基于海明编码的EEPROM数据存取功能的实现

针对工业现场对大容量数据存储空间及数据高可靠性的要求,基于单片机的IIC接口,设计了硬件电路和软件读写程序,实现了利用8片24LC512扩展单片机外部EEPROM存储空间的目的.并结合海明码的纠错能力,对数据先编码存储、后解码读取以提高数据的可靠性.现场应用验证,此设计可以实现4 Mbit空间数据的存取,数据准确可靠.     

Labelling accuracy in Tasmanian seafood: An investigation using DNA barcoding

Mislabelling of seafood products has been documented in numerous countries for over three-quarters of a century. With a trend towards increased consumption of seafood, the informed consumer demands accurately labelled products that provide full disclosure of composition. DNA barcoding can be used to accurately identify a seafood product to species based on its genetic signature, and so provides a means to test the authenticity and accuracy of seafood labelling. This can be especially useful for products such as fillets which have few or no unambiguous identifying characters, and can easily be mislabelled. We investigated labelling accuracy in seafood retailers in Tasmania, Australia. Thirty-eight seafood products were obtained from seafood retailers, sequenced for the barcoding gene region cytochrome oxidase subunit 1(CO1), and subsequently identified to species level by querying GenBank and Barcode of Life Data Systems (BOLD) DNA sequence records. Results were compared with standard fish names (SFN) prescribed under the Australian Fish Names Standard (AFNS) and FishBase. Of the 38 samples, none were deemed to have been mislabelled under Australian regulation, although in some cases naming discrepancies and ambiguity may cause confusion for some consumers. Our work, while reflecting high standards in Tasmanian seafood, highlights the need for mandatory standard labelling across all seafood products so as to eliminate any possible misrepresentation.     

Research on perfect dyadic binary sequence pair

In this paper, the perfect dyadic binary sequence pair with one-value dyadic correlation functions is presented. That is, the perfect dyadic binary sequence pair is a perfect discrete signal, for its dyadic relative function is δ-function. The transformation features and some existing admissibility conditions of perfect dyadic binary sequence pair are discussed, and the properties for this kind of code in Walsh transformation spectrum and weight spectrum are also analyzed. From above, It is found that the perfect dyadic binary sequence pair can easily differentiate from its dyadic shifting. So these good signals can used in engineering as synchronization code, multi-user code and so on.     

Investigation of uplink radio resource management schemes for multi-services in TDD-CDMA systems employing smart antennas

In this paper, a theoretical analysis of Time Division Duplex-Code Division Multiple Access （TDD-CDMA） uplink capacity constraint is presented when employing the smart antenna techniques. The evaluation formulations of capacity and load for multi-services are proposed. In order to maximize the throughput, the objective of optimization is proposed, and an advanced uplink resource management algorithm is developed. The proposed algorithm based on the least interference admission control scheme focuses on the maximum throughput for the circuit switched multi-services. The simulation results show that the proposed strategy has a significant improvement in throughput when the optimum admission control threshold is set.     

A novel Variable-Length Code for robust video coding

A novel Variable-Length Code （VLC）, called Alternate VLC （AVLC）, is proposed in this letter, which employs two types of VLC to encode source symbols alternately. Its advantage is that it can not only stop the symbol error propagation effect, but also correct symbol insertion errors and avoid symbol deletion errors, so the original sequence number of symbols can be kept correctly, which is very important in video communication.     

Structured inspections of code

Cleanroom programming and code inspections independently provide evidence that it is more efficient to postpone the testing of code to a later stage than is usually done. This paper argues that an additional gain in quality and efficiency of development can be obtained by structuring inspections by means of an inspection protocol. The written part of such a protocol is prepared by the programmer before the inspection. It is modelled on Floyd's method for the verification of flowcharts. However, the protocol differs from Floyd's method in being applicable in practice. Structured inspections gain this advantage by not attempting to be a proof; they are no more than an articulation of existing forms of inspection. With the usual method of structured programming it may be difficult to prepare the inspection protol. On the other hand, ‘assertion-driven programming’ (of which an example is included in this paper) not only facilitates protocol preparation, but also the coding itself.     

基于LV-BPL传输的Internet宽带接入系统研究

宽带低压电力线（LV-BPL）通信是一种重要的Internet接入技术,基于数字喷泉码与正交小波包编码调制提出了一种新的LV-BPL物理层系统模型。系统采用数字喷泉码作外码,块编码作内码,按块编码调制（BCM）映射到正交小波包调制时频平面。由于小波包稳定的正交性、自由的时频铺砌,数字喷泉码与码率无关的性质及BCM抗脉冲干扰的特点,系统在LV-BPL信道具有比编码DFT-OFDM更好的性能。     

奇异数据类型的编译支持

专用处理器,如DSP等,因主要支持特定应用,其指令集往往只支持有限的数据类型。在采用高级语言为其编程时,若采用了处理器不支持的奇异数据类型,编译器必须在保持语义的前提下将其转化为处理器支持的一段指令。该文提出了一种在VLIW DSP编译器中实现对奇异数据类型的处理的方法,包括对含有奇异数据类型的中间代码的注释、调度依赖关系的计算、寄存器分配的改进。该类方法对编译器的改动相对较小,效率较高。     

A large class of binary ZCZ sequence families constructed by period doubling

In an Approximately Synchronized Code Division Multiple Access （AS-CDMA） communication system, a family with large number of Zero Correlation Zone （ZCZ） sequences is desired, which can satisfy the rapid increase of users. This paper presents a method to generate a （2L,2M, ZCZ＇）-ZCZ sequence family from an original （L,M,ZCZ）-ZCZ sequence family, where ZCZ＇ = ZCZ if ZCZ is even and ZCZ＇ =ZCZ - 1 if ZCZ is odd. This method can also recursively act on a ZCZ sequence family to construct a series of ZCZ sequence families with large sequence number and zero correlation zone length identical to or one less than that of original ZCZ sequences.     

A class of band-limited chip waveforms for DS-CDMA systems

In Direct Sequence Code Division Multiple Access （DS-CDMA） systems, the chip waveform affects the implementation, system bandwidth, envelope uniformity, eye pattern and Multiple user Access Interference （MAI）. In this paper, based on an elementary density function of a second order polynomial, a class of second order continuity pulses is proposed. From this class of pulses, we can find some members having faster decaying rate, bigger eye opening, more uniform envelope and stronger anti-MAI capability than the Nyquist waveform. The normalized-bandwidth-pulseshape-factor product, the decaying rate of the tail of the time waveform, the opening of the eye diagram, and the envelope uniformity of the second order continuity pulses are addressed in the paper that provide the basic information for the selection of the chip pulse for CDMA systems.