• The Korean Journal of Malacology
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• v.21 no.2 s.34
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• pp.95-105
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• 2005

Gonadosomatic index, reproductive cycle, spermatogenesis and first sexual maturity of Chlamys farreri were investigated by cytological and histological observations, from January 1998 to December 1999. The gonadosomatic index (GSI) rapidly increased in April and reached a maximum in May when seawater temperature rapidly increase. Then the GSI gradually decreased from June to August when spawning occur. Accordingly, monthly changes in the GSI in males coincide with the reproductive cycle. The spermatozoon of Chlamys farreri is the primitive type found in external fertilization species. The head of the spermatozoon is approximately $2.75{\mu}m$ in length including the acrosome measuring about $0.50{\mu}m$ in length, and its tail was approximately $20{\mu}m$, the axoneme of the tail flagellum consists of nine pairs of microtubules at the periphery and a pair at the center. Five spherical mitochondria around the centriole (the satellite body) appear in the middle piece of the sperm. The spawning period was from June to August and the main spawning occurs from July to August when seawater temperatures are greater than $20^{\circ}C$ The reproductive cycle of this species can be categorized into five successive stages; early active stage (January to March), late active stage (March to April), ripe stage (April to August), partially spawned stage (June to August), and spent/inactive stage (August to January). Over 50% of male scallops attained first sexual maturity between 50.0 and 60.0 mm in shell height, and 100% of those over 60.0 mm in shell height achieved maturity. Accordingly, we assume that male individuals begin reproduction at three years of age.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.6
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• pp.1-10
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• 2019

The wave motion inside the nozzle is known as one of the major damping elements of the rocket's combustion instability by it's aeroacoustic effects that result from the flow passage through the nozzle throat. These effects can be quantitatively evaluated by the nozzle admittance. In this study, one-dimensional linearized Euler equation was adopted to calculate the nozzle admittance, and trend analysis was performed depending on the nozzle's main design variables. As a result, when nozzle converging part shortens, it is verified that the frequency dependency of the nozzle admittance is decreased due to the widened frequency range with lowered longitudinal nozzle admittance. Also, admittance estimation using the short nozzle theory is not appropriate when the first tangential mode of the pressure perturbation arises.

• Journal of Korean Society of Forest Science
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• v.101 no.2
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• pp.203-212
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• 2012

This study aims to test presence of spatial autocorrelation of burn severity in Uljin and Youngduk areas burned in 2011. SPOT satellite images were used to compute the NDVI representing burn severity, and NDVI values were sampled for 5,000 randomly dispersed points for each site. Spatial autocorrelations of sampled NDVI values were analyzed with Moran's I and Variogram models. Moran's I values of burn severity in Uljin and Youngduk areas were 0.7745 and 0.7968, respectively, indicating presence of strong spatial autocorrelations. On the basis of Variogram and changes of Moran's I values by lag class, ideal sampling distance were proposed, which were 566-2,151 m for Uljin and 272-402 m for Youngduk. It was recommended to apply these ranges of sampling distance in flexible corresponding to Anisotropic characteristics of burned areas.

• Journal of Navigation and Port Research
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• v.28 no.3
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• pp.247-252
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• 2004

It's important to develop Metadata standard to manage a large of marine geospatial data such as observation, ocean survey, satellite image more effectively. If we use metadata in Marine GIS we can make sense marine geospatial data, make the most of marine dataset. International standard organization's work and NGIS's standard are a good example to illustrate metadata standard's importance. But we don't have metadata standard for marine dataset, so it's difficult to search and use geospatial data In this paper, we presented common marine metadata element, and composited metadata implementation schema. Finally we constructed marine GIS metadata editing tool..

• Journal of the Korean earth science society
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• v.27 no.7
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• pp.778-786
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• 2006

In Korea, the ozone profiles have been acquired by using ozonesonde at Pohang station of the Korea Meteorological Administration (KMA) since 1995. These ozone soundings were performed at 0500 UTC on a weekly basis (every Wednesday) in a clear sky. The ozonesonde is equipped with the model 5A ECC sensor, which is one of the most common ozonesonde systems. There have been no attempts to evaluate the Pohang ozonesonde profiles compared with satellite. This paper will provide the first evaluation results for the ozonesonde profiles against HALogen Occultation Experiment (HALOE) measurements over Korea. During 1995-2004 periods, a total of 450 and 188 ozone profiles were obtained from the ozonesonde measurements from HALOE measurements over Korea, respectively. Hence, a total of 34 coincident profile pairs are extracted. Among those total profiles, 26 profiles from ozonesonde are compared against nearly coincident HALOE measurements in time and space. For ozone profiles, the results of statistical analyses showed that the best agreement between two measurements occurs in the 20-25 km and 30-35 km region, where the mean and RMS percent differences are less than ${\pm}5$ and 14%, respectively. For temperature profiles, the mean and RMS percent differences in 20-25 km region are estimated to be about -0.1 and 1.7%, respectively. According to the scatter plots between two measurements, ozone data are strongly correlated each other above 20 km altitude range with more than 0.8 correlation coefficients. It is found that the altitude (pressure level) differences between two measurements would mainly lead to the discrepancy (over 40% below 18 km) below 20 km in ozone profiles.

• Journal of Broadcast Engineering
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• v.16 no.5
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• pp.797-800
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• 2011

The objective of MPEG Media Transport (MMT), which is on going standard, is to develop efficient delivery of media over packet based networks in an adaptive, progressive, download/streaming fashion over various IP based networks, including terrestrial, satellite and cable broadcast networks. In this paper we introduce utilization of signal strength information based on Cross Layer Design(CLD) to efficient multimedia delivery over wireless network in which in practice the wireless conditions can vary significantly. Many recent studies have shown that a significant improvement in wireless video throughput can be achieved by utilizing signal strength information on CLD [1][2]. Despite of its usefulness, however, it was difficult to employ signal strength information in rate adaptation applications due to different representation of signal strength information for each underlying wireless network. To that end, we proposed syntax and semantics of signal strength information in such a way that the information can be interpreted in the unified way. The proposed signal strength information was proposed for the MMT standardization.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.5
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• pp.570-576
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• 2015

3D visualization of navigation simulation is to visualize the environment conditions (e.g. nearby ships, dynamic characteristics, environment, terrain, etc) for any users on ships at sea. Realistic 3D visualization enables the users to be immersed to it and guarantees the reliability of the simulation. In particular, terrain visualization contains many virtual objects, so it is time and cost-intensive for object modelling. This paper proposes a 3D terrain visualization method that can be realized in a short time and with low cost by using the Unity 3D development tool. The 3D terrain visualization system requires bathymetric and elevation terrains, and Aids to Navigations (AtoNs) to be realized. It also needs to include 3D visualization objects including bridges, buildings and port facilities for more accurate simulation. Bathymetric and AtoN elements are acquired from ENC, and the elevation element is acquired from SRTM v4.1 digital elevation chart database developed by NASA. Then, the bathymetric and elevation terrains are generated, and the satellite images are superposed by using this terrain information. The longitudinal and latitudinal information of the AtoNs are converted to the 3-axis information to position the AtoN locations. The 3D objects such as bridges, buildings and port facilities are generated and the terrain visualization is completed. The proposed method realizes more realistic 3D terrain visualization of Busan Port.

• The Plant Pathology Journal
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• v.30 no.1
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• pp.51-57
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• 2014

A large-scale oligonucleotide (LSON) chip was developed for the detection of the plant viruses with known genetic information. The LSON chip contains two sets of 3,978 probes for 538 species of targets including plant viruses, satellite RNAs and viroids. A hundred forty thousand probes, consisting of isolate-, species- and genus-specific probes respectively, are designed from 20,000 of independent nucleotide sequence of plant viruses. Based on the economic importance, the amount of genome information, and the number of strains and/or isolates, one to fifty-one probes for each target virus are selected and spotted on the chip. The standard and field samples for the analysis of the LSON chip have been prepared and tested by RT-PCR. The probe's specific and/or nonspecific reaction patterns by LSON chip allow us to diagnose the unidentified viruses. Thus, the LSON chip in this study could be highly useful for the detection of unexpected plant viruses, the monitoring of emerging viruses and the fluctuation of the population of major viruses in each plant.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.11
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• pp.19-29
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• 2001

The Pan-European Digital Audio Broadcasting(DAH) system's performance is characterized and improved with the aid of turbo codec. From the fact that the first bit among the four coded bits at the RCPC coding defined in the Eureka 147 DAD system is not. punctured and always transmitted, this paper proposes a new turbo coded DAB system model that replaces the existing RCPC codec by a turbo codec without modifying the puncturing procedure and puncturing vectors defined in the standard DAB system for compatibility. The performance of a new system is compared to that of the conventional system under the Rician fading channel and the Rayleigh fading channel in conjunction with DAD transmission mode I and III suitable for the terrestrial single frequency network and satellite broadcasting.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.1
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• pp.79-90
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• 2016

The study has purposed in evaluating experiences for achievable accuracy and precision of time series at 3-D coordinates. It has been estimated from the kinematic medium-range baseline processing of Continuously Operating Reference Stations (CORS) for the potential application of crustal displacement analysis during an earthquake event. To derive the absolute coordinates of local CORS, it is highly recommended to include some of oversea country references, since it should be compromised of an observation network of the medium-range baselines within the length range from tens of kilometers to about 1,000 kilometers. A data processing procedure has reflected the dynamics of target stations as the parameter estimation stages, which have been applied to a series of experimental analysis in this research at the end. From the analysis of results, we could be concluded in that the subcentimeters-level of positioning accuracy and precision can be achievable. Furthermore, the paper summarizes impacts of satellite ephemeris, data lengths and levels of initial coordinate constraint into the positioning performance.