Parameter-free geometric document layout analysis

Automatic transformation of paper documents into electronic documents requires geometric document layout analysis at the first stage. However, variations in character font sizes, text line spacing, and document layout structures have made it difficult to design a general-purpose document layout analysis algorithm for many years. The use of some parameters has therefore been unavoidable in previous methods. The authors propose a parameter-free method for segmenting the document images into maximal homogeneous regions and identifying them as texts, images, tables, and ruling lines. A pyramidal quadtree structure is constructed for multiscale analysis and a periodicity measure is suggested to find a periodical attribute of text regions for page segmentation. To obtain robust page segmentation results, a confirmation procedure using texture analysis is applied to only ambiguous regions. Based on the proposed periodicity measure, multiscale analysis, and confirmation procedure, we could develop a robust method for geometric document layout analysis independent of character font sizes, text line spacing, and document layout structures. The proposed method was experimented with the document database from the University of Washington and the MediaTeam Document Database. The results of these tests have shown that the proposed method provides more accurate results than previous ones     

工业循环冷却水处理药剂阻垢性能实验的探讨

通过实验对比,得出实验温度、实验时间及浓缩倍数对水处理药剂阻垢率的影响,筛选出显著影响因素,用于指导阻垢剂的选择及性能的鉴定。     

Efficient blind dereverberation and echo cancellation based on independent component analysis for actual acoustic signals

This letter presents a new algorithm for blind dereverberation and echo cancellation based on independent component analysis (ICA) for actual acoustic signals. We focus on frequency domain ICA (FD-ICA) because its computational cost and speed of learning convergence are sufficiently reasonable for practical applications such as hands-free speech recognition. In applying conventional FD-ICA as a preprocessing of automatic speech recognition in noisy environments, one of the most critical problems is how to cope with reverberations. To extract a clean signal from the reverberant observation, we model the separation process in the short-time Fourier transform domain and apply the multiple input/output inverse-filtering theorem (MINT) to the FD-ICA separation model. A naive implementation of this method is computationally expensive, because its time complexity is the second order of reverberation time. Therefore, the main issue in dereverberation is to reduce the high computational cost of ICA. In this letter, we reduce the computational complexity to the linear order of the reverberation time by using two techniques: (1) a separation model based on the independence of delayed observed signals with MINT and (2) spatial sphering for preprocessing. Experiments show that the computational cost grows in proportion to the linear order of the reverberation time and that our method improves the word correctness of automatic speech recognition by 10 to 20 points in a RT??= 670 ms reverberant environment.     

An enhanced cross-layer fast handover scheme for mobile IPv6 in the IEEE 802.16e networks

The IEEE 802.16e standard enhances the IEEE 802.16 for the mobility support. Mobile stations can move while receiving services, thus ongoing IP sessions may be maintained during a handover in the IEEE 802.16e. To reduce handover latency, the idea of cross-layer handover which incorporates layer 2 handover with IP layer has been devised. Various cross-layer handover schemes supporting fast handover in the IEEE 802.16e networks have been proposed. However, the problem of the conventional cross-layer fast handover schemes is that they are heavily influenced by the new address confirmation latency which is the most time-consuming procedure. In this paper, we propose an enhanced cross-layer fast handover scheme which is not susceptible to the new address confirmation latency. Detailed performance analysis is performed in terms of the signaling costs and the handover latencies to show the effectiveness of the proposed scheme compared with the conventional ones. The results of the performance evaluation confirm the effectiveness of the proposed scheme.     

A new dimmer for alternating-current directly driven light-emitting-diode lamp

A new dimmer using a mental-oxide-semiconductor field-effect transistor (MOSFET) for alternating-current (AC) directly driven light-emitting-diode (LED) lamp was presented. The control method of proposed dimmer is pulse width control (PWM) method. Compared with the conventional phase-controlled dimmer, the proposed PWM dimmer can produce sine wave and did not cause harmonics problem. Furthermore, the proposed control method did not amplify the light flicker due to the independence of input voltage. Therefore, the PWM dimmer can be used as the dimmer of the AC LED lamp instead of the conventional phase-controlled dimmer. The experimental result shows that the proposed PWM dimmer has good performances.     

Improving Application Launch Performance on Solid State Drives

Application launch performance is of great importance to system platform developers and vendors as it greatly affects the degree of users’ satisfaction.The single most effective way to improve application launch performance is to replace a hard disk drive (HDD) with a solid state drive (SSD),which has recently become affordable and popular.A natural question is then whether or not to replace the traditional HDD-aware application launchers with a new SSD-aware optimizer.We address this question by analyzing the inefficiency of the HDD-aware application launchers on SSDs and then proposing a new SSD-aware application prefetching scheme,called the Fast Application STarter (FAST).The key idea of FAST is to overlap the computation (CPU) time with the SSD access (I/O) time during an application launch.FAST is composed of a set of user-level components and system debugging tools provided by Linux OS (operating system).Hence,FAST can be easily deployed in any recent Linux versions without kernel recompilation.We implement FAST on a desktop PC with an SSD running Linux 2.6.32 OS and evaluate it by launching a set of widely-used applications,demonstrating an average of 28% reduction of application launch time as compared to PC without a prefetcher.     

Loss mechanisms and high power piezoelectrics

Heat generation is one of the significant problems in piezoelectrics for high power density applications. In this paper, we review the loss mechanisms in piezoelectrics first, followed by the heat generation processes for various drive conditions. Heat generation at off-resonance is caused mainly by dielectric loss tan δ′ (i.e., P-E hysteresis loss), not by mechanical loss, while the heat generation at resonance is mainly attributed to mechanical loss tan φ′. Then, practical high power materials developed at Penn State is introduced, which exhibit the vibration velocity more than 1 m/s, leading to the power density capability 10 times of the commercially available “hard” PZTs. We propose a internal bias field model to explain the low loss and high power origin of these materials. Finally, using a low temperature sinterable “hard” PZT, we demonstrated a high power multilayer piezoelectric transformers.     

A new low-cost RF built-in self-test measurement for system-on-chip transceivers

This paper presents a new RF built-in self-test (BIST) measurement and a new automatic-performance-compensation network for a system-on-chip (SoC) transceiver. We built a 5-GHz low noise amplifier (LNA) with an on-chip BIST circuit using 0.18-/spl mu/m SiGe technology. The BIST-measurement circuit contains a test amplifier and RF peak detectors. The complete measurement setup contains an LNA with a BIST circuit, an external RF source, RF relays, 50-/spl Omega/ load impedance, and a dc voltmeter. The proposed BIST circuit measures input impedance, gain, noise figure, input return loss, and output signal-to-noise ratio of the LNA. The test technique utilizes the output dc-voltage measurements, and these measured values are translated to the LNA specifications such as the gain through the developed equations. The performance of the LNA was improved by using the new automatic compensation network (ACN) that adjusts the performance of the LNA with the processor in the SoC transceiver.     

Synchronous-frame current control of multiphase synchronous motor under asymmetric fault condition due to open phases

In this paper, a synchronous-frame current controller of a multiphase synchronous motor with open phases is proposed. The proposed method cannot only possess the superiority of a linear controller over the conventional hysteresis-type current controller but it also enables the current to be regulated without a steady-state error. The key idea is that all the harmonics of the current and voltage, which can still contribute to the torque positively, can be equivalently represented as dc components even under asymmetric fault conditions. Throughout this paper, a five-phase synchronous motor with one open phase is used as a practical example, and the basic concepts can be easily extended into an n-phase ac motor with multiple open phases, which has the arbitrary number or configuration of the remaining healthy phases. Experimental results prove the validity of the proposed modeling and control algorithm.     

新型水库调度自动化系统

主要对具有可组态的、多阶层的新型水库调度自动化系统进行了分析， 并简要介绍国家电力调度中心水库调度自动化系统的部分应用情况。