• Title/Summary/Keyword: addition and subtraction

Search Result 211, Processing Time 0.025 seconds

Time-Division-Multiplexing Tertiary Offset Carrier Modulation for GNSS

  • Cho, Sangjae;Kim, Taeseon;Kong, Seung-Hyun
    • Journal of Positioning, Navigation, and Timing
    • /
    • v.11 no.3
    • /
    • pp.147-156
    • /
    • 2022
  • In this paper, we propose Time-Division-Multiplexing Tertiary Offset Carrier (TDMTOC), a novel GNSS modulation based on Tertiary Offset Carrier (TOC) modulation. The TDMTOC modulation multiplexes two three-level signals (i.e., -1, 0, and 1) while crossing over time, and is a type of TOC modulation designed specifically for signal multiplexing. The proposed modulation generates TDMTOC subcarriers of two different phases by simply combining two Binary Offset Carrier (BOC) subcarriers by addition or subtraction. TDMTOC has better correlation and spectral properties than conventional BPSK, BOC, and MBOC modulation techniques, and has good power and spectral efficiency since it can multiplex signals without power loss similar to time division multiplexing. To prove this, we introduce the multiplexing process of TDMTOC, and compare TDMTOC with Binary Phase Shift Keying (BPSK), BOC, Composite BOC (CBOC), and Time Multiplexed BOC (TMBOC) that are currently serviced in GNSS by simulations of various aspects. Through the simulation results, we prove that TDMTOC has better correlation property than modulations currently used in GNSS, less intersystem interference due to its wide spectrum property, and robustness in multipath and noise channel environments.

Low-complexity de-mapping algorithms for 64-APSK signals

  • Bao, Junwei;Xu, Dazhuan;Zhang, Xiaofei;Luo, Hao
    • ETRI Journal
    • /
    • v.41 no.3
    • /
    • pp.308-315
    • /
    • 2019
  • Due to its high spectrum efficiency, 64-amplitude phase-shift keying (64-APSK) is one of the primary technologies used in deep space communications and digital video broadcasting through satellite-second generation. However, 64-APSK suffers from considerable computational complexity because of the de-mapping method that it employs. In this study, a low-complexity de-mapping method for (4 + 12 + 20 + 28) 64-APSK is proposed in which we take full advantage of the symmetric characteristics of each symbol mapping. Moreover, we map the detected symbol to the first quadrant and then divide the region in this first quadrant into several partitions to simplify the formula. Theoretical analysis shows that the proposed method requires no operation of exponents and logarithms and involves only multiplication, addition, subtraction, and judgment. Simulation results validate that the time consumption is dramatically decreased with limited degradation of bit error rate performance.

A Study on the Articulation between Kindergarten and 1st Grade in Mathematics Education (유치원과 초등 1학년 아동의 수학 교육 연계에 관한 연구)

  • 김숙자;권영례;신인선;김상미
    • Education of Primary School Mathematics
    • /
    • v.4 no.1
    • /
    • pp.1-17
    • /
    • 2000
  • The purpose of this study is to analyze the articulation between the kindergarten and 1st grade in mathematics education. for this purpose, the problems of this study selected as follows :(ⅰ) What is the mathematical concepts related between the kindergarten curriculum and the 1st grade curriculum\ulcorner (ⅱ) How is the mathematics classroom in the kindergarten and 1st grade\ulcorner (ⅲ) Which instructional materials are used in the kindergarten and the 1st grade\ulcorner (ⅳ) What is the new direction of articulation between the kindergarten and first grade in mathematics education\ulcorner The results of this study are as follows : (ⅰ) According to examining each curriculum the focus is on understanding the basic concepts of number in the kindergarten, on the concepts of number, addition and subtraction in the 1st grade. (ⅱ) By being analyzed the mathematics classrooms of the kindergarten and the 1 st grade, it is different the focus of lessons or the teaching strategies. (ⅲ) As a result of analysing the teaching plans in the kindergarten and the survey in the first grade teachers, used instructional materials are manipulative ones. While mainly used materials are puzzles and blocks in kindergarten, a paduk stone, number cards, sankagi are used in 1st grade. (ⅳ) Finally, we propose the direction of articulation between the kindergarten and 1st grade in mathematics education.

  • PDF

A fuzzy model of human performance for VDU workers (VDU작업자의 작업수행도에 대한 퍼지모형)

  • ;;;神代雅晴
    • Journal of the Ergonomics Society of Korea
    • /
    • v.14 no.1
    • /
    • pp.97-104
    • /
    • 1995
  • The widespread use of VDU has improved the efficiency of information transmission between man and machine, but has caused new occupational health and ergonomics problems. In this study, we tried to construct a fuzzy hyman performance model of VDU workers in Korea. Fuzzy inferences of human perfor- mance are obtained from the fuzzy inference rule with the job difficulty, CFF, SACL, Type A. and the degree of concentration in VDU work. Eight healthy female undergraduate students at Kyungnam university for subjects aged 20 to 23 years were examined in this experiment. They calculated continuous addition, subtraction, and multiplication of 1 or 2 digit numbers that were produced randomly on the CRT. Subjects peoformed two types of a numeric operation, which easy and difficult work produced 400 and 600 problems within a 40 minute work session, respectively. Subjects were tested over two workdays according to the type of work(easy and difficult) consisting of four 40 minutes work sessions in the morning. Each work lasted for five minutes with a ten minutes rest break. 117 fuzzy inference rules were obtained from the experimental data. The value of consequent part was obtained by a descent method. The difference between real human error and estimated value of fuzzy inference was $1.8075{\pm}1.8591%(M{\pm}SD)$. The difference in easy and diffcult works were $2.69{\pm}2.13%$ and $0.92{\pm}0.93%$, respectively.

  • PDF

A Study on the Operation in Terms of Unit (단위 측면에서 연산에 관한 소고)

  • Roh, EunHwan;Kang, JeongGi;Jeong, SangTae
    • East Asian mathematical journal
    • /
    • v.30 no.4
    • /
    • pp.509-526
    • /
    • 2014
  • The mathematics has moved toward the independence from unit. However, is this tendency also kept up in teaching and learning mathematics? This study starts from this question. We have illuminated this question in respects of a character of unit operation, an essential probability of unit operation and a didactical application of unit. As results, addition and subtraction are operations on identical objects and the result of operation does not also get out of operation's object. On the other hand, multiplication and division are operations on both identical objects and different objects. And the result of operation can generate new unit. We proposed a hypothesis which multiplication and division are transcendental operations from this analysis. The unit operation is not possible essentially. It seems only like unit operation is possible superficially by operational definition on unit. We could discuss on a didactical application of unit from above analysis. And we could deduct implications that the direction of developing mathematic does not necessarily match with the direction of teaching and learning mathematics.

Fourier-Transform Infrared and Calorimetric Studies about the Influence of Tacticity of Poly(methyl methacrylate) on the Compatibility with Poly(ethylene oxide)

  • John, Eun-Sook;Jeon, Seung-Ho;Ree, Taik-Yue
    • Bulletin of the Korean Chemical Society
    • /
    • v.10 no.2
    • /
    • pp.123-128
    • /
    • 1989
  • Calorimetric study in conjunction with Fourier-transform infrared (FTIR) spectroscopic study was carried out on the blends of poly(ethylene oxide) (PEO) with isotactic, atactic and syndiotactic poly(methyl methacrylate) (i-, a-, and s-PMMA). From the differential scanning calorimetric (DSC) measurements, the three types of blends show a depression of the melting temperatures. This indicates that PEO is compatible with i-, a-, and s-PMMA. But the largest melting point depressions of PEO are always found in the blends with s-PMMA. For PEO/a-PMMA and PEO/s-PMMA, the degree of crystallinity as a function of composition deviates substantially from that of the ideal blend in which no interaction between the components exists. The FTIR spectra of all three types of blends are recorded. In order to observe the microstructural changes of PEO in blends, we analyzed the spectra using digital weighted subtraction and addition techniques. It was concluded that the microstructures of PEO are strongly perturbed by the PMMA's. Among these blends PEO microstructure in PEO/s-PMMA blends is most greatly influenced. It indicates that the blending is most preferred with s-PMMA than a- and i-PMMA. It can be explained on the basis of the molecular structure of PMMA's.

Vision-based garbage dumping action detection for real-world surveillance platform

  • Yun, Kimin;Kwon, Yongjin;Oh, Sungchan;Moon, Jinyoung;Park, Jongyoul
    • ETRI Journal
    • /
    • v.41 no.4
    • /
    • pp.494-505
    • /
    • 2019
  • In this paper, we propose a new framework for detecting the unauthorized dumping of garbage in real-world surveillance camera. Although several action/behavior recognition methods have been investigated, these studies are hardly applicable to real-world scenarios because they are mainly focused on well-refined datasets. Because the dumping actions in the real-world take a variety of forms, building a new method to disclose the actions instead of exploiting previous approaches is a better strategy. We detected the dumping action by the change in relation between a person and the object being held by them. To find the person-held object of indefinite form, we used a background subtraction algorithm and human joint estimation. The person-held object was then tracked and the relation model between the joints and objects was built. Finally, the dumping action was detected through the voting-based decision module. In the experiments, we show the effectiveness of the proposed method by testing on real-world videos containing various dumping actions. In addition, the proposed framework is implemented in a real-time monitoring system through a fast online algorithm.

A Design and Implementation of 32-bit RISC-V RV32IM Pipelined Processor in Embedded Systems (임베디드 환경에서의 32-bit RISC-V RV32IM 파이프라인 프로세서 설계 및 구현)

  • Subin Park;Yongwoo Kim
    • Journal of the Semiconductor & Display Technology
    • /
    • v.22 no.4
    • /
    • pp.81-86
    • /
    • 2023
  • Recently, demand for embedded systems requiring low power and high specifications has been increasing, and RISC-V processors are being widely applied. RISC-V, a RISC-based open instruction set architecture (ISA), has been developed and researched by UC Berkeley and other researchers since 2010. RV32I ISA is sufficient to support integer operations such as addition and subtraction instructions, but M-extension should be defined for multiplication and division instructions. This paper proposes an RV32I, RV32IM processor, and indicates benchmark performance scores compared to an existing processor. Additionally, A non-stalling method was proposed to support a 2-stage pipelined DSP multiplier to the 5-stage pipelined RV32IM processor. Proposed RV32I and RV32IM processors satisfied a maximum operating frequency of 50 MHz on Artix-7 FPGA. The performance of the proposed processors was verified using benchmark programs from Dhrystone and Coremark. As a result, the Coremark benchmark results of the proposed processor showed that it outperformed the existing RV32IM processor by 23.91%.

  • PDF

A New Design Method for One-Dimensional and Two-Dimensional Maximally Flat FIR Filters with Zero-Phase (위사차가 없는 1차원 및 2차원 Maximally Flat FIR 필터의 새로운 설계 방법)

  • 박종연;장목순
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.19 no.12
    • /
    • pp.2458-2467
    • /
    • 1994
  • This paper proposes a new design method for obtaining the impulse responses which satisfy the prescribed conditions designing for maximally flat FIR lowpass filters and highpass filters. The bandpass filters and band-reject filters have been directly derived from the addition and subtraction of impulse responses of a lowpass filter and a highpass filter. The two-dimensional maximally flat FIR lowpass filter, highpass filters, bandpass filters and band-reject filters with zero-phase have been designed by transforming the impulses of the one-dimensional filters designed in this research, which do not destroy lines and edges at the image signal processing.

  • PDF

An Analysis of Students' Understanding of Operations with Whole Numbers and Fractions (자연수와 분수 연산에 대한 학생들의 이해 분석)

  • Kim, Kyung-Mi;Whang, Woo-Hyung
    • The Mathematical Education
    • /
    • v.51 no.1
    • /
    • pp.21-45
    • /
    • 2012
  • The purpose of the study was to investigate how students understand each operations with whole numbers and fractions, and the relationship between their knowledge of operations with whole numbers and conceptual understanding of operations on fractions. Researchers categorized students' understanding of operations with whole numbers and fractions based on their semantic structure of these operations, and analyzed the relationship between students' understanding of operations with whole numbers and fractions. As the results, some students who understood multiplications with whole numbers as only situations of "equal groups" did not properly conceptualize multiplications of fractions as they interpreted wrongly multiplying two fractions as adding two fractions. On the other hand, some students who understood multiplications with whole numbers as situations of "multiplicative comparison" appropriately conceptualize multiplications of fractions. They naturally constructed knowledge of fractions as they build on their prior knowledge of whole numbers compared to other students. In the case of division, we found that some students who understood divisions with whole numbers as only situations of "sharing" had difficulty in constructing division knowledge of fractions from previous division knowledge of whole numbers.