• Fire Science and Engineering
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• v.27 no.5
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• pp.8-14
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• 2013

In the subway, various fires continue to take place across the world. In the Daegu subway accident in 2003, many people were damaged by shortened visibility range caused by toxic gas and smoke. This paper, assuming that a subway fire happens in the Mandeok Station of the subway system in Busan, analyzed different smoke-spreading situations depending on the ventilation situation at its platform (opening of the train doors, operation of ventilation facilities in the tunnel, and working of fire door), using FDS. The calculation proved that it would be more effective to secure evacuation route when the ventilation facilities of the tunnel are not operated, than when they are on. And, it was also found that the case where the doors of the platform to the escape route and only the platform-facing doors of the subway car on fire office are open would be more effective to ventilation than the case where all the doors are open. And, it was found to be important that the fire doors of the platform are working properly.

• Journal of KIISE
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• v.43 no.8
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• pp.848-856
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• 2016

Seeking and recognizing maritime targets are very important tasks for maritime safety. While searching for maritime targets using radar is possible, recognition is conducted without automatic identification system, radio communicator or visibility. If this recognition is not feasible, radar operator must tediously recognize maritime targets using movement features on radar base on know-how and experience. In this paper, to support the radar operator's mission of continuous observation, we propose an algorithm for automatic recognition of an unknown ship using movement features on radar and a method of detecting potential ship related accidents. We extract features from contact range, course and speed of four types of vessels and evaluate the recognition accuracy using SVM and suggest a method of detecting potential ship related accidents through the algorithm. Experimentally, the resulting recognition accuracy is found to be more than 90% and presents the possibility of detecting potential ship related accidents through the algorithm using information of MV Sewol. This method is an effective way to support operator's know-how and experience in various circumstances and assist in detecting potential ship related accidents.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.3
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• pp.260-267
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• 2007

GPS adapter kit (GAK) is a GPS/INS guided range extension system to improve the accuracy and availability of existing dumb bombs. In this paper, a van test result of GPS/INS navigation module (NM) for guided bomb with GAK has been presented. The NM consists of a commercial MEMS IMU, embedded GPS receiver and navigation computer unit (NCU). The GPS receiver of NM was designed to use multiple antennas for satellite visibility and GPS attitude determination. The real-time navigation software was designed by modularized structure to guarantee the maintainability and extensibility. In order to evaluate the performance of the NM, a van test was preformed by using a high performance INS - Honeywell H-726 MAPS(Modular Azimuth Position System).The van test results show that the GAK NM with GPS attitude measurement gives better navigation performance than a conventional GPS/INS integration and good coasting capabilities under jamming environment.

• YAKHAK HOEJI
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• v.53 no.6
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• pp.328-333
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• 2009

Contrast media are substances that are used to enhance the contrast of structures or fluids within the body in medical imaging. Those are commonly used to enhance the visibility of blood vessels and the gastrointestinal tract. The aim of this study is to evaluate patients who got injected iopamidol, developed as one of contrast medium regarding changes in cardiovascular system and especially, adverse drug reactions. This study were performed on randomly selected a total of 51 patients (range of 15~85 years old) who got injected contrast medium, Iopamidol at a P hospital in Gyeonggi province from September 22nd, 2008 to January 24th, 2009. Data were collected by questionnaire though person to person. We analyzed the data by SPSS (Version 12. for windows). Methods of analysis were frequency and cross analysis. In results, 19.6% (n=10) were founded for adverse drug reactions of contrast medium. 25.0% (n=4) of 10 patients who had adverse drug reactions of contrast medium had took abdomen contrast test. 2 patients of those took contrast test for chest. Also, 3.9% (n=2) patients felt vomiting and nausea after injection of contrast medium. In conclusion, 19.6% patients experienced adverse drug reaction of contrast medium. Therefore, when taking radiation test, we should make efforts to minimize adverse drug reactions to achieve suitable and effective treatment.

• Current Optics and Photonics
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• v.1 no.4
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• pp.351-357
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• 2017

This paper proposes a LED bicycle headlamp with a wide viewing angle to help bicyclists see the front effectively and because of its high visibility to reduce the risks of accidents around intersections or blind spots. The wide viewing angle was determined to be $28^{\circ}$ because it can illuminate a 5 m wide area 10 m away. Therefore, the road conditions of the intersection can be observed with the bicycle handlebar tilted slightly to the left or right. The headlamp has a compact reflector with a width of 30 mm, height of 27 mm, and length of 17 mm. Owing to its size, a change in the position of a light source leads to severe changes in light distribution. Therefore, the tolerance of the source position was analyzed by a simulation. The tolerance was ${\pm}0.5mm$ at the X, Y and Z axes within a less centered aiming range of ${\pm}1^{\circ}$. Finally, the prototype of the bicycle headlamp was made and the light distribution was measured by an automotive headlamp light measurement system. The experimental results indicate that the headlamp illuminates a 5 m wide area with an edge light of 3.2 lx as well as meeting the K-mark regulation.

• Aerospace Engineering and Technology
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• v.1 no.1
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• pp.173-176
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• 2002

This report summarizes the results of MODTRAN model that are used for the calculation of input radiance of the KOMPSAT-2 Multispectral Camera (MSC). We have calculated the input radiances for four months: January 15, April 15, July 15 and October 15. Annual averages are the arithmetic mean of results from four months. We used the mid-latitude winter and summer for the month of January and July, respectively, while US standard atmospheres are used for April and October. The orbital characteristics of KOMPSAT-2 and the seasonal variations of solar zenith angle over the Korean peninsula were incorporated as inputs to the model. The tropospheric aerosol extinction (visibility = 50 km) was assumed. The surface albedo used in the model calculation represents the global annual mean clear-sky albedo. MSC contract values are found to be considerably greater in the MSC spectral range than the total radiances calculated with the above general conditions. From these results, it can be inferred that the forthcoming MSC images would be somewhat dark. We certainly need a countermeasure for this issue.

• Journal of the Korean Institute of Rural Architecture
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• v.21 no.2
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• pp.11-18
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• 2019

This study aims to identify the actual condition of local food stores that serve as a regional activation space within the highway rest area. It analyzes and examines user awareness, and presents desirable directions for the establishment of new local food stores and improvement of existing facilities. The research method was conducted as follows: the status of 226 rest areas were examined which were installed on national highways, location conditions and convenience facilities. Second, a physical survey was conducted on 116 local food stores(floor area, location) and a user awareness survey on 63 local food stores. The results of the analysis and review have been concluded as follows. First, it is necessary to consider the establishment of a local food store in order to promote the local community by using various cultural and environmental conditions in the highway rest area, and to secure a public space to promote exchanges with local residents and revitalize the local economy. Second, considering the continuous increase of highway users, location, and traffic conditions, diversification of convenience functions including local food stores should be considered even if it is a medium and small highway rest area. Third, the floor area of local food stores is generally planned within a range of $75m^2$ to $125m^2$, and its location should be integrated with the rest area as much as possible. Inevitably, when you need to construct separately at the exit or entrance, you need to consider a unique design that ensures accessibility and visibility.

• Safety and Health at Work
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• v.11 no.4
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• pp.537-542
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• 2020

Background: Personal protective equipment (PPE) has been designed in such a way to reduce accident rates. Unfortunately, existing PPE is rather ineffective as it is not able to provide warning signals when hazard is around. The integration of intelligent systems is envisaged to increase the efficiency of existing PPE. Methods: This project designed a safety vest incorporated with metal detectors which can provide immediate warning to the field workers when there is metal hazard around. This product has greater freedom of design via smart manufacturing as it involves the assembly of few commercially available parts into a single entity. Briefly, the metal detector is a do it yourself (DIY) kit, and the safety vest is purchasable from any local market. The DIY kit was connected to a copper coil and being sewed into the safety vest. Results: The metal detector induces beeping sound when there is metal hazard around. A total of 121 engineering students were introduced to the prototype before being requested to answer a survey associated with the design. Respondents have rated >3.00/5.00 for the design simplicity, ease of usage, and light weight. Meanwhile, respondents suggested that the design should be further improved by increasing the metal detection range. Conclusion: It is envisaged that the introduction of this smart safety vest will allow the workers to carry out their duties securely by reducing the accident rates. Particularly, such design is expected to reduce workplace accident especially during night time at construction sites where the visibility is low.

• International Journal of Computer Science & Network Security
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• v.23 no.1
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• pp.153-163
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• 2023

This study is situated in the context of intelligent transport systems, where in-vehicle devices assist drivers to avoid accidents and therefore improve road safety. The vehicles present in a given area form an ad' hoc network of vehicles called vehicular ad' hoc network. In this type of network, the nodes are mobile vehicles and the messages exchanged are messages to warn about obstacles that may hinder the correct driving. Node mobilities make it impossible for inter-node communication to be end-to-end. Recognizing this characteristic has led to delay-tolerant vehicular networks. Embedded devices have small buffers (memory) to hold messages that a node needs to transmit when no other node is within its visibility range for transmission. The performance of a vehicular delay-tolerant network is closely tied to the successful management of the nodes' transit buffer. In this paper, we propose a message transit buffer management model for nodes in vehicular delay tolerant networks. This model consists in setting up, on the one hand, a policy of dropping messages from the buffer when the buffer is full and must receive a new message. This drop policy is based on the concept of intermediate node to destination, queues and priority class of service. It is also based on the properties of the message (size, weight, number of hops, number of replications, remaining time-to-live, etc.). On the other hand, the model defines the policy for selecting the message to be transmitted. The proposed model was evaluated with the ONE opportunistic network simulator based on a 4000m x 4000m area of downtown Bouaké in Côte d'Ivoire. The map data were imported using the Open Street Map tool. The results obtained show that our model improves the delivery ratio of security alert messages, reduces their delivery delay and network overload compared to the existing model. This improvement in communication within a network of vehicles can contribute to the improvement of road safety.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.40.3-41
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• 2021

Minor mergers leave behind long lived, but extremely faint and extended tidal features including tails, streams, loops and plumes. These act as a fossil record for the host galaxy's past interactions, allowing us to infer recent accretion histories and place constraints on the properties and nature of a galaxy's dark matter halo. However, shallow imaging or small homogeneous samples of past surveys have resulted in weak observational constraints on the role of galaxy mergers and interactions in galaxy assembly. The Rubin Observatory, which is optimised to deliver fast, wide field-of-view imaging, will enable deep and unbiased observations over the 18,000 square degrees of the Legacy Survey of Space and Time (LSST), resulting in samples of potentially of millions of objects undergoing tidal interactions. Using realistic mock images produced with state-of-the-art cosmological simulations we perform a comprehensive theoretical investigation of the extended diffuse light around galaxies and galaxy groups down to low stellar mass densities. We consider the nature, frequency and visibility of tidal features and debris across a range of environments and stellar masses as well as their reliability as an indicator of galaxy accretion histories. We consider how observational biases such as projection effects, the point-spread-function and survey depth may effect the proper characterisation and measurement of tidal features, finding that LSST will be capable of recovering much of the flux found in the outskirts of L* galaxies at redshifts beyond local volume. In our simulated sample, tidal features are ubiquitous In L* galaxies and remain common even at significantly lower masses (M*>10^10 Msun). The fraction of stellar mass found in tidal features increases towards higher masses, rising to 5-10% for the most massive objects in our sample (M*~10^11.5 Msun). Such objects frequently exhibit many distinct tidal features often with complex morphologies, becoming increasingly numerous with increased depth. The interpretation and characterisation of such features can vary significantly with orientation and imaging depth. Our findings demonstrate the importance of accounting for the biases that arise from projection effects and surface-brightness limits and suggest that, even after the LSST is complete, much of the discovery space in low surface-brightness Universe will remain to be explored.