• Journal of Korean Society for Geospatial Information Science
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• v.15 no.3
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• pp.87-96
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• 2007

In the numerical cadastral surveying field, the cadastral surveying would be measured with the Total Station surveying (electronic plane table surveying) system that consist the Total Station for surveying and the computing system for recording and editing the measured coordinates data by the TS. This study would suggest the advanced method, which is used on the RTK-GPS instead of TS for surveying and the computing system for handling the coordinates data and mapping. As a result of this study, although the measurement accuracy of the RTK-GPS and TS surveying make no greate difference, the suggested method reduces the cost of time and work force with the TS surveying. Besides, the new survey method would be more efficient due to directly handling the data and mapping in the field.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.4
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• pp.406-414
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• 2004

In Gerotor pump, the pressure pulsations which occur due to the pump geometry result in vibration and noise of pump elements as well as cavitation in hydraulic system when the chambers of gerotor enter the delivery port and leave the suction port. Therefore it is important to study on the pressure pulsations before design and analysis of characteristics in Gerotor pump. In this paper, to reduce the unnecessary pressure pulsations, the port plate of Gerotor pump is designed based on the notch of the vane pumps and the relief grove of the piston pumps. The theoretical analysis of the pressure pulsations is performed in consideration of design parameters of the port plate which include each port positions and groove width and operating conditions which include rotational velocity and delivery pressure.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.21 no.3
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• pp.209-214
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• 2003

The tasks in the cadastral field are being carried out by the aid of Parcel Based Land Information System which is equipped with both graphical and textual information acquired by the Cadastral Map Computerization Project. This have the purpose to present efficient surveying method as analyzing the accuracy about the field map We can also avoiding the drafting error caused by graphical cadastral and technical error including scale and contraction error as inverting an existing surveying system to the computer surveying system with this data.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.3
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• pp.1-9
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• 2016

The purpose of this study is to examine the shear strength and structural performance of DH-Beams. The DH-Beam construction method uses thin steel plates as form-works and structural elements. Steel plates and rebars for DH-Beams were prefabricated at factory and then erected before casting concrete at construction sites. In this study, the contribution of steel plates to the shear strength of DH-Beam was evaluated since the plates were expected to work as reinforcements. Five test specimens were made for experimental and analytical studies. They consisted of two DH-Beams for the positive loading test and two DH-Beams for the negative loading test and a RC beam for the comparison purpose. Test results on DH-Beams were compared with design equations and the RC beam test result. It was proven that DH-Beams demonstrated the good shear behavior showing sufficient strengths and deformation capacities. Nonlinear analyses with test specimens were also used to evaluate the contribution of DH plates to strengths. Analytical models included various cases such as beams with lateral plates only or beams without any plates. These analyses also showed that steel plates can contribute to the enhancement of shear strength of DH-Beams. Based on experimental and analytical studies, it was concluded that steel plates of DH-Beams can be used as good shear reinforcements.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.126-128
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• 2018

왜(倭)는 15-20회의 견당사를 파견하였는데, 838년 견당사의 항해와 관련해서는 이에 동승한 엔닌(円仁)이 "입당구법순례행기"를 남김으로써 그 항해의 전말이 상세하게 남아 있다. 이 기록에서 특히 관심을 끄는 것은 엔닌이 승선한 견당사선이 중국의 양주 해릉현 연안에 표착하였을 당시 기사에 언급된 정체를 알 수 없는 '누아'에 관한 기사다. 여기에서 누(?)는 ?(괭이 누), ?(김맬 누)와 같으며, '낫'이나 '호미'를 뜻하지만, 아는 중국이나 일본에서 전혀 사용되지 않는 한자어여서 글자 그대로 무엇을 의미하는 지가 불분명하다. 따라서 누아가 무엇을 의미하는지에 대해 선저 결구, 횡강력재, 피수판 등 여러 견해가 제기된 바 있다. 이 논문은 "입당구법순례행기"에 기록된 선박부재 '누아'가 무엇인지 살펴본 것이다. 먼저 "입당구법순례행기"의 여러 편역본에 '누아'가 어떻게 번역 내지 해석되고 있는지 살펴보고, 왜의 견당사선의 선형이 어땠을 지를 검토한 뒤, 이 선형의 견당사선이었을 경우 '누아'는 선박의 어떤 부재였을지를 추정해 보고자 한다. 특히 누아를 '피수판'으로 보는 최근식의 견해와 '??(진복)'의 오기로 보아 '횡강력재'로 보는 허일의 견해를 비판적으로 재검토할 것이다. 결론적으로 누아는 녹복(??)(기댈 녹, 들보 복, 즉 지지용 들보)의 오기로 판단했다. 또한 일본학자들이 견당사선을 '중국형 정크선'으로 추정하는 것과는 달리, 중국형 선박에는 선저와 상부에 횡강력재가 각각 독립해 있는 부재가 없는 것으로 보아 견당사선은 화선형 선박이거나, 한선형 선박일 것으로 추정하였다. 결론적으로 엔닌이 언급한 누아는 화선형 선박일 경우 船梁(후나바리), 한선형 선박일 경우 가룡목과 가목으로 볼 수 있다.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.2
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• pp.24-30
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• 2016

An experimental study for the characteristics of the thrust-vectoring of a sonic jet utilizing the coanda flap installed at a rectangular nozzle exit is performed. Two side plates are installed at both sides of the flap to decrease the three dimensional effects of the jet on the flap surface. Schlieren flow visualizations and quantitative measurements of the deflection angle of thrusting vector show that the side plates are able to delay the separation of the jet at the downstream of the flap surface. Substantial increase in the deflection angle of the jet as high as $72^{\circ}$ and small thrust loss as low as 7% are obtained by the present thrust-vectoring technique using the side plates.

• Conservation Science in Museum
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• v.25
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• pp.27-34
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• 2021

A Goryeo-era mother-of-pearl-inlaid incense box in the collection of the National Museum of Korea, a major example of Goryeo dynasty cultural heritage, presents a comprehensive view of the production techniques and aesthetic expressions of its time. This study investigated the type of wood and the techniques used to make the framework of the box, knowledge that was necessary for its restoration. It also examined anatomical characteristics of the shell providing the mother-of-pearl. The incense box was found to be made of cedar, which suggests that there was trade in cedar with Japan. A band was attached to the lower portion of the lid by applying what the author describes as a "wrinkle-bending" technique at the corners. Wooden pegs were used to combine the top and side panels, probably for more efficient use of the thin wooden boards. The investigation of the anatomical features of the mother-of-pearl inlay identified a laminated structure of thin plates. These features are observed in certain shellfish, and further study would be required to accurately identify the type of shell.

• Journal of Aquaculture
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• v.4 no.1
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• pp.31-66
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• 1991

This paper deals with the reproductive ecology e.g., number of the pre-spawning moults, morphological characteristics of the pre-spawning moult the common moult, daily ration druing a molting cycle mating behavior, structures of spermatozoa and spermatophore, structure of vas deferens, mechanisms of the oviposition and brooding into the egg-chambers, a suitable time for the artificial mating and fertilization, time sequence of the oviposition and brooding into egg-chambers from the copulation, responses to temperature and chlorinity on the egg development and hatching, effect of temperatures on duration of egg development, physical mechanism of the egg hatching, to make an attempt for the artificial spawning and brooding to establish a suitable system of the artificial seedling-production for the aquaculture. 1. Females molted commonly $8{\~}10$ times at an interval of $17{\~}18$ days at $28^{\circ}C,\;3.26\~4.35\%_{\circ}$ while the prespawning moltings were $4{\~}5$ times at an interval of $13{\~}14$ days. The suitable state for artificial copulation was within 14 hours elapsed from the prespawning moltings (most suitable state was within 8 hours). Males discharged a gelatinous spermatophore and placed it on the females sternum during copulation. Oviposition was seen $6{\~}17$ hours after copulation. External fertilization was considered to take place at oviposition. Fertilized eggs held in egg-chambers forming between pleopods were about $5000{\~}6000$ in females those sizes about 6.5 cm in body length. 2. Eggs immediately after oviposition were elliptic shape, measuring $0.58{\times}0.48$ mm up to hatching. Their sizes increased with egg development and finally reached $0.85{\times}0.54$ mm up to hatching. The relationship between the long axis of the egg(Y in U) and days elapsed(X) was expressed as Y= 5.60194 + 0.007358X. The eggs performed superficial cleavage and their cleavage furrows became visible at the 4-daughter-nucleus stage. The eggs showed normal development up to hatching at water temperature range of $22{\~}30^{\circ}C$ (optimum temperature : $26{\~}28^{\circ}C$) and at chlorinity range of $0.00\~6.64\%_{\circ}$ (optimun chlorinity : $2.21{\%}_{\circ}$). The relationship between incubation period (Y in days) and water temperature(X in $^{\circ}C$) could be expressed as Y= 50.803-1.3555X. The eggs hatched $12{\~}13$ days after oviposition at $28.0{\~}28.6^{\circ}C$ 3. The pre-spawning moltings were appreciably different in the morphologic structure from those of common moltings. Breeding setae and dresses were formed on the thoracic regions, abdominal epimerae and the bases of the first to fourth pleopods in order to prepare and support oviposition, transfering and supporting eggs in egg-chambers up to hatching. These supplementary breeding organs were observed only at reproductive seasons.