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        • 위성채널에서 대역폭 효율적인 MSK 시스템

          李明浩 청주대학교 산업과학연구소 1986 産業科學硏究 Vol.4 No.-

          In this paper, a model and analysis of Minimum Shift Keying (MSK) is compared with Offset QPSK (Quadrature Phase Shift Keying) for the satellite communication channel, a result of which shows that the theoretical maximum bandwidth efficiency of MSK is 2bps /Hz, the same as for QPSK and OQPSK. The requirement of filtering to perform minimum spectrum width and raised-cosine spectrum is presented while obtaining the condition of zero intersymbol interference for Offset QPSK and MSK system. For OQPSK and MSK signal, bath filtered for 0%, 50%, and 100% excess bandwidth raised cosine spectrum, they show that error rate performance versus receiver decision threshold unit input SNR is best for 100% excess bandwidth filtering. In addition, when carrier recovery- and coherent demodulation use the squaring phased-locked loop, error rate performance versus receiver input SNR provides a 3dE. advantage over detection of coherent FSK, and the effect of PLL phase error on bit error probability of MSK system is analysis. From the above results, MSK model is bandwidth-efficient modulation technique with zero intersymbol interference for the satellite communication channel.

        • Latin어의 음성학적 및 음운론적 고찰〔Ⅰ〕

          李明鎬 中央大學校 人文科學硏究所 1994 人文學硏究 Vol.21 No.-

          This study of Latin letters and their pronunciations on phonetical and phonologic level is both on the synchronic and diachronic dimensions. Classic Latin, elaborately promoted by the Classic Latin authors under the influences of the Greek civilization, is a written, literary and academic language. On the oral level, this language was polite and social one. In its golden age Classic Latin, though influenced by Greek, assures its proper simplicities and clearness in the letters and the pronunciations. As an elaborate written language, Classic Latin carries lots of important resources, necessary for studies on phonetic and phonological levels. Latin is chronologically delimited in certain characteristic ages : Archaic Latin(BC 6^c~BC First half of 3^c), Preclassic Lt.(BC Second half of 3^c~BC Early 1^c), Classic Lt.(BC Middle of 1^c~AD14), Postclassic Lt.(AD 15~End of 2^c), Late Lt.(AD200~Fa11 of Roman Empire) which is characteristic of the relation with christianity, which is a quasi-official faith in the Empire, consequently also in Romania, and throughout the Middle Age in Western World. Late Latin is the official language in the christianity through which it has been conserved down to date, and it is this Late Latin that has given the basis to the so-called Traditional Latin on which the IPA(international phonetic alphbet) is based. Folowing the fall of the Roman Empire emerged Romanic language(<Lt. lingua Romana(or Romanica)) which gave birth to Neo-latins(Italian, Spanish, French...)-which exterminated the linguistic Roman Empire survived even after the fall of the political Roman Empire. In this study the preponderance is put on Classic Latin, but it is inevitable that Traditional Latin should additionally be dealt, and Neo-latins are referred as far as they are required for references. Both Romanic and Neo-latins furnish this study with very important references in tracing the processes of phonetic and phonologic evolutions in Latin. In Latin, /u/ and /i/ (both vowels and semi-vowels or consonants) are very instable phonemes, and especially i has lots of influence on the contiguous sounds, rendering them palatalized. The affricates([t??, d??, ts, dz]), the palatalized 'n'([n]) and the chuintant([??]), all of which appear after Classic Latin, are the results of the influences(assimilational, analogical, or euphonic) related with the i. The said later born variants in Latin, whether conditioned or non-conditioned, have become parts of the Neo-latin phonemic systems. Meanwhile the [??], when it has very intensive frequency in Latin, is simply a conditioned allophone of /g/ and /n/ (sometimes of /m/), and which after all couldn't assure a position as a phoneme in Neo-latin phonemic systems.

        • 생활정보 라디오 텍스트에 관한 연구

          李明浩,鄭然湖 청주대학교 산업과학연구소 1991 産業科學硏究 Vol.9 No.-

          This paper analyzes several kinds of supporting service types of the next generation broadcasting system and investigates the RDS(Radio Data System). The RDS encoding and decoding system is constructed according to the standard specifications recommended by EBU(European Broadcasting Union). After constructing the experimental circuit, the effectiveness of the proposed method has demonstrated according to the following steps; 1) Investigating the analytical approach to the transmitting and receiving system for the RDS. 2) Replacing the transmitting and receiving circuits with the personal computers. 3) Analyzing the signals on the clock recovery circuit in the process of the clock recovery.

        • 熔接構造物等의 熱應力測定에 關한 硏究

          李明鎬 서울産業大學校 1980 논문집 Vol.13 No.1

          Recently, the thermal stress measurement becomes on issue because the welded elements such as especial boiler, turbine and high pressure vessel of atomic reactor are frequently used and they are worked at high temperature. That is why, in most case, thermal stress is a repeated thermal cycle phenomenon and often forms a cause of the breakage of machines. The present investigation found same relative difficulties in compensating method and adhesive method of the apparent strain value according to temperature by directly adhering high temperature strain gauge to material part at high temperature, 400℃ for the first time. In other words, this study made a comparison between principal value and experimental value of thermal stress for circle hole and round plate as a fundamental experiment. I think that we need mastery and experience for this experiment because there are lots of difficulties for the first time differently from the normal temperature gauge. I got a high good accurate results in this experiment of the thermal stress measurement through this paper.

        • 空洞現象의 計測에 關한 硏究

          李明鎬 서울産業大學校 1986 논문집 Vol.24 No.1

          Cavitation make a bad influence on all machinerys. In this report, used the method measuring the air bubbling nucleus in water of the cavitation water tank, the method measuring with laser Rays and the method inspecting the collapsing position and the collapsing strength of cavitation to measure the cavitation.

        • 軸流送風機內에서 發生하는 間隙流動現象에 關한 硏究

          李明鎬 서울産業大學校 1987 논문집 Vol.26 No.1

          This paper dealt with the relation between the flow from the clearance of the front part of impeller and the revolution stall. The flow from the clearance of the front part of impeller was shown to be different the cascade to be stoped from the cascade to be revolted and in low pressure blower, the flow to go with the revolution stall of low capacity was shown.

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