• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.7
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• pp.1148-1157
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• 2022

The maritime safety act defines a large vessel as a vessel of at least 200m in length overall. Since this standard was introduced in 1986, it has not been revised even though the marine traf ic environment has changed significantly. The length overall of 200m is equivalent to the handymax class for a dry bulker; therefore, classifying this as a modern large vessel size is difficult. Meanwhile, according to the maritime safety act, the specific sea area for traffic safety is established where large vessels frequently pass. Accordingly, by reviewing maritime-related laws, this study confirmed that standards for vessels larger than 200m in length overall were already introduced. Furthermore, by examining the statistics of vessels entering Korean ports, the existence of sea areas with a lot of traffic by large vessels, except the current 5 specific areas, was confirmed. Therefore, the following were suggested: the deletion of the term large vessel, a raise in the standard for length of a vessel related to a specific sea area in the maritime safety act.

• The Journal of the Acoustical Society of Korea
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• v.42 no.5
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• pp.403-411
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• 2023

Functional ultrasound imaging, such as elasticity imaging and micro-blood flow Doppler imaging, enhances diagnostic capability by providing useful mechanical and functional information about tissues. However, the implementation of functional ultrasound imaging poses limitations such as the storage of vast amounts of data in Radio Frequency (RF) data acquisition and processing. In this paper, we propose a sub-Nyquist approach that reduces the amount of acquired axial samples for efficient shear-wave elasticity imaging. The proposed method acquires data at a sampling rate one-third lower than the conventional Nyquist sampling rate and tracks shear-wave signals through RF signals reconstructed using band-pass filtering-based interpolation. In this approach, the RF signal is assumed to have a fractional bandwidth of 67 %. To validate the approach, we reconstruct the shear-wave velocity images using shear-wave tracking data obtained by conventional and proposed approaches, and compare the group velocity, contrast-to-noise ratio, and structural similarity index measurement. We qualitatively and quantitatively demonstrate the potential of sub-Nyquist sampling-based shear-wave elasticity imaging, indicating that our approach could be practically useful in three-dimensional shear-wave elasticity imaging, where a massive amount of ultrasound data is required.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.1247-1248
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• 2022

Due to rapid urbanization and population growth, it has become crucial to analyze the various volumes and characteristics of pedestrian pathways to understand the capacity and level of service (LOS) for pathways to promote a better walking environment. Different indicators have been developed to measure pedestrian volume. The pedestrian level of service (PLOS), tailored to analyze pedestrian pathways based on the concept of the LOS in transportation in the Highway Capacity Manual, has been widely used. PLOS is a measurement concept used to assess the quality of pedestrian facilities, from grade A (best condition) to grade F (worst condition), based on the flow rate, average speed, occupied space, and other parameters. Since the original PLOS approach has been criticized for producing idealistic results, several modified versions of PLOS have also been developed. One of these modified versions is perceived PLOS, which measures the LOS for pathways by considering pedestrians' awareness levels. However, this method relies on survey-based measurements, making it difficult to continuously deploy the technique to all the pathways. To measure PLOS more quantitatively and continuously, researchers have adopted computer vision technologies to automatically assess pedestrian flows and PLOS from CCTV videos. However, there are drawbacks even with this method because CCTVs cannot be installed everywhere, e.g., in alleyways. Recently, a technique to monitor bio-signals, such as electrodermal activity (EDA), through wearable sensors that can measure physiological responses to external stimuli (e.g., when another pedestrian passes), has gained popularity. It has the potential to continuously measure perceived PLOS. In their previous experiment, the authors of this study found that there were many significant EDA responses in crowded places when other pedestrians acting as external stimuli passed by. Therefore, we hypothesized that the EDA responses would be significantly higher in places where relatively more dynamic objects pass, i.e., in crowded areas with low PLOS levels (e.g., level F). To this end, the authors conducted an experiment to confirm the validity of EDA in inferring the perceived PLOS. The EDA of the subjects was measured and analyzed while watching both the real-world and virtually created videos with different pedestrian volumes in a laboratory environment. The results showed the possibility of inferring the amount of pedestrian volume on the pathways by measuring the physiological reactions of pedestrians. Through further validation, the research outcome is expected to be used for EDA-based continuous measurement of perceived PLOS at the alley level, which will facilitate modifying the existing walking environments, e.g., constructing pathways with appropriate effective width based on pedestrian volume. Future research will examine the validity of the integrated use of EDA and acceleration signals to increase the accuracy of inferring the perceived PLOS by capturing both physiological and behavioral reactions when walking in a crowded area.

• Environmental and Resource Economics Review
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• v.31 no.4
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• pp.755-775
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• 2022

This study empirically analyzes that the asymmetry of domestic gasoline price adjustment to the crude oil price changes can vary depending on the level of gasoline price using quantile autoregressive distributed lag model. The data used are the weekly average Dubai price, domestic gasoline price at refiners and gas stations from the first week of May 2008 to the second week of October 2022. The study estimates three price transmission channels: changes in gas station gasoline prices in response to changes in Dubai oil prices, changes in refiners gasoline prices in response to changes in Dubai oil prices, and changes in gas station prices relative to refiners gasoline prices. As a result, the price adjustment of refiner's gasoline price with respect to Dubai oil price appears asymmetrically across all quantiles of gasoline price, whereas the adjustment of gas station prices for Dubai oil price and refiner's gasoline price tend to be more asymmetric as the quantile of gasoline price increases. Such a result is presumed to be due to changes in the inventory cost of gas stations. When the burden of inventory cost is high, gas stations have an incentive to more actively pass the increased buying price on their selling price.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.1
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• pp.55-61
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• 2023

This study aims to develop CLSM fill material for emergency restoration using landfill coal ash. As a result of examining physical properties such as particle size distribution and fines content of landfill coal ash, bottom ash, fly ash, and general soil were mixed, and SP was found to have a density of 2.03 and a residual particle pass rate of 7.8 %. CLSM materials that secure fluidity in unit quantities without using chemical admixtures such as glidants and water reducing agents have a high risk of material separation due to bleeding. As a result of this experiment, it was found that the bleeding ratio did not satisfy the standard in the case of the specimen with a large amount of fly ash and a lot of addition of mixing water. As a result of the compressive strength test, the strength development of 0.5 MPa or more for 4 hours was found to be satisfactory for the specimens using hemihydrate gypsum with a unit binder amount of 200 or more, and the remaining gypsum showed poor strength development. Although it is judged that landfill coal ash can be used as a CLSM material, it is necessary to identify and apply the physical and chemical characteristics of coal ash buried in the ash treatment plant of each power generation company.

• Journal of the Korean Geotechnical Society
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• v.26 no.5
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• pp.37-48
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• 2010

In this study, the seepage flow monitoring method by the hydraulic head loss rate was developed for the purpose of application to offshore construction site enclosed by cofferdams in which seepage force varies periodically. The amount of the hydraulic head loss rate newly defined in this graph was in a range between 0 and 1. The zero of the rate means the existence of flow with no seepage resistance. The 1 of the rate means no seepage flow through the ground. The closer to 1 the coefficient of determinant in the hydraulic head loss graph is, the more the ground through which seepage water flows is stable. The closer to 0 the coefficient of determinant in the hydraulic head loss graph is, the more the ground through which seepage water flows was unstable and the higher the possibilities of existence of empty space or of occurrence of piping on the seepage flow pass in the ground is. The hydraulic head loss graph makes it possible to monitor sensitively the situation of seepage flow state, and the graph helps to understand easily the seepage flow state at the specific section on the whole cofferdam.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.3
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• pp.27-33
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• 2023

Countries around the world are calling for stronger law enforcement to combat the production and distribution of child sexual exploitation images, such as child grooming. Given the scale and importance of this social problem, it requires extensive cooperation between law enforcement, government, industry, and government organizations. In the wake of the Nth Room Case, there have been some amendments to the Enforcement Decree of the Telecommunications Business Act regarding additional telecommunications services provided by precautionary operators in Korea. While Naver and others in Korea use Electronics and Telecommunications Research Institute's own technology to filter illegal images, Microsoft uses its own PhotoDNA technology. Microsoft's PhotoDNA is so good at comparing and identifying illegal images that major global operators such as Twitter are using it to detect and filter images. In order to meet the Korean government's testing standards, Microsoft has conducted more than 16 performance tests on "PhotoDNA for Video 2.0A," which is being applied to the Bing service, in cooperation with the Korea Communications Commission and Telecommunications Technology Association. In this paper, we analyze the cases that did not pass the standards and derive improvement measures related to adding logos. In addition, we propose to use three video datasets for the performance test of filtering against illegal videos.

• Analyses & Alternatives
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• v.2 no.1
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• pp.31-69
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• 2018

This study examines the role of science in resolving trade disputes. After the Great East Japan Earthquake of 11 March 2011 that not only jeopardized the people of Japan, but also put the safety of an entire region at risk, the Republic of Korea (Korea) has imposed import bans as well as increased testing and certification requirements for radioactive material on Japanese food products. Japan has challenged these restrictions at the World Trade Organizations Dispute Settlement Body (DSB). This study aims to explain how international trade agreements and previous DSB rulings have dealt with different scientific viewpoints provided by confronting parties. In doing so, it will contrast the viewpoints espoused by Korean and Japanese representatives, and then analyzes the most similar case studies previously ruled on by the DSB, including the case of beef hormones and the case of genetically modified crops including biotech corn, both between the United States and the European Communities (EC). This study finds that science is largely subordinate to national interests in the case of state decision-making within the dispute settlement processes, and science has largely been relegated to a supportive role. Due to the ambiguity and lack of truly decisive decisions in the Appellate Body in science-based trade disputes, this study concludes that the Appellate Body avoids taking a firm scientific position in cases where science is still inconclusive in any capacity. Due to the panel's unwillingness to establish expert review boards as it has the power to do, instead favoring an individual-based system so that all viewpoints can be heard, it has also developed a system with its own unique weaknesses. Similar to any court of law in which each opposing party defends its own interests, each side brings whatever scientific evidence it can to defend its position, incentivizing them to disregard scientific conclusions unfavorable to their position. With so many questions that can arise, combined with the problems of evolving science, questions of risk, and social concerns in democratic society, it is no wonder that the panel views scientific information provided by the experts as secondary to the legal and procedural issues. Despite being ruled against the EC on legal issues in two previous cases, the EC essentially won both times because the panel did not address whether its science was correct or not. This failure to conclusively resolve a debate over whose science is more scientific enabled the EC to simply fix the procedural issues, while continuing to enforce trade restrictions based on their scientific evidence. Based on the analysis of the two cases of disputes, Korea may also find itself guilty of imposing an unwarranted moratorium on Japan's fish exports, only to subsequently pass new restrictions on labelling and certification requirements because Japan may have much scientific evidence at its disposal. However, Korea might be able to create enough uncertainty in the panel to force them to rule exclusively on the legal issues of the case. This will then equip Korea, like the EC in the past, with a way of working around the ruling, by changing whatever legal procedure they need to while maintaining some, if not most, of its restrictions when the panel fails to address its case on scientific grounds.

• Korean Journal of Heritage: History & Science
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• v.56 no.2
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• pp.282-294
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• 2023

Efforts are being made internationally to pay attention to the landscape value of modern and contemporary heritage and to pass it on. However, in Korea, the registration of modern and contemporary landscape heritage as registered cultural properties is insignificant. There has also been little discussion on ways to improve the system in this regard. This study sought ways to improve the registration criteria and classification system of the registered cultural property system so that modern and contemporary landscaping heritage could be protected. Currently, the registration criteria for registered cultural properties are not stipulated for each type of heritage, but are stipulated as a single comprehensive standard. Registration criteria should be separately prepared so that the landscape value of the heritage can be reviewed. First, the registration criteria have an important value in understanding the development of landscape culture. Second, well-preserved landscaping reflects or characterizes the times. Lastly, it should be defined as related to the works of major artists or important figures or historical events. The classification system must match the studied building cultural property classification system, and the detailed types of modern and contemporary landscape heritage should be specified. The major classification follows the building cultural property classification system, but parks and green spaces, squares, and gardens, which can be called a single landscape heritage, should be added to the middle classification. Landscaping heritage, such as gardens combined with building heritage, shall be specified in the subcategory based on building use.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2D
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• pp.127-134
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• 2010

Tunnel sections on the highway are different from rest of sections on the highway in terms of velocity, the number of passing cars, and vehicle density which, in particular, affect drivers' behavior before and after drivers pass through the tunnel. However, literature review reveals that former studies are too focused on quantitative indicator to consider qualitative aspects. Therefore, this paper conducts survey questionnaire and IPA (Importance Performance Analysis) to find out qualitative improvements on velocity drop on the tunnel sections. The results show as follows: First, drivers require improvements of tunnel form (length and curved form inside tunnel) which is derived from long distance tunnel. Second, experts primarily ask for amendment of geometric characteristics. With comparison of requirements of both drivers and experts, there are many differences in length of tunnel and form of curved tunnel. This also presents that drivers don't satisfy with both length of tunnel and form of curved tunnel that are provided as a part of highway design factors.