In this paper, we describe a single system image (SSI) architecture for distributed systems. The SSI architecture is constructed through three components: single process space (SPS), process migration, and dynamic load balancing. These components attempt to share all available resources in the cluster among all executing processes, so that the distributed system operates like a single node with much more computing power. To this end, we first resolve broken pipe problems and bind errors on server socket in process migration. Second, we realize SPS based on block process identifier (PID) allocation. Finally, we design and implement a dynamic load balancing scheme. The dynamic load balancing scheme exploits our novel metric, effective tasks, to effectively distribute jobs to a large distributed system. The experimental results show that these three components present scalability, new functionality, and performance improvement in distributed systems.

The measurement of the 3-dimensional behavior of early reflections in a sound field has been an important issue in auditorium acoustics since the reflection profile has been found to be strongly correlated with the subjective responsiveness of a listener. In order to detect the incidence angle and relative amplitude of reflections, a 4-point microphone system has conventionally been used. A new measurement system is proposed in this paper, which has 5 microphones. Microphones are located on each four apex of a tetrahedron and at the center of gravity. Early reflections, including simultaneously incident reflections,which previous 4-point microphone system could not discriminate as individual wavefronts, were successfully found with the new system. In order to calculate accurate image source positions, it is necessary to determine the exact peak positions from measured impulse responses composed of highly deformed and overlapped impulse trains. For this purpose, a peak-detecting algorithm, which finds dominant peaks in the impulse response by an iteration method, is introduced. In this paper, the theoretical background and features of the 5-microphone system are described. Also, some results of experiments using this system are described.

Modern microprocessors achieve high application performance at the acceptable level of power dissipation. In terms of power to performance trade-off, the instruction window is particularly important. This is because enlarging the window size achieves high performance but naive scaling of the conventional instruction window can severely increase the complexity and power consumption. In this paper, we propose low-power instruction window techniques for contemporary microprocessors. First, the small reorder buffer (SROB) reduces power dissipation by deferred allocation and early release. The deferred allocation delays the SROB allocation of instructions until their all data dependencies are resolved. Then, the instructions are executed in program order and they are released faster from the SROB. This results in higher resource utilization and low power consumption. Second, we replace a conventional issue queue by a direct lookup table (DLT) with an efficient tag translation technique. The translation scheme resolves the instruction dependency, especially for the case of one producer to multiple consumers. The efficiency of the translation scheme stems from the fact that the vast majority of instruction dependency exists within a basic block. Experimental results show that our proposed design reduces the power consumption significantly for SPEC2000 benchmarks.

In Feb 2021, As the competition for commercialization of 5G mobile communication has been increasing, 5G SA Network and Vo5G are expected to be commercialized soon. 5G mobile communication aims to provide 20 Gbps transmission speed which is 20 times faster than 4G mobile communication, connection of at least 1 million devices per 1 km2, and 1 ms transmission delay which is 10 times shorter than 4G. To meet this, various technological developments were required, and various technologies such as Massive MIMO (Multiple-Input and Multiple-Output), mmWave, and small cell network were developed and applied in the area of 5G access network. However, in the core network area, the components constituting the LTE (Long Term Evolution) core network are utilized as they are in the NSA (Non-Standalone) architecture, and only the changes in the SA (Standalone) architecture have occurred. Also, in the network area for providing the voice service, the IMS (IP Multimedia Subsystem) infrastructure is still used in the SA architecture. Here, the issue is that while 5G mobile communication is evolving openly to provide various services, security elements are vulnerable to various cyber-attacks because they maintain the same form as before. Therefore, in this paper, we will look at what the network standard for 5G voice service provision consists of, and what are the vulnerable problems in terms of security. And We Suggest Possible Attack Scenario using Security Issue, We also want to consider whether these problems can actually occur and what is the countermeasure.

This paper proposes a proactive management system for the events that occur across multiple personal user devices, including desktop PCs, laptops, and smart phones. We implemented the Personal Event Management Service using Dynamic Bayesian Networks (PEMS-DBN) system that proactively executes appropriate tasks across multiple devices without explicit user requests by recognizing the user's device reuse intention, based on the observed actions of the user for specific devices. The client module of PEMS-DBN installed on each device monitors the user actions and recognizes user intention by using dynamic Bayesian networks. The server provides data sharing and maintenance for the clients. A series of experiments were performed to evaluate user satisfaction and system accuracy, and also the amounts of resource consumption during intention recognition and proactive execution are measured to ensure the system efficiency. The experimental results showed that the PEMS-DBN system can proactively provide appropriate, personalized services with a high degree of satisfaction to the user in an effective and efficient manner.

In this paper, we study a distributed time-reversal space-time block coded single-carrier (D-TR-STBC-SC) system for amplify-and-forward (AF) half-duplex relaying in frequency-selective Rayleigh fading channels. Under the imperfect channel estimation condition, we analyze the mean-square-error (MSE) performance of the optimal and channel-mismatched frequency domain minimum MSE (FD-MMSE) and least square (LS) equalization. Our analysis results show that, unlike the point-to-point communications, the channel-mismatched FD-MMSE equalization of D-TR-STBC-SC relaying network leads to the ceiling effect that the MSE increases as the signal-to-noise ratio (SNR) of relay-to-destination link increases. Decomposing the MSE, it is found that the primary cause of the ceiling effect is the source-to-destination link in the first time-slot, which makes the covariance matrix of noise vector ill-conditioned. In order to resolve the channel-mismatching problems in the equalization process, we develop optimum relay power control strategies by considering practical channel estimations, i.e., training-based LS and linear minimum MSE (LMMSE) channel estimations. It is shown that the optimum power control resolves the trade-off between MSE performance and relay power consumption, and improves the robustness against the channel-mismatching. Finally, we introduce a performance evaluation to demonstrate the performance of channel equalization combined with the proposed power controls in D-TR-STBC-SC relaying network.

The growth behavior of copper particle on crystalline and amorphous silicon surfaces has been investigated. The study reveals that the growth behavior of copper particle depends on the substrate condition. When samples are intentionally contaminated in ultrapure water, both crystalline and amorphous silicon surfaces show no difference in their contamination levels. However, copper particles were not observed on an amorphous silicon surface except dipping in dilute CuCl2 solution. The copper concentration on an amorphous silicon surface after dipping in a 0.5% HF solution is similar to the level after contaminating in ultrapure water. The copper contamination level on a crystalline silicon surface, except from CuCl2 solution, decreased two orders of magnitude as compared with ultrapure water. The copper impurity level on crystalline silicon surface was reduced by two orders by cleaning in a sulfuric acid-hydrogen peroxide mixture. The sulfuric acid-hydrogen peroxide mixture cleaning was not effective on an amorphous silicon surface. When native oxide pre-existed on an amorphous silicon surface before contamination, however, the sulfuric acid-hydrogen peroxide mixture cleaning was effective for removing copper impurity. Our results suggest that copper contamination on an amorphous silicon surface have the characteristics of bonding directly with silicon and/or existing in the native oxide, in contrast with the situation on crystalline silicon surface. After contamination with 1000 ppm copper in CuF2 solution, the etch rate of an amorphous silicon film in a 0.5% HF solution was approximately one order of magnitude faster than that of crystalline silicon. This is attributed to the difference in crystalline structure between crystalline silicon and amorphous silicon.

This paper proposes a framework for building a customized comparison-shopping system in which the users are allowed to add their own shopping stores dynamically. In this framework, a shopping agent is implemented with a robust inductive learning method that automatically constructs wrappers for semi-structured online stores. During learning, strong biases assumed in many existing systems are weakened so that the real stores with reasonably complex document structures can be handled.

Time variation within an OFDM symbol causes inter-carrier interference (ICI). In this letter, frequency-domain partial response coding (PRC) is investigated to reduce ICI in the Alamouti SFBC-OFDM system. Based on the expression of the ICI power in the SFBC-OFDM system with PRC, the near-optimal weights of PRC are derived. Simulation results show that the PRC scheme can reduce ICI effectively.