• Journal of The Korean Astronomical Society
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• v.37 no.4
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• pp.159-169
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• 2004

This is a proposal to probe local part of the interplanetary dust (IPD) cloud complex and retrieve mean volume emissivity of the local IPDs at mid-infrared wavelengths. This will be done by monitoring, with Infrared Camera (IRC) aboard the ASTRO-F, the annual modulation of the zodiacal emission. In pointing mode of the ASTRO-F mission the spacecraft can make attitude maneuvering over approximately ${\pm}1^{\circ}$ range centered at solar elongation $90^{\circ}$ in the ecliptic plane. The attitude maneuvering combined with high sensitivity of the IRC will provide us with a unique opportunity observationally to take derivatives of the zodiacal emission brightness with respect to the solar elongation. From the resulting differential of the brightness over the ${\pm}1^{\circ}$ range, one can directly determine the mean volume emissivity of the local IPDs with a sufficient accuracy to de-modulate the annual emissivity variations due to the Earth's elliptical motion and the dis-alignment of the maximum IPD density plane with respect to the ecliptic. The non-zero eccentricity ($e_{\oplus}$= 0.0167) of the Earth's orbit combined with the sensitive temperature dependence of the Planck function would bring modulations of amplitude at least $3.34\%$ to the zodiacal emission brightness at mid-infrared wavelengths, with which one may determine the IPD temperature T(r) and mean number density n(r) as functions of heliocentric distance r. This will in turn fix the power-law exponent $\delta$ in the relation $T(r) = T_o(r/r_o)^{-\delta}$ for the dust temperature and v in $n(r) = n_o(r/r_o)^-v$ for the density. We discuss how one may de-couple the notorious degeneracy of cross-section, density, reference temperature $T_o$ and exponent $\delta$.

• The Journal of the Korea Contents Association
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• v.20 no.3
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• pp.635-644
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• 2020

This paper examines the types and functions of politeness in German communication and how politeness strategy can be realized. 'Politeness' is not a grammatical terminology in German, but it can be found in many places in grammar. The criteria for politeness are not only organized according to the rules of the language system, but the boundaries are ambiguous because non-language factors affect communication. Politeness is an important strategic element as well as social value. The polite expression first appears in the grammatical level of invariant with the form of address according to the familiarity between the conversational parties, verb modus, and modal particle. Modal particle with familiarity is considered to be a positive politeness strategy that limits the listener's speech by weakening or avoiding face threatening act. Modal verbs is classified as polite expressions that do not impose a psychological burden by not forcing the listener to make a direct request. The results of this study are therefore expected to suggest a rationale for empirical research on politeness in German communication.

• Safety and Health at Work
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• v.3 no.4
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• pp.278-286
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• 2012

Objectives: Authors investigated the pattern of the rate of occupational injuries and illnesses (ROII) at the level of enterprises in order to build a network for exchange of experience and knowledge, which would contribute to workers' safety and health through safety climate of workplace. Methods: Occupational accidents were analyzed at the manufacturing work site unit. A two step clustering process for the past patterns regarding the ROII from 2001 to 2009 was investigated. The ROII patterns were categorized based on regression analysis and the patterns were further divided according to the subtle changes with Mahalanobis distance and Ward's linkage. Results: The first clustering of ROII through regression analysis showed 5 different functions; 29 work sites of the linear function, 50 sites of the quadratic function, 95 sites of the logarithm function, 62 sites of the exponential function, and 54 sites of the sine function. Fourteen clusters were created in the second clustering. There were 3 clusters in each function categorized in the first clustering except for sine function. Each cluster consisted of the work sites with similar ROII patterns, which had unique characteristics. Conclusion: The five different patterns of ROII suggest that tailored management activities should be applied to every work site. Based on these differences, the authors selected exemplary work sites and built a network to help the work sites to share information on safety climate and accident prevention measures. The causes of different patterns of ROII, building network and evaluation of this management model should be evaluated as future researches.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.2
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• pp.188-198
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• 2013

In constructing a collision avoidance system, it is important to determine the time for starting collision avoidance maneuver. Many researchers have attempted to formulate various indices by applying a range of techniques. Among these indices, collision risk obtained by combining Distance to the Closest Point of Approach (DCPA) and Time to the Closest Point of Approach (TCPA) information with fuzzy theory is mostly used. However, the collision risk has a limit, in that membership functions of DCPA and TCPA are empirically determined. In addition, the collision risk is not able to consider several critical collision conditions where the target ship fails to take appropriate actions. It is therefore necessary to design a new concept based on logical approaches. In this paper, a collision ratio is proposed, which is the expected ratio of unavoidable paths to total paths under suitably characterized operation conditions. Total paths are determined by considering categories such as action space and methodology of avoidance. The International Regulations for Preventing Collisions at Sea (1972) and collision avoidance rules (2001) are considered to solve the slower ship's dilemma. Different methods which are based on a constant speed model and simulated speed model are used to calculate the relative positions between own ship and target ship. In the simulated speed model, fuzzy control is applied to determination of command rudder angle. At various encounter situations, the time histories of the collision ratio based on the simulated speed model are compared with those based on the constant speed model.

• Journal of Digital Convergence
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• v.15 no.1
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• pp.247-253
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• 2017

Feature selection or variable selection is a data mining scheme for selecting highly relevant features with target concept from high dimensional data. It decreases dimensionality of data, and makes it easy to analyze clusters or classification. A feature selection scheme requires an evaluation function. Most of current evaluation functions are based on statistics or information theory, and they can evaluate only for single feature (one-dimensional data). However, features have interactions between them, and require evaluation function for multi-dimensional data for efficient feature selection. In this study, we propose modification of FSDD evaluation function for utilizing evaluation of multiple features using extended distance function. Original FSDD is just possible for single feature evaluation. Proposed approach may be expected to be applied on other single feature evaluation method.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1395-1411
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• 2009

The Korea railroad industry has experienced the operating deficit annually since 1980. And the ridership has been reduced since 1990. Therefore, a structural reform of the Korea railroad industry conducted at 2003. Basic principles of their structural reform are no differences among the Korea and advanced counties. But different outcomes depending on each country situation appears. These cost functions appear the existence of all economic of scale. And when increase the average transport distance annually, the average cost reduce annually. The results of structural reform by comparing before and after, the average cost was lower than previously. The Structural reform and the operation of the KTX, the two effects at the same time, the synergy effect has occurred. Because of the synergy effect, the performance is estimated to be larger. Due to the effective operation of structural reform that could reduce costs.

• Journal of Korean Society for Geospatial Information Science
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• v.3 no.2 s.6
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• pp.131-136
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• 1995

In this paper, We explain the development of helicopter avation information system which provides the current location and other pre-saved informations in order to guarantee the safe aviation. The system we developed has the functions such as displaying digital map data and current location, route planning, displaying the rate of deviation, calculating and displaying the cross sectional view through the route and providing a real-time speed, heading and other informations. In this system, we use GPS to get the current location, made the 1:250,000 digital map to display the current location and made the cross sectional view from the DEM(Digital Elevation Mode)) data to help safe aviation. This system provides many kinds of route setting methods by using UTM coordinates, Lati. Longi, coordinates, database of heliport location, scanned map, etc., and displaying the heading and distance. Moreover, it also has a characteristic of providing a consistent user interface.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.4
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• pp.201-209
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• 2007

Line transect sampling in a sighting survey is one of most widely used methods for assessing animal abundance. This study applied distance data, collected from three sighting surveys using line transects for finless porpoise that were conducted in 2004 and 2005 off the west coast of Korea, to four models (hazard-rate, uniform, half-normal and exponential) that can use a variety of detection functions, g (x). The hazard-rate model, a derived model for the detection function, should have a shoulder condition chosen using the AIC (Akaike Information Criterion), as the most suitable model. However, it did not describe a shoulder shape for the value of g(x) near the track tine and underestimated g (x), just as the exponential model did. The hazard-rate model showed a bias toward overestimating the densities of finless porpoises with a higher coefficient of variation (CV) than the other models did. The uniform model underestimated the densities of finless porpoise but had the lowest CV. The half-normal model described a detection function with a shape similar to that of the uniform model. The half-normal model was robust for finless porpoise data and should be able to avoid density underestimation. The estimated abundance of finless porpoise was 3,602 individuals (95% CI=1,251-10,371) inshore in 2005 and 33,045 individuals (95% CI=24,274-44,985) offshore in 2004.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.3
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• pp.138-144
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• 2018

Inventory inspection is an important task to eliminate the inconsistency between real assets and inventory management systems, and it is performed periodically at the site. In the case of a large-sized property, it is mainly managed in an outdoor workshop or a warehouse. However, due to the large area of the outdoor area, it is relatively difficult to identify the quantity and location of the property and is also vulnerable to theft. To solve this problem, we proposed a method and system for performing a warehouse inventory inspection using an unmanned aerial vehicle (UAV) and Bluetooth low energy (BLE) beacons. The proposed method has the following advantages. First of all, if we carry out inventory inspection by utilizing UAV, we can minimize user's effort compared to existing methods. The method of recognizing the asset by attaching the BLE beacon is more costly than using the existing RFID technology, but it is advantageous because the recognition distance is increased and the battery life of the tag is drastically increased. We also designed a BLE beacon reader for the system and implemented a prototype to show the feasibility of the proposed system. The prototype is based on Genuino 101, which is a kind of arduino, and adds HM-10 and Neo-6m modules to provide Bluetooth and GPS functions. The BLE beacon reader was tested in outdoor, and attached in drone. We also developed an inventory checking system based on the web to display results of inventory checking. The proposed approach enables the users to automate the operation of inventory checking on an outdoor warehouse.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.10
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• pp.40-50
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• 1999

The novel network architecture is recently required to accommodate a variety and intelligence of communication services. It is also required to provide customized network functions and to efficiently satisfy a various user's requirements. Accordingly, open network architecture based on ATM transport network features has been mainly studied in communication network. This paper evaluates the VSN(Virtual Switch Network) characteristics in the call processing of IMT-2000 switching system, which is composed of VSN instead of ATM switch network. VSN means switch network which is composed of ATM transport network. As a result, this paper proposes new VSN based ATM-MSC architecture with integrated call and connection control systems. and evaluates call processing delay characteristics using call process procedures. Internal call processing delay is increased approximately 3.5msec than the conventional ATM switching system. The experimental values applied in the analysis condition are the load 0.8, and the 100km distance between CCCPs(Call and Connection Control Processors) and VSNs. It is confirmed that the VSN has the potentiality in the practical implementation.