This paper describes a Frequency Shift Keying (FSK) modulator and demodulator and the experimented underwater data ommunication equipment to transfer the analog echo signal in real-time from an underwater vehicle to the mother ship. The system consists of an echo signal transfer unit equipped to the vehicle and an ultrasonic receiver equipped on the ship. The former includes an ultrasonic transceiver unit of 180kHz for echo detection and a continuous wave transmitter of 50kHz with a FSK modulator for echo transmission to the ship. The latter includes an ultrasonic receiver of 50kHz and the FSK demodulator. The results of experiment are as follows. 1. The characteristics of the FSK modulating and demodulating circuits designed with the use of C-MOS IC 4046 was good and confirmed its usefulness in underwater data communication system.2. The prototype ultrasonic transceiver unit shows profitable driving power while the pulse duration was short less than 3 msec, but it was found that the driving power is not sufficient while the long pulse duration or continuous wave is used. The gain of the ultrasonic receiver was 80 dB and the receiving bandwidth 700Hz (at - 3 dB point).3. It was found that the system designed by the author has some possibility to use in underwater echo transfer.4. At the FSK modulator, the widths of voltage and frequency which represent linearity were 3.5 V, 1600Hz, respectively, at the FSK demodulator 2.6 V, 700Hz, respectively.

The following demonstrates similarities between Japanese and Korean food culture. The facts have been discovered through the examination of records kept by Korean Communication Facilities and Japanese Envoys. Both countries used the numbers 7, 5, 3, in food treats. Both demonstrated Da do(茶道) style during banquet. Japanese Na-ra-dae(奈良臺) is similar to Korean Sue-bae-sang(壽杯床). Both countries had a Kan-ban(decorative table, 看盤) and Mi-soo(wine and someatables, 味數) during banquet. The composition of the table may be the same for both Korean Geo-sick-oh-kwa-sang and Japanese 3Jeup(soups) 15Che(dishes). Agasang is a Kan-ban(decorative table) of Choson's Da-do(茶道) style.

After the Japanese Invasion of Korea in 1592, correspondents of Chosun called on Japan twelve times, as a mission, from 1607 to 1811. The suite of Chosun Communication Facilities (correspondents) was composed of nearly 500 people including a senior envoy, a junior envoy, other envoyes, and cooks. After preparing traveling expenses, Sifts, foods, medicinal stuffs, and ginseng, they shipped people and freight in three passenger ships and three freighters. They departed from Pusan for Edo(Tokyo). There were 28 stop-overs on their way to Edo and the banquet was given for them at every stop. The arrangements of the table for each banquet were made up of 753 Seon(tables), 3Jeup(soups) and 15Che(dishes). 753Seon(tables) is Ganban(the table for decoration) and a substantial food reception was composed of 3Jeup(soups) and 15Che(dishes). 753Seon(tables) was called Dadopoong(the food of refreshment) style and this was the standard arrangement of the banquet table in Japan. It was comprised of 3Jeup(soups) and 15Che(dishes). On their way from Edo to Thusima Island, food was afforded to correspondents for later preparation and dining. The banquet that the master of Thusima Island gave was composed of the first and second style banquets. The first one was Chusun style and the second one was Japanese style.

CuO 및 C얘의 첨가가 BiNbO4 세라믹스의 고주파 유전특성에 미치는 영향을 조사하였다. CdO 첨가량이 증가함에 따라 소결밀도 및 품질계수는 감소하였고 소결온도가 증가하면 유전상수 및 품질계수는 증가하였다. BiNbO4에 CuO 및 CdO를 각각 0.03wt% 첨가한 시편을 960˚C에서 소결시 유전율 41.2, 품질계수(Q×f0) 6,500(at 5.6GHz), 공진주파수 온도계수 3ppm˚C의 우수한 고주파 유전특성을 얻을 수 있었다.

Food goods traded between Korea and Japan during the middle period of the Cho Sun era included Insam (Jinseng), rice, beans, honey, perilla oil, starch, adlay, walnuts, pine nuts, jujubes, hazelnuts, and dired chestnuts as exports ; and pepper as imports. The number of Japanese envoies that visited regularly was one thousand five hundred people a year. The receptions that were held for them during the middle period equaled those of the first term of the Cho Sun era, but these receptions were only held in Pu-san. The expense of daily meals was broken down into 8 grades ranging from \129,300 to 2133. The daily meals included Jo-ban (breakfast), Jo-seok-ban (breakfast and dinner), and Ju-jeom-shim (lunch) for the Japanese who visited regularly. During the course of a year, the total amount spent on daily meals was put at a billion won. The banquet style meals included Ha-seon-da-rye (a welcome tea party), Ha-seon-yeon (a welcome banquet), No-cha-yeon (a banquet that was held on the street), and Ye-dan-da-rye (a drink banquet that was held when silk was offered as a gift). It also included Byeol-yeon (a banquet out of the dordinary), Sang-seon-yeon (a farewell banquet), and Myong-il-yeon (a banquet that was held on a national holiday). The banquet style meals were composed of Ceon-tack (to set a table for dinner), Sang-hwa (a flower that was put on the food), Kwan-hwa (to offer a flower when a banquet was held), Ju-9-jan (the ninth wine glass), Dae-seon (meat), music, and Jung-bae-rye (a banquet that was held again after a banquet). The Cho Sun government held banquets forty five times for the Japanese, the food expense for the banquets was put at two hundred and thirty million won.

Food goods traded between Korea and Japan during the first term of the Cho Sun era included Omija (fruit of the Maximowiczia chinensis), Jat (pine nuts), Insam (Jinseng), rice, and beans as exports ; and pepper, sugar, and medicinal stuffs as imports. The trade between Korea and Japan was a result of Japanese envoies' visiting. The official number of Japanese envoies who had exchanges with Koreans were two thousand people a year. Once the Japanese entered Korea, they did not need to pay for their living expenses for the length of their visit because the Cho Sun government bore the whole expense. The Cho Sun government gave formal receptions to them, which included daily meals as well as banquet style meals. The daily meals included Jo-ban (breakfast), Jo-seok-ban (breakfast and dinner), and Ju-jeom-sim (lunch). Meals were served four times a day. The banquet style meals included Sam-po-yeon (a banquet that was held in Sam-po), Kyong-joong-young-jeon-yeon (a farewell banquet, and a welcome banquet that was held in Seoul), Jyu-bong-bae (to offer a guest a drink by day), No-yeon (a banquet that was held on the street), Kwol-nae-yeon (a banquet that was held within the Royal Court). It also included Ye-jo-yeon (a banquet that was held in Ye-jo), and Myong-il-yeon (a banquet that was held on a national holiday). The banquet style meals were composed of Ceon-tack (to set a table for dinner), Sang-hwa (a flower that was put on the food), Kwan-hwa (to offer a flower when a banquet was held), Ju-5-jan (the fifth wine glass), Dae-seon (meat), and music.

이동통신용 고주파 표면탄성파(SAW) 필터를 36˚Y-X LiTaO3압전기판과 IIDT 전극구조를 이용하여 제작하였다. 제작한 SAW 필터의 중심주파수는 주파수 응답 특성 측정 결과 설계한 중심주파수보다 낮아짐이 관찰되었다. 이러한 단점을 보완하고 미세한 주파수의 조절을 가능하게 하기 위해 SiNx 유전박막을 보호막으로 증착하여 이에 따른 주파수 특성 변화를 관찰하였다. SAW파장에 대한 SiNx 유전 박막의 두께비를 증가시킬수록 SAW 진행 속도가 증가하여, 제조한 필터의 중심주파수를 높게 이동시킬 수 있었다. 그러나 유전박막의 두께가 증가할수록 필터의 삽입손실이 증가하는 문제점이 존재하였다.