• Title/Summary/Keyword: time to first fix

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TTFF 감소를 위한 GPS 코드 기반의 개략 위치 추정 기법 설계

  • Yu, Won-Jae;Choe, Gwang-Ho;So, Hyeong-Min;Lee, Hyeong-Geun
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2016.05a
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    • pp.22-25
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    • 2016
  • 해상에서의 선박 항해에 있어서 GPS와 같은 위성항법시스템에 대한 의존도가 매우 높다. 하지만 전파 교란 등과 같은 열악한 환경이 선박 주위에 가해질 경우 선박에 탑재된 GPS 수신기에서 위치를 추정할 수 없기 때문에 정상적인 항해가 어렵게 된다. 본 논문에서는 위와 같은 약한 전파 교란 환경을 가정하여 열악한 환경 내에서 GPS 수신기가 위치 추정 정확도는 열화되더라도 자신의 위치를 처음 파악하는 데 걸리는 시간인 TTFF(Time To First Fix)를 감소시켜 선박의 신속한 위치 계산을 위한 개략 위치 추정 기법을 설계하였다. 또한 열악한 신호 환경을 가정하여 진행된 실험에서 기존 GPS TTFF와의 비교를 통해 설계된 기법을 검증하였다.

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A Study on the Property of Visual Perception of Interior Space - By revising the observation time of the design element - (실내공간의 주시특성에 관한 연구 - 전회공간의 주시시간 보정을 통해 -)

  • Choi, Gae-Young;Kim, Jong-Ha;Lee, Jeong-Ho
    • Korean Institute of Interior Design Journal
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    • v.18 no.5
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    • pp.128-136
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    • 2009
  • This study analyzed and defines the property of visual perception throughout the revision of the observation time of the original space and the rotating space. The conclusions of this study are as fellows: First, based on the existing theory and experiment, the study obtained the basis which decides the sector data originating fixation-gaze after staring the specific sector over 300ms time. It will become the turning point hereafter for our research to fix the time in this way. Second, in analyzing the minute data, the study built a revision method of the observation time by analyzing the meanings and the reasons of the revision of the original data. Third, according to the difference of revision quantity, female testee have more increases in the amount of data than male testee from the original screen. On the other hand, the opposite tendency appears from the previous data. This shows there is a difference in the observation properly by sex. Last, we could grasp Information about the property of the observation time throughout eyeball fixations, and the revision and analysis of the 'controlled observation data'. These data can be used in design element arrangement of interior space, hereafter.

The first record of Orthopsyllus species (Copepoda: Harpacticoida: Orthopsyllidae) from Korean waters

  • Park, Eun-Ok;Han, Mi Sun;Lee, Wonchoel
    • Journal of Species Research
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    • v.1 no.1
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    • pp.56-67
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    • 2012
  • During a study of harpacticoid copepods from Korea, one species of the family Orthopsyllidae was found by rinsing macroalgae collected from the intertidal and subtidal zones at Hangaechang, Munseum Islet in Jeju Island of Korea. The Orthopsyllus is closely related to Orthopsyllus linearis curvaspinata Mielke, 1993, however it is distinguished from the original description by the combined characters of slightly slender caudal seta V in the female, relatively short and ovoid caudal ramus, the seta formula of P3, and the length of P2 and P4 endopod in the male. Since Orthopsyllus linearis (Claus, 1866) is notorious for its incomplete previous descriptions and therefore its polymorphic status, it is premature to fix the status of present Orthopsyllus species from Korea, without the detailed comparative study among the congeners. However due to the urgent need for the report of the genus in the region, we report this species as Orthopsyllus linearis (Claus, 1866) like but different one within the genus: Orthopsyllus cf. linearis (Claus,1866). This is the first report of the genus Orthopsyllus for the first time in Korea.

User Demand on the Crematorium Facilities (화장장 이용자의 시설요구에 관한 연구)

  • 민병욱;이행열;이재근
    • Journal of the Korean Institute of Landscape Architecture
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    • v.27 no.4
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    • pp.122-130
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    • 1999
  • The main purpose of this project is to improve the funeral and grave culture which has brought about many social problems, and to fix the crematory culture as the future funeral ceremony in our country. In this study, we first investigated the actual condition of cremation culture. Second, we survey three representative crematorium as an object of study and investigated similar sample buildings in Japan, we analyzed the problem of existing crematorium. Finally, we arranged the basics to approach the space program and design criteria of this project. 1. The entrance of vehicles has been commonly concentrated to the opening time of crematorium. therefore, Peak time has come out as circulation of cremation and waiting time is increasing, also it is difficult to manage the congestion normally. 2. The whole problem of crematorium is poor environment, inferior buildings, noise, unsatisfactory ventilation and privacy, insufficient convenience facilities. 3. The user demand on the crematorium facilities is a private family room for waiting area, a farewell room for family members in a direct line, an outdoor rest area, and the various service facilities, and so on. 4. For improvement of the funeral and grave culture, it is necessary that crematorium is not a hatred facilities, as the conversion of consciousness, and to new shape of charnel as it wore family tomb.

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The Impact of Minimum Wage Policy on Employment in Myanmar

  • KYAW, Min Thu;CHO, Yooncheong
    • The Journal of Industrial Distribution & Business
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    • v.12 no.3
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    • pp.31-41
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    • 2021
  • Purpose: The purpose of this paper is to analyze the impact of the minimum wage policy and the employment labor force in Myanmar by exploring firms' actions such as installing supplementary machines to substitute for labor resources and by addressing gender issues in employment. Research design, data, and methodology: This paper applies a fixed-effect estimation method by using the World Bank's enterprise panel data set surveyed in Myanmar. Results: Findings suggest that the minimum wage reduces both full-time and part-time employment, while the first minimum wage policy increases overall female employment. The adverse impacts are more pronounced for female employees of Joint Venture enterprises and enterprises located in the less-populated regions. Investment in capital such as equipment and machinery increase to substitute for labor after the minimum wage policy implementation; as a result, full-time employment slightly decreases. Conclusions: Appropriate measures concerning the minimum wage policy must be prepared by the government and institutions related to the labor union to serve the well-being of employees. Government of Myanmar should fix the minimum wage in a reasonable period based on the fiscal year for both employers and employees to prevent possible issues and losses resulting from the minimum wage being set.

A-GNSS Performance Test in Various Urban Environments by Using a Commercial Low Cost GNSS Receiver and Service

  • Han, Kahee;Lee, Jung-Hoon;Im, Ji-Ung;Won, Jong-Hoon
    • Journal of Positioning, Navigation, and Timing
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    • v.7 no.4
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    • pp.205-215
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    • 2018
  • The recent emergence of new Global Navigation Satellite Systems (GNSS) has resulted in a gradual improvement in the performance of positioning services. This paper verifies the degree of improvement in positioning performance of Assisted-GNSS (A-GNSS) receivers using assistance information compared to standalone-GNSS receivers that do not use assistance information in various urban environments in Korea. For this purpose, field tests are performed in various urban and indoor environments in Korea. The assistance information is provided by u-blox's AssistNow Online and low-cost commercial receivers are used for mobile station receivers. Through experiments, the Time to First Fix (TTFF), acquisition sensitivity, and position accuracy performance improvement are analyzed. The results of the experiments show that using assistance data improved the performance in all experiment locations, and, in particular, a significant performance improvement in terms of TTFF.

Buyers' Payment of Price by Letters of Credit under CISG (국제물품매매협약상 매수인의 신용장에 의한 대금지급)

  • Heo, Hai-Kwan
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.41
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    • pp.103-132
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    • 2009
  • In international sales of goods, the buyer must pay the price for the goods as required by the contract and CISG, The buyer's this obligation includes taking such steps and complying with such formalities as may be required under the contract, which includes providing the seller with relevant letter of credit through the issuing bank. Where the parties have not stipulated the time limit within which the credit should be opened, but there is an agreed date or period for shipment, the time limit for the L/C opening should be calculated back from the agreed date of shipment or the first date of shipment, while, in addition, the buyer should open the L/C sufficiently earlier than the shipment date in order for the seller to be able to know the L/C's opening before beginning to ship the goods. The L/C provided the buyer should conform to the contract of sale. Therefore, for example, when an unconfirmed L/C is provided violating the agreement or the L/C opened states that, under a FOB contract, a "freght prepaid" bill of lading shall be presented as a required document of the L/C, the buyer has failed to perform his obligation. If the buyer fails to perform his obligations to provide the letter of credit, the seller may require the buyer to perform that obligation; may fix an additional period of time of reasonable length for performance of the obligation; or, the seller may declare the contract avoided, if the failure amounts to a fundamental breach of contract, or if the buyer does not, within the additional period of time fixed by the seller, perform the obligation; and the seller claim damages. However, when a relevant L/C has been issued for the seller, as a rule, he cannot ask directly for the buyer to pay the price before avail himself of the L/C first.

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Launch Environment Test for Scale magNetospheric and Ionospheric Plasma Experiment (SNIPE) Engineering Qualification Model (초소형위성 SNIPE(Scale Magnetospheric and Ionospheric Plasma Experiment) 시제인증모델의 발사환경시험 및 분석)

  • Kim, Min-Ki;Kim, Hae-Dong;Choi, Won-Sub;Kim, Jin-Hyung;Kim, KiDuck;Kim, Ji-Seok;Cho, Dong-Hyun
    • Journal of Space Technology and Applications
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    • v.1 no.3
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    • pp.319-336
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    • 2021
  • This paper discusses the results of launch environment tests for the engineering qualification model (EQM) of nanosatellite Scale magNetospheric and Ionospheric Plasma Experiment (SNIPE) for scientific missions and lessons learned for the design of nanosatellites. SNIPE is a group of four formation-flying 6U nanosatellites with a range of payloads for missions including space weather measurement. We developed the EQM to verify the preliminary design prior to fabricating the flight model. Launch environment test of EQM was conducted for the first time in 2019, and all failures were corrected and verified at the second test conducted in 2021. A notable point of the two tests is that the nanosatellite deployer used in the first test is different from that of the second test. The second deployer has the capability to fix the internal satellite whereas the first deployer just contains and deploys the satellite. Thus actual mechanical loads the satellite receives is reduced for the second test compared to the first test. This work compares the mechanical responses of two tests and proposes general guidelines for structural design of nanosatellites.

High School Students' Conceptions on Landscape Formation and Geological Time (고등학생들의 지형 형성과 지질학적 시간 개념)

  • Lee, Yongkyu;Han, Shin;Jeong, Jinwoo;Park, Taeyoon
    • Journal of the Korean Society of Earth Science Education
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    • v.8 no.3
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    • pp.332-345
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    • 2015
  • Earth science is the study to explore the planet in which we live. Among these earth science geology of the area it can be the most critical and important study. However, because of the size and scope is too broad temporal spatial eurona covered in geology is true that many students find difficult about the geology field. In this study, in conjunction with landscape formation of geologic time for the concept to be among the core areas of Geology examined the concept and recognize it as the destination for high school students. Is a test tool for the analysis was adapted for use by Jolley (2010) has developed LIFT (The Landscape Identification and Formation Test). Currently we fix the strip to match the country through a validity check of the curriculum. Results of the study were as follows: First, the ability to check the landscape and formation is expected to estimate the time and the liberal arts students was higher than the natural science students. The reason for this seems to be the influence of learning geographical subjects. Second, the concept of geological time was found to lack both natural science and liberal arts students. The reason is that the students in the previous process because it deals with the concept of geologic time from the top of Earth Science Education II seems to be because there was no chance of learning about geological time. Third, the results confirm the confidence of the students surveyed in the landscape formation time natural science students was higher than liberal arts students. The research measured gender boys higher than girls. Fourth, the students on the landscape and geological time was found to have a number of misconceptions. This appears to be due to the students to feel difficulty in thinking of the concept because the need to understand the abstract geologic time. Therefore, it is necessary just to hold misconceptions about the concept of geology students have through the study of the landscape and geological time.

KASS Message Scheduler Design

  • Yun, Youngsun;Lee, Eunsung;Heo, Moon-Beom;Nam, Gi-Wook
    • Journal of Positioning, Navigation, and Timing
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    • v.5 no.4
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    • pp.193-202
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    • 2016
  • The Korea Augmentation Satellite System (KASS), which is under development in Korea as a Satellite Based Augmentation System (SBAS) is expected to broadcast SBAS messages to air space in Korea according to the international standards defined by the International Civil Aviation Organization (ICAO) and the Radio Technical Commission for Aeronautics (RTCA). Around 13 SBAS messages are broadcast in every second to transmit augmentation information which can be applicable to a wide area in common. Each of the messages requires a different update interval and time-out according to the characteristics, purpose, and importance of transmitted information, and users should receive and combine multiple SBAS messages to calculate SBAS augmented information. Thus, a time to take acquiring first SBAS position by users differs depending on broadcasting various SBAS messages with which order and intervals. The present paper analyzes the considerations on message scheduling for broadcasting of KASS augmentation information and proposes a design of KASS message scheduler using the considerations. Compared to existing SBAS systems, which have a wide range of service area, a service area of the KASS is limited to Korea only. Thus, the numbers of ionosphere grid points and satellites to be augmented are expected to be smaller than those of existing SBAS. By reflecting this characteristic to the proposed design, shortening of broadcast interval of KASS message is verified compared to existing SBAS and a measure to increase a speed of acquisition of user navigation solution is proposed utilizing remaining message slots. The simulation result according to the proposed measure showed that the maximum broadcast interval can be reduced by up to 20% compared to that of existing SBAS, and users can acquire KASS position solution faster than existing SBAS.