• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.12
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• pp.65-72
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• 2008

This paper proposes a new dual-loop digital PLL(DPLL) using seamless frequency tracking methods. The dual-loop construction, which is composed of the coarse and fine loop for fast locking time and a switching noise suppression, is used successive approximation register technique and TDC. The proposed DPLL in order to compensate the quality of jitter which follows long-term of input frequency is newly added cord conversion frequency tracking method. Also, this DPLL has VCO circuitry consisting of digitally controlled V-I converter and current-control oscillator (CCO) for robust jitter characteristics and wide lock range. The chip is fabricated with Dongbu HiTek $0.18-{\mu}m$ CMOS technology. Its operation range has the wide operation range of 0.4-2GHz and the area of $0.18mm^2$. It shows the peak-to-peak period jitter of 2 psec under no power noise and the power dissipation of 18mW at 2GHz through HSPICE simulation.

• Journal of the Korean Geographical Society
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• v.43 no.1
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• pp.87-103
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• 2008

The geographical name is an expression of human knowledge about living conditions and a basic tool for understanding about regional cultures and history as a result of spatiotemporal changes. This study aims to understand the historical and regional characteristics by analyzing the frequency and distribution of geographical names of 1:50,000 topographic map in the early 20th century and materializing on electronic cultural atlas. The result of this analysis is as follows. First, the aspect of distributed geographical names on the Korean Peninsula reflects a general trait of the country's natural and human environment included geographical features, population, arable land, the number of counties and villages, and functions of administration and military, etc. Second, through the frequency and weight of their names, the analysis shows not only the change of native names, but also the country's phase of the time by Japanese colonial policies such as exploitation of resources, the construction of railroads, and a desire to control of the border area with Manchuria. In addition, the study identified regional characteristics and differences in environmental perception and preferences, and naming basis and forms by the comparative analysis of each type of geographical names associated with village and ridge such as 'Chi' 'Ryung' 'Duk' 'Hang' 'Pyeong' 'Gok'. In particular, those characteristics were largely affected from environmental difference of each area.

• Journal of the Korean Institute of Rural Architecture
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• v.16 no.1
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• pp.119-127
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• 2014

This study suggests institutional and methodological approaches for preservation of South Korea's registered cultural properties of modern architecture. The suggested approaches are as follows. First, in order to improve the current registration and preservation system for cultural properties, we need to employ both structure-based classification and style-based classification. Registration criteria for modern architecture properties need to include more detailed classification in terms of their structure: brick structure, steel concrete structure and post lintel structure. In terms of construction style, the properties need to be further classified into the western style, the traditional style and the Korean-western eclectic style. In addition, protection of registered cultural properties need to be achieved through legislation of a protection system. Second, while the current system sets out six methods for preservation of registered cultural properties of modern architecture, more specific preservation methods types and plans need to be continuously introduced. In particular, as for the method of partial preservation, the method needs to be further classified based on the usage of the relevant structure so as to allow for more diverse options. First, the 'Preservation by Interior Alteration' needs to be added to the category, where the exterior is preserved as it is and the interior is preserved through alteration. Also needs to be added the preservation method where the interior space is preserved as it is and the exterior space is altered, in case the finishing materials of the exterior has deteriorated. Third, if the records on registered cultural properties of modern architecture are to provide the functions of legal evidences regarding management of architectural cultural properties, sources of knowledge required for policy making and implementation and past management record for the future, each phase needs to be closely connected in an organic manner, and we need to establish a management system and plan that go beyond the relevant organizations. Fourth, in order to preserve South Korea's registered cultural properties of modern architecture in its original state, it is imperative to prepare separate criteria for registration of technicians with expertise on modern architecture, and train experts and technicians on modern architecture, which is distinguished from the traditional architecture.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.3
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• pp.27-37
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• 1997

The paper deals with the effectiveness of various special rudders on course stability of a ship. We adopted five types of rudder, such as one normal rudder and four special rudders, which contain two rudders with concave and convex strips on sides respectively, one flapped rudder, and one rudder with end plates on tips. In the circulating water channel, model test was carried out for measuring lift characteristics of the rudders in open water. And various captive model tests were also carried out for measuring the experimental constants related with helm angle and steering in hull-propeller-rudder system. From the test results, the changes in manoeuvring hydrodynamic derivatives due to adoption of normal and special rudders were predicted. Then course stability performances of a ship with normal and special rudders were evaluated and discussed. As a result, it is clarified that the rudder with concave or convex strips and flapped rudder have no effect on course stability, while the rudder with end plates improves course stability with effect. The result in this study is expected to be used usefully when the course stability is in issue and has to be improved without amendment of hull design at initial design phase or after construction of a ship.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5534-5540
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• 2015

This In the railway signaling system, applications of axle counter in addition to track circuit goes on increasing for detecting train position. Consequently, this paper compares sensor methods of axle counter with between geo-magnetism method and proximity sensor method. And it presents differences and results, to improve reliabilities of train detection and axle counting. Also, this article presents an applied result which is based on field experience, with regard to installation, considering attachment condition of sensor part for accurate axle counting. This study acquires expandability that is able to perform not only axle counting function but also various other functions (direction detection of train, speed detection of train, and so on). It was a result of a change of design in order to judge phase difference of sensors, to improve reliability of axle counting. Furthermore, it does not subordinate to characteristics (type, weight of train). And it is confirmed that the omission of axle counting was not occurred in 350km/h. This was the result of Lab test after the construction of transfer equipment of trial axle and Test Bed for axle counting. Both of them are self-productions. Through this, it prepares foundation which is able to apply not only to train detection but also to speed of passing trains, formation number of trains, detector locking condition - when the train passes the section of switch point, and level crossing devices. Furthermore, it would be judged to contribute safety train operation if proximity sensor method applies to the whole railway signaling system from now on.

• Journal of Internet Computing and Services
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• v.19 no.4
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• pp.135-150
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• 2018

The biological resources research data around the world are not only very critical themselves but should be shared and utilized. Up to now, the biological resources have been compiled and managed individually depending on the purpose and characteristics of the study without any clear standard. So, in this study, the data reference model would be suggested which is applicable in the phase ranging from the start of the construction of the information system and which can be commonly used. For this purpose, the data model of the related information system would be expanded based on the domestic and foreign standards and data control policy so that the data reference model which can be commonly applicable to individual information system would be developed and its application procedure would be suggested. In addition, for the purpose of proving the excellence of the suggested data reference model, the quality level would be verified by applying the Korgstie's data model evaluation model and its level of data sharing with the domestic and foreign standards would be compared. The test results of this model showed that this model is better than the conventional data model in classifying the data into 4 levels of resources, target, activities and performances and that it has higher quality and sharing level of data in the data reference model which defines the derivation and relation of entity.

• Journal of Korea Water Resources Association
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• v.37 no.8
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• pp.653-662
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• 2004

In this study, the method of Increasing the flood control as well as conservation effects is studied by joint operation of Hwacheon and Peace Dam. After completing the second phase of the construction of the Peace Dam, the dam crest height will be increased from 225m and the storage capacity will also be increased. If storage capacity is increased and gates are installed, it will assist not only flood control but also conservation of the entire Han river basin. Considering the change of conservation levels, the change of the restricted water level of the Hwacheon Dam in flood season, and the inflow change into the Peace Dam through the simulated reservoir operation, the annual average power of Hwacheon Dam with 95% reliability, annual firm power, the volume of water supply is calculated. As a result, when the conservation level of the Peace Dam and the restricted water level of the Hwacheon Dam are increased, the generation capacity will be improved. However, even though the inflow decrease, the generation capacity will not be affected. If the inflow decrease under the same conditions, the water supply capability will be reduced to the range from 35% to 40%. It is necessary to increase conservation level to keep the same water supply capability.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.689-695
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• 2015

The offshore plant crews that were commissioned in the commercial startup phase boarded the offshore plant in two shifts until the end of the project. The crews who were hired by the owner side stayed in the original offshore plant during the project. However, most of the offshore plant commissioned members who were dispatched from the shipyard were accommodated in the offshore accommodation barge. For this reason, they were exposed to many accidents since there are a lot of people staying in a small space. This study suggested a method for improving survival rate at offshore accommodation barge in terms of life safety. It is assumed that the fire accident among unfortunate events which take place in the offshore accommodation barge mainly occurred. So, this study analyzed the safety evacuation for offshore plant employees using fire simulation model based on both domestic and international law criteria. In particular, When fire occurs in the offshore accommodation barge, the periodically well trained crews are followed safety evacuation procedure. whereas many employees who have different background such as various occupations, cultural differences, races and nationality can be commissioned with improper evacuation behaviors. As a result, the risk will be greater than normal situation due to these inappropriate behaviors. Therefore, This study analyzed the Required Safe Escape Time (RSET) and Available Safe Escape Time (ASET). Also it was suggested the improvement of structure design and additional arrangement of safety equipment to improve the survival rate of the residents in offshore accommodation barge.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.2
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• pp.205-213
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• 2010

This study was to analyze the past regime's real estate policy and the time-series data on real estate price index from 1986 to 2009 in 24 years. Also, the real estate index and macroeconomic variables, the impact on house price index variable conducted to regression analysis and to analyze whether and how much is affected. Analyzed as follows: First, Korea's real estate policy was the post-policy and the past regime's real estate policy was inconsistent with each other. Second, in the normal phase whenever real estate issues, the measures of the strengthening regulation and of the economic recovery were only to repeat periodically. Third, the timing and means of policy enforcement was an inappropriate and Real estate market was getting worse at the time whenever a real estate policies performed. Fourth, The apartments prices index of the housing types rose the highest and were the most popular for 24 years. Increase or decrease the amount of the price index for apartments, Roh Tae-woo(65.0%) - Kim Dae-jung (42.5%) - Roh Moo-hyun (32.8%) were in order. Fifth, the results of the regression analysis carried out: The impact on housing prices among independent variables were followed by Cap Construction- one per capita income - Housing consumer price index - Accompanying Composite Index - Trailing Composite Index - Home subscription Subscriber account - Leading Composite Index.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.3
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• pp.193-202
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• 2013

The concentrations of heavy metals such as cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), zinc (Zn), nickel (Ni), and arsenic (As) in sand samples collected from selected children's playground and their correlation with environmental parameters, such as concentration of particulate matter in the atmosphere ($PM_{10}$), apartment age (> 5 years), clay and organic matter contents in sand samples, were analyzed. The average heavy metal concentration in samples was 0.040 mg $kg^{-1}$ for Cd, 0.200 mg $kg^{-1}$ for Cr, 1.75 mg $kg^{-1}$ for Cu, 15.1 mg $kg^{-1}$ for Ni, 3.42 mg $kg^{-1}$ for Pb, 66.7 mg $kg^{-1}$ for Zn and 0.750 mg $kg^{-1}$ for As, all of which were below the environmental regulatory level established by Korea Ministry of Environment. However, in the consideration of direct and oral exposure by children to playground sand, the risk of the concentration range in the samples might be greatly enhanced. Heavy metal concentration in samples collected from high $PM_{10}$ (> $70{\mu}gm^{-3}$) area was slightly greater than in samples from low $PM_{10}$ (< $70{\mu}gm^{-3}$), indicating the contribution of particulate matter in air phase to heavy metal concentration in playground sand samples. The concentrations of both Cd and Pb were the highest in apartments older than 21 years (0.050 mg $kg^{-1}$ and 5.28 mg $kg^{-1}$ for Cd and Pb respectively) and showed positive correlation with apartment age (p<0.01 and p<0.001 for Cd and Pb, respectively). Clay content in playground sands ranged 3.8~11.2% and was positively correlated with heavy metal concentration. Organic matter content was negligible (mostly < 0.1%) and showed poor correlation with heavy metal concentration. In conclusion, concentration of heavy metals in playground sand was found to be predominantly influenced by the apartment age and clay content in sand samples and supplemented by dust deposition of particulate matter ($PM_{10}$) from atmosphere.