Browsing by Author "Su, CY"

Now showing 1 - 17 of 17

A discrete wavelet transform codec design
(2004-12-01)
Hu, YQ
;
Wu, BF
;
Su, CY
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This manuscript presents a VLSI architecture and its design rule, called embedded instruction code (EIC), to realize discrete wavelet transform (DWT) codec in a single chip. Since the essential computation of DWT is convolution, we build a set of multiplication instruction, MUL, and the addition instruction, ADD, to complete the work. We segment the computation paths of DWT according to the multiplication and addition, and apply the instruction codes to execute the operators. Besides, we offer a parallel arithmetic logic unit (PALU) organization that is composed of two multipliers and four adders (2M4A) in our design. Thus, the instruction codes programmed by EIC control the PALU to compute efficiently. Additionally, we establish a few necessary registers in PALU, and the number of registers depends on the wavelet filters' length and the decomposition level. Yet, the numbers of multipliers and adders do not increase as we execute the DWT or the inverse DWT (IDWT) in multilevel decomposition. Furthermore, we deduce the similarity between DWT and IDWT, so the functions can be integrated in the same architecture. Besides, we schedule the instructions; thus, the execution of the multilevel processes can be achieved without superfluous PALU in a single chip. Moreover, we solve the boundary problem of DWT by using the symmetric extension. Therefore, the perfect reconstruction (PR) condition for DWT requirement can be accomplished. Through EIC, we can systematically generate a flexible instruction codes while we adopt different filters. Our chip supports up to six levels of decomposition, and versatile image specifications, e.g., VGA, MPEG-1, MPEG-2, and 1024 x 1024 image sizes. The processing speed is 7.78 Mpixel/s when the operation frequency, for normal case, is 100 MHz.
A fast convolution algorithm for biorthogonal wavelet image compression
(1999-03-01)
Wu, BF
;
Su, CY
;
電控工程研究所
;
Institute of Electrical and Control Engineering
Symmetric filters and symmetric extension of image edges have been widely used in wavelet image compression. Since the filters are symmetric, it is possible to take advantage of the symmetric property to reduce the computational complexity for the filtering. In this paper, we present a fast convolution algorithm for the discrete wavelet transform (DWT) and the inverse DWT (IDWT) such that the transform time can be greatly reduced. Compared with regular convolution, the new algorithm can decrease the multiplication operations by nearly one half. Converted into real programming, it sped up the DWT and IDWT in our experiments by at least 12% and 55%, respectively. Incorporated with enhancing zerotree coding, the proposed algorithm results in a rapid and efficient coder. Experimental results showed that the coder is competitive with other high performance coders. The pro posed convolution algorithm is also suitable for many types of wavelet-based coding, including wavelet video coding.
A low memory zerotree coding for arbitrarily shaped objects
(2003-03-01)
Su, CY
;
Wu, BF
;
電控工程研究所
;
Institute of Electrical and Control Engineering
The Set Partitioning In Hierarchical Trees (SPIHT) algorithm is a computationally simple and efficient zerotree coding technique for image compression. However, high working memory requirement is its main drawback for hardware realization. In this study, we present a low memory zerotree coder (LMZC), which requires much less working memory than WHIT. The LMZC coding algorithm abandons the use of lists, defines a different tree structure, and merges the sorting pass and the refinement pass together. The main techniques of LMZC are the recursive programming and a top-bit scheme (TBS). In TBS, the top bits of transformed coefficients are used to store the coding status of coefficients instead of the lists used in SPIRT. In order to achieve high coding efficiency, shape-adaptive discrete wavelet transforms are used to transformation arbitrarily shaped objects. A compact emplacement of the transformed coefficients is also proposed to further reduce working memory. The LMZC carefully treats "don't care" nodes in the wavelet tree and does not use bits to code such nodes. Comparison of LMZC with SPHIT shows that for coding a 768 x 512 color image, LMZC saves at least 5.3 MBytes(1) of memory but only increases a little execution time and reduces minor peak signal-to noise ratio (PSNR) values, thereby making it highly promising for some memory limited applications.
A macro model of silicon spiral inductor
(2002-05-01)
Su, CY
;
Chen, LP
;
Chang, SJ
;
Tseng, BM
;
Lin, DC
A new automatic parameter extraction method for modeling Of silicon Spiral inductors is presented. The Concepts on self-resonance frequency (f(sr)) and quality factor of a spiral inductor are utilized to develop the concise extraction procedures. In the mean time, the presented extraction procedures are programmed as a macro to execute all the extractions automatically and shorten the extraction time effectively. Without any additional optimization or curve fitting, almost all the patterns of S-parameters between the measured and the simulation of extracted data implemented with the extraction macro are less than 5%. The programmed extraction macro makes it fast and accurate to extract and characterize the behaviours or silicon-based spiral inductors with different structures and substrate resistivities. It provides a concrete foundation commercial silicon radiofrequency (RF) Circuit design to realizing on-chip silicon RF integrated circuits. Furthermore, the directly extracted equivalent model parameters, without an optimization, also provide a rule to fairly, effectively and phsically judge the performance of a spiral inductor. (C) 2002 Elsevier Science Ltd. All rights reserved.
A synthetic approach to tacamonine. Access to 3-epitacamonine and 14-epitacamonine
(2001-01-14)
Ho, TL
;
Su, CY
;
應用化學系
;
Department of Applied Chemistry
3-Epitacamonine and 14-epitacamonine have been synthesized starting from the dinitrile 3. The synthetic route was designed on the basis of symmetric considerations which emphasized the establishment of the relative configuration in two of the three stereocenters. (C) 2001 Elsevier Science Ltd. All rights reserved.
Activated diffusion brazed repair for IN738 hot section components of gas turbines
(2001-09-24)
Su, CY
;
Lih, WC
;
Chou, CP
;
Tsai, HC
;
機械工程學系
The wide-clearance activated diffusion brazing (ADB) techniques with various brazing alloys, namely DF4B and Nicrobraz 150 were applied to restore worn areas of IN738 components. In this study, the microstructure of an ADB joint and the results of thermal cyclic tests as well as tensile tests within the temperature range of from 25 to 980 degreesC were investigated and discussed. The results of the tensile tests showed that ADB specimens brazed by 40 wt.% DF4B at 1190 degreesC exhibited 85% tensile strength of the IN738 base materials at room temperature and retained the same strength as that of the base material at 980 degreesC. However, the ductility of the ADB specimens with both brazing alloys was reduced. The results of cyclic-oxidation tests showed that ADB specimens with Nicrobraz 150 as the brazing alloy decayed after 150 cycles. However, the ADB specimens with DF4B had no obvious weight change until 205 cycles. (C) 2001 Elsevier Science B.V. All rights reserved.
An automatic macro program for radio frequency MOSFET characteristics analysis
(2001-10-01)
Su, CY
;
Chang, SJ
;
Chen, LP
;
Ho, YP
;
Huang, GW
The parameter extraction language (PEL) in Agilent IC-CAP software is used to develop an automatic macro program for the analysis of the characteristics of RF MOSFETs. By using this powerful macro program, the time spent on the measurement of the MOSFET characteristics and the related analysis is effectively reduced. This macro program permits a fast and accurate method to obtain the DC and RF characteristics of MOSFETs with different device geometries and operating conditions. It is also suitable for high volume measurements and analyses of MOSFET, and provides a solid jou 71 dation for RF circuit design.
Approaches to tacamonine.
(2001-04-01)
Ho, TL
;
Su, CY
;
Gorobets, E
;
應用化學系
;
Department of Applied Chemistry
Arbitrarily shaped image coding by using translation invariant wavelet transforms
(1999-12-01)
Wu, BF
;
Su, CY
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This study presents two sets of translation invariant wavelet transforms for coding an arbitrarily shaped image. Each set can be viewed as a shape-adaptive discrete wavelet transform (SA-DWT) with the property of translation invariance. The proposed transform schemes have the following merits: (1) they are translation invariant, (2) no sharp transition appears at the edges of the image, (3) the number of pixels is maintained constant after transformation, (4) the correlation of pixels is fully exploited, and (5) the property of self-similarity across scales is preserved. (C) 1999 Elsevier Science B.V. All rights reserved.
Development of IPv6-IPv4 translation mechanisms for SIP-based VoIP applications
(2005)
Chen, WE
;
Su, CY
;
Weng, JH
;
資訊工程學系
;
Department of Computer Science
This paper presents the development and deployment of two IPv6-IPv4 translation mechanisms (i.e., Socket-layer Translator and SIPv6 Translator) for SIP VoEP applications in Taiwan. The Socket-layer Translator embeds in the TCP(UDP)/IPv4 TSP and translates the IPv4 Winsock function calls to IPv6. The SIPv6 Translator is a translation gateway between IPv6 and IPv4 networks and assists the IPv6 SIP User Agents to communicate with the IPv4 SIP User Agents. These two translation mechanisms can accelerate the IPv6 transition. This deployment project is sponsored by NICI EPv6 R&D Division. The results of this paper can be shared with the person who attempts to deploy an EPv6-based SIP VoIP environment.
Effect of coplanar probe pad design on noise figures of 0.35 mu m MOSFETs
(2000-07-20)
Su, CY
;
Chen, LP
;
Chang, SJ
;
Huang, GW
;
Ho, YP
The effects of different coplanar ground-signal-ground (GSG) probe pads on the noise figure characteristics of submicron MOSFETs are presented. Devices with top-level metal as probe pads shielded by grounded bottom-level metal possess the most appropriate probe pad structure for characterising the noise performance of MOSFETs. Equivalent circuits of the probe pads are used to explain the different noise behaviours.
Effect of mechanical properties using different filler metals on wide-clearance activated-diffusion-brazed Ni-based superalloy
(2000-12-01)
Su, CY
;
Chou, CP
;
Chang, WJ
;
Liu, MH
;
機械工程學系
The investigation of mechanical properties and failure mechanism of activated-diffusion-brazed (ADB) joints in IN-738 plate were conducted. Joints of this type, which had wide clearance, were formed using the brazing alloys Nicrobraz 150 and DF4B, The microstructural characterization showed that chromium borides with a blocky morphology were present in joints associated with the two brazing alloys. A major difference in matrix phase chemistry was observed, however, for the two brazing alloys, e.g., an Ni-B eutectic phase was observed in Nicrobraz 150, but DF4B exhibited a coarsened gamma prime (gamma) phase and an absence of a nickel boride matrix phase, Results of tensile test showed that ADB specimens using DF4B brazing alloy exhibited 95% nominal tensile strength of IN-738 base materials. Fracture cracks in the joint area mere initiated and confined to dispersed chromium boride sites. However, tensile test of ADB specimens using Nicrobraz 150 showed poor tensile properties at all testing temperatures, and their fractures were initiated at a brittle nickel boride site and propagated along the weak-bonded interface between the Ni-B eutectic phase and base materials.
Low computational complexity enhanced zerotree coding for wavelet-based image compression
(2000-11-01)
Wu, BF
;
Su, CY
;
電控工程研究所
;
Institute of Electrical and Control Engineering
The embedded zerotree wavelet (EZW) algorithm, introduced by J.M. Shapiro and extented by A. Said and W.A. Pearlman, has proven to be a computationally simple and efficient method for image compression. In the current study, we propose a novel algorithm to improve the performance of EZW coding. The proposed method, called enhanced zerotree coding (EZC), is based on two new techniques: adaptive multi-subband decomposition (AMSD) and band flag scheme (BFS). The purpose of AMSD is to change the statistics of transformed coefficients so that the coding performance in peak signal-to-noise ratio (PSNR) can be elevated at a lower bit rate. In addition, BFS is used to reduce execution time in finding zerotrees. In BFS the tree depths are controlled, therefore, many unnecessary comparison operations can be skipped. Experimental results show that the proposed algorithm improves the performance of EZW coding and requires low computational complexity. In addition, the property of embedded coding is preserved, which enables a progressive transmission. (C) 2000 Elsevier Science B.V. All rights reserved.
Microstructural characterisation of transient liquid phase zone of activated diffusion brazed nickel base superalloy
(1999-03-01)
Su, CY
;
Chou, CP
;
Wu, BC
;
Lih, WC
;
機械工程學系
Microstructural investigations of activated diffusion brazed (ADB) joints in IN738 plate were conducted. Joints of this type, which had wide gaps, were formed using the brazing alloys Nicrobraz 150, BRB, and DF4B. Tests on the wettability of the brazing alloys when associated with an IN738 surface showed that a slight degree of wetting was associated with a rapid onset of isothermal solidification and conversely a heavy degree of wetting was associated with a relatively low rate of isothermal solidification. The microstructure of the joint area was characterised using a scanning electron microscope and an electron probe X-ray microanalyser (EPMA). These showed that borides with a blocky morphology were present in joints associated with all three brazing alloys examined. A major difference in matrix phase chemistry was observed however for th three brazing alloys, e.g. an Ni-Ni3B eutectic phase was observed in Nicrobraz 150, but DF4B and BRB exhibited a coarsened gamma prime (gamma') phase and an absence of a Ni3B matrix phase.
NCTU SLT: A socket-layer translator for IPv4-IPv6 translation
(2005-10-01)
Chen, WE
;
Su, CY
;
Lin, YB
;
資訊工程學系
;
Department of Computer Science
Based on Bump-In-the-API (BIA) architecture, this letter proposes a Socket-layer Translator called NCTU SLT that translates IPv4 applications to IPv4/IPv6-capable applications on dual-stack hosts. Like previously proposed approaches, NCTU SLT can translate NAT-friendly applications (e.g., HTTP and TELNET) without modifying the source codes of the IPv4 applications. Furthermore, NCTU SLT has the advantages over the previous approaches for translating non-NAT friendly applications (i.e., SIP,and FTP).
Plasma transferred are repair welding of the nickel-base superalloy IN-738LC
(1997-10-01)
Su, CY
;
Chou, CP
;
Wu, BC
;
Lih, WC
;
機械工程學系
Plasma transferred are welding (PTA) has been considered a promising process tea restore worn areas of land-based gas turbine blades and vanes. The objective of this investigation was to study the effect of PTA welding on the repairing of IN-738LC superalloy components, Tensile tests were conducted on specimens welded with various combinations of parameters, Room temperature, 760 degrees C, and 980 degrees C were selected Its tensile test temperatures, High-temperature phase transformed, during solidification, were identified by differential thermal analysis (DTA), The weld-pool shapes and microstructures of welded specimens prepared by various welding parameters were evaluated by optical metallography (OM), a scanning electron microscope (SEM) equipped with energy dispersive x-ray spectrometer (EDS), and microhardness testing. Results of this study showed that PTA welded specimens exhibited 96% nominal tensile strength of IN-738LC base materials, Specimen failure was observed predominantly in the base materials instead of in the heat-affected zone (HAZ) for gas tungsten are weld (GTAW) repair weldments, IN-738LC is considered susceptible to weld cracking during fusion welding; however, using a low-input heat repair welding process (PTA), cracking susceptibility could be minimized by the optimized welding parameters.
Total synthesis of (+/-)-nudenoic acid
(2000-06-02)
Ho, TL
;
Su, CY
;
應用化學系
;
Department of Applied Chemistry