Kuan
The execution environment of Android system is based on a virtual machine called Dalvik virtual machine (DVM) in which the execution of an application program is in interpret-mode. To reduce the interpretation overhead of DVM, Google has included a trace-based just-in-time compiler (JITC) in the latest version of Android. Due to limited resources and the requirement for reasonable response time, the JITC is unable to apply deep optimizations to generate high quality code. In this paper, we propose a method-based ahead-of-time compiler (AOTC), called Icing, to speed up the execution of Android applications without the modification of any components of Android framework. The main idea of Icing is to convert the hot methods of an application program from DEX code to C code and uses the GCC compiler to translate the C code to the corresponding native code. With the Java Native Interface (JNI) library, the translated native code can be called by DVM. Both AOTC and JITC have their strength and weakness. In order to combine the strength and avoid the weakness of AOTC and JITC, in Icing, we have proposed a cost model to determine whether a method should be handled by AOTC or JITC during profiling. To evaluate the performance of Icing, four benchmarks used by Google JITC are used as test cases. The performance results show that, with Icing, the execution time of an application is two to three times faster than that without JITC, and 25% to 110% faster than that with JITC.
An IoT-Based Cloud-Fog Computing Platform for Creative Service Process
(2017-01-01)
Hsu, Tse-Chuan
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Hsu, Terng-Yin
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Yang, Hongji
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Chung, Yeh-Ching
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資訊工程學系
The creative service process is an innovative process that uses newly developed technologies to improve the service models currently used. In this paper, we proposed an IoT-based Cloud-Fog computing platform for the creative service process. The proposed Cloud-Fog computing platform is a distributed computing platform where compute, storage, and network systems of Cloud and Fog are working independently or collaboratively depending on the services performed by the platform. If a service requires resources either from Cloud or Fog, then only the designated Cloud or Fog will be involved. Otherwise, both Cloud and Fog will be collaborated to each other for the service. During the collaboration, the required data may be back and forth in between Cloud and Fog. To demonstrate the usage of the proposed platform for the creative service process, two service examples, smart classroom and city surveillance, are discussed
Building a KVM-based Hypervisor for a Heterogeneous System Architecture Compliant System
(2016-07)
Huang, Yu-Ju
;
Wu, Hsuan-Heng
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Chung, Yeh-Ching
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Hsu, Wei-Chung
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資訊工程學系
Heterogeneous System Architecture (HSA) is an architecture developed by the HSA foundation aiming at reducing programmability barriers as well as improving communication efficiency for heterogeneous computing. For example, HSA allows heterogeneous computing devices to share the same virtual address space. This feature allows programmers to bypass explicit data copying between devices, as was required in the past. HSA features such as job dispatching through user level queues and memory based signaling help to reduce communication latency between the host and other computing devices. While the new features in HSA enable more efficient heterogeneous computing, they also introduce new challenges to system virtualization, especially in memory virtualization and I/O virtualization. This work investigates the issues involved in HSA virtualization and implements a KVM-based hypervisor that supports the main features of HSA inside guest operating systems. Furthermore, this work shows that with the newly introduced hypervisor for HSA, system resources in HSA-compliant AMD Kaveri can be effectively shared between multiple guest operating systems.
Building a KVM-based Hypervisor for a Heterogeneous System Architecture Compliant System
(2016-07)
Huang, Yu-Ju
;
Wu, Hsuan-Heng
;
Chung, Yeh-Ching
;
Hsu, Wei-Chung
;
資訊工程學系
Heterogeneous System Architecture (HSA) is an architecture developed by the HSA foundation aiming at reducing programmability barriers as well as improving communication efficiency for heterogeneous computing. For example, HSA allows heterogeneous computing devices to share the same virtual address space. This feature allows programmers to bypass explicit data copying between devices, as was required in the past. HSA features such as job dispatching through user level queues and memory based signaling help to reduce communication latency between the host and other computing devices. While the new features in HSA enable more efficient heterogeneous computing, they also introduce new challenges to system virtualization, especially in memory virtualization and I/O virtualization. This work investigates the issues involved in HSA virtualization and implements a KVM-based hypervisor that supports the main features of HSA inside guest operating systems. Furthermore, this work shows that with the newly introduced hypervisor for HSA, system resources in HSA-compliant AMD Kaveri can be effectively shared between multiple guest operating systems.
Coalitional Game Formulation for Multi-Channel Cooperative Cognitive Radio Networks
(2011)
Chan, Yu-Wei
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Chang, Ronald Y.
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Chien, Feng-Tsun
;
Chang, Min-Kuan
;
Chung, Yeh-Ching
In this paper, we study a coalitional game approach to resource allocation in a multi-channel cooperative cognitive radio network with multiple primary users (PUs) and secondary users (SUs). We propose to form the grand coalition by grouping all PUs and SUs in a set, where each PU can lease its spectrum to all SUs in a time-division manner while the SUs in return help the data transmission of PUs by relaying. The grand coalition is shown to be stable in the considered scenario by justifying that the solution concept of the coalitional game (the core) is nonempty. Also, optimal relay strategies of SUs, to relay or to transmit its own data, are obtained so that the sum rate of all PUs and SUs is maximized. Finally, we demonstrate in simulation the benefits of the grand coalition comparing to the case of direct transmission only and other forms of coalitions as well.
Genetic copy number variants in myocardial infarction patients with hyperlipidemia
(2011-11-30)
Shia, Wei-Chung
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Ku, Tien-Hsiung
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Tsao, Yu-Ming
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Hsia, Chien-Hsun
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Chang, Yung-Ming
Background: Cardiovascular disease is the chief cause of death in Taiwan and many countries, of which myocardial infarction (MI) is the most serious condition. Hyperlipidemia appears to be a significant cause of myocardial infarction, because it causes atherosclerosis directly. In recent years, copy number variation (CNV) has been analyzed in genomewide association studies of complex diseases. In this study, CNV was analyzed in blood samples and SNP arrays from 31 myocardial infarction patients with hyperlipidemia. Results: We identified seven CNV regions that were associated significantly with hyperlipidemia and myocardial infarction in our patients through multistage analysis (P<0.001), at 1p21.3, 1q31.2 (CDC73), 1q42.2 (DISC1), 3p21.31 (CDCP1), 10q11.21 (RET) 12p12.3 (PIK3C2G) and 16q23.3 (CDH13), respectively. In particular, the CNV region at 10q11.21 was examined by quantitative real-time PCR, the results of which were consistent with microarray findings. Conclusions: Our preliminary results constitute an alternative method of evaluating the relationship between CNV regions and cardiovascular disease. These susceptibility CNV regions may be used as biomarkers for early-stage diagnosis of hyperlipidemia and myocardial infarction, rendering them valuable for further research and discussion.
Spectrum sharing in multi-channel cooperative cognitive radio networks: a coalitional game approach
(2013-10-01)
Chan, Yu-Wei
;
Chien, Feng-Tsun
;
Chang, Ronald Y.
;
Chang, Min-Kuan
;
Chung, Yeh-Ching
In this paper, we study a coalitional game approach to resource allocation in a multi-channel cooperative cognitive radio network with multiple primary users (PUs) and secondary users (SUs). We propose to form the grand coalition by grouping all PUs and SUs in a set, where each PU can lease its spectrum to all SUs in a time-division manner while the SUs in return assist PUs' data transmission as relays. We use the solution concept of the core to analyze the stability of the grand coalition, and the solution concept of the Shapley value to fairly divide the payoffs among the users. Due to the convexity of the proposed game, the Shapley value is shown to be in the core. We derive the optimal strategy for the SU, i.e., transmitting its own data or serving as a relay, that maximizes the sum rate of all PUs and SUs. The payoff allocations according to the core and the Shapley value are illustrated by an example, which demonstrates the benefits of forming the grand coalition as compared with non-coalition and other coalition schemes.