• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.8
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• pp.761-766
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• 2008

This paper analyzes the availability and Dilution Of Precision (DOP) of GPS, widely used in positioning, with and without augmentation using QZSS (Quasi-Zenith Satellite System). Orbit simulator for QZSS is developed using Kepler‘s orbital parameters. Also 3D modeling technique based on three-Dimensional GIS digital map and satellite tracking algorithm for visible satellite simulation system are discussed. Performance improvement of the availability and DOP were achieved by combining GPS with QZSS at urban environment of Seoul.

• The KIPS Transactions:PartA
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• v.18A no.4
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• pp.143-150
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• 2011

This paper presents an EDF based scheduling algorithm for scheduling imprecise computation model where each task consists of mandatory part and optional part. Imprecise computation is useful to manage overload condition. In overload situation, some optional parts should be removed. The proposed DOP algorithm removes optional parts of earlier deadline tasks to enhance flexibly for newly arriving tasks. A simulation result shows that DOP has better performance than other algorithms.

• Resources Recycling
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• v.11 no.2
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• pp.14-19
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• 2002

PVC sheet was treated in O~10M NaOH solutions at $80~150^{\circ}C$ for O~7 hour, in order to study the leaching phenomena of plasticizer. The yield of phthalic acid produced by hydrolysis of DOP was increased greatly with increasing temperature and NaOH concentration by accelerating of alkali catalyst. The yield of phthalic acid was reached ca. 100% in 10M NaOH at $150^{\circ}C$ over 3 hours. Therefore, the plasticizer containing 30% in PVC sheet could be hydrolyzed in alkali solutions before the occurrence of dehydrochlorination. Besides, in the thermal reaction, the pores were produced in the PVCsheet by the hydrolysis of DOP.

• Nuclear Engineering and Technology
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• v.16 no.1
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• pp.29-35
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• 1984

Filtration efficiency tests were conducted on a fiberglass mat filter with DOP aerosol having a diameter from 0.l${\mu}{\textrm}{m}$ to 0.45${\mu}{\textrm}{m}$ in the face velocity range of 1cm/sec to 10cm/sec. Filtration of submicron particles by a fibrous filter is characterized by a face velocity. The size of DOP aerosol which has a minimum removal efficiency decreases with increasing the velocity. A numerical solution of the diffusion equation is obtained for a fiberglass mat filter by using "Kuwabara's cell model" for the flow field and Von Mises Transformation for the actual flow around a fiberglass. The present theoretical results agree quite well with the experimentals for fiberglass mat. This result could be contributed to predict the removal efficiency on an air filter and to optimize the operating condition of an air purification system with a filter. a filter.

• Journal of Advanced Navigation Technology
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• v.16 no.6
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• pp.944-951
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• 2012

The conventional indexes for describing the GNSS positioning performance such as satellite visibility, dilution of precision (DOP) and signal to noise ratio is very useful in open sky, however, they are not useful in the land road environment. In this paper new index is suggested for describing the GNSS positioning performance for the road environment. The new index is called Sky View based DOP (SVDOP). SVDOP is derived referring the Sky-View-Factor (SVF). The usefulness is analyzed by comparing the SVDOP and SVF in land road environment after the singularity points are selected and SVDOP is calculated.

• Ocean and Polar Research
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• v.39 no.1
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• pp.35-43
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• 2017

Concentrations of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), dissolved organic phosphate (DOP), and colored dissolved organic matter (CDOM) were measured in the coastal sea off inland aqua farms in northeastern Jeju Island in summer 2015. The highest concentrations of DOC, DON, and DOP were revealed in the surface water off Hado-ri where the lowest salinity conditions prevailed (31.6). The concentrations of DOC, DON, and DOP in the surface water were lower in the inner stations (SH1-1, 1-2, and 1-3) near the aqua farms of the Haengwon-ri than in the outer stations. The concentrations of DOC, DON, and DOP negatively correlated with salinity. These results indicate that the contribution of dissolved organic matter (DOM) from the aqua farms seems to be not significant. On the other hand, the higher concentrations of DON and DOP in the inner stations of Hado-ri (HD 1-1) seem to be attributed to excrement of migrating birds. The three components of CDOM (T, M, and C peaks) showed no relationship with salinity, perhaps due to various in situ productions by marine organisms and decomposition by ultraviolet radiation. The observed lower C:M ratio, an indicator of terrestrial source, and the higher biological index (BIX) of CDOM in the station off Hado-ri indicate that DOM is produced mainly by biological activity. Based on the higher humification index (HIX) of CDOM and the higher DOC:DON ratio off Haengwon-ri, refractory DOM in the inland aqua farms is likely transported to the coastal sea.

• ALGAE
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• v.18 no.4
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• pp.281-288
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• 2003

To study the environmental features causing a bloom of the novel dinoflagellate Heterocapsa circularisquama (Dinophyceae), hydrographic and chemical aspects were measured in the Uranouchi Bay, Kochi Prefecture, Japan, from January to December, 1997. The cell density of H. circularisquama increased rapidly in early October, and dropped sharply in mid-October. Growth rate of H, circularisquama during bloom period appeared 1.50 division day$^{-1}$ under high water temperature (25$^{\circ}C$) and salinity (32 psu) conditions. Althought the result from hydrographic aspect indicated good condition for their growth, dissolved inorganic phosphorus (DIP) concentration in surface layer before bloom formation was less than 0.70uM, which is lower than their half saturation constant(Ks). Dissolved inorganic nitrogen(DIN): DIP ratio was > 30, indicating potential P-limitation. However, before bloom formation period of H. circularisquama, DIP concentrations were high in bottom layer (> 4.0 uM). Some studies reported that H. circularisquama had the ability to migrate vertically and to utilize dissolved organic phosphorus (DOP). Thus, DIP in bottom layer might have been utilized by H. circularisquama for their growth.DOP might have weakly affected their growth because of low reactive DOP concentrations owing to low DOP concentration (ca. 0.39 uM). Thus, if nutrient condition of bottom layer in Uranuchi Bay is not improved, the outbreaks of H. circularisquama red tides may became an annual feature.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.9
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• pp.1069-1080
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• 2016

TDOA(Time Difference Of Arrival)-based localization system such as the passive surveillance system performs the time synchronization between the receivers after separated installing multiple receivers to set the same clock for all receivers. And it estimates 2D(or 3D) location of the target by solving intersection of the multiple hyperbola(or hyperboloid) using TDOA. To perform time synchronization, one receiver must be set to the master, and it provide the reference data to compensate the clock of the rest of the slaves. The positioning accuracy of TDOA-based localization system is changed in accordance with the master that is selected among multiple receivers. So, the optimum receiver which is selected among multiple receivers must be set to master to get best performance in the considered deployment of receivers. In this paper, we propose a selection scheme of master receiver for time synchronization using DOP(Dilution Of Precision) which is based on location of the target and the multiple receivers. The proposed scheme has low complexity and short processing time, and it is easy to automate in the TDOA-based localization systems.

• Journal of Korean Society on Water Environment
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• v.24 no.3
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• pp.354-364
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• 2008

The variability in the phosphorus concentrations and the decomposition rates of organic phosphorus were measured in two rivers, the Youngsan River and the Sumjin River through four surveys in June, August and December of 2006 and February of 2007. Water samples were incubated for 20 days in a dark incubator and the change of forms of phosphorus (POP, DOP, DIP) were analyzed. By fitting the change to four types of models the decomposition rates of organic phosphorus were determined. The mean total organic phosphorus (TOP) decomposition rate coefficients in the Youngsan River and the Sumjin River were $0.036day^{-1}$ and $0.035day^{-1}$, respectively. In POP$\rightarrow$DIP model, the average decomposition rate coefficients in the Youngsan River and the Sumjin River were 0.049 and $0.035day^{-1}$, respectively. The average POP decomposition rate coefficients of POP$\rightarrow$DOP$\rightarrow$DIP model were $0.042day^{-1}$ and $0.038day^{-1}$ in the Youngsan River and Sumjin River respectively while the mean DOP decomposition rate coefficients were $0.255day^{-1}$ and $0.244day^{-1}$, respectively. In the Youngsan River, the mean POP$\rightarrow$DOP decomposition rate coefficient and POP$\rightarrow$DIP decomposition rate coefficient of POP$\rightarrow$DOP$\rightarrow$DIP, POP$\rightarrow$DIP model were $0.039day^{-1}$ and $0.007day^{-1}$, respectively. And in the Sumjin River, the above decomposition rate coefficients were $0.031day^{-1}$ and $0.004day^{-1}$, respectively. The decomposition rate coefficients measured in this study might be applicable for modeling of river water quality.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.8
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• pp.1104-1110
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• 2014

This paper investigates geometric effect of landmarks on three-dimensional navigation error in landmark-based vision navigation systems. Dilution of precision is derived for landmark measurement error on the focal plane of the camera and separately expressed in position DOP and attitude DOP. Values of DOP are observed for various configurations of landmarks.