• Journal of Species Research
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• 제11권1호
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• pp.47-60
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• 2022

This study is based on crane fly specimens collected during more than 80 years, from 1937 through 2019, and are in collections maintained at the United States National Museum, Smithsonian Institution, Washington DC, USA; at Korea University collection, Seoul, South Korea, and the National Institute of Biological Resources, Incheon, South Korea. Three species belonging to genus Phylidorea Bigot, 1854 originally were described from North Korea and in total four species were known from the Peninsula. Phylidorea (Phylidorea) multidentata (Alexander, 1938) is a Korean endemic. We are adding P. (P.) melanommata (Alexander, 1921) to the list of Korean species, which was previously recorded from Japan and Far East of Russia. We present general information on genus and subgenera, redescriptions of species based on Korean specimens, illustrations of both sexes, elevation range, period of activity, habitat information, general distribution, and a distribution map for the Korean Peninsula (including North Korea) for each species.

• 식물분류학회지
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• 제50권3호
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• pp.356-360
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• 2020

A new distribution of Trichosanthes cucumeroides (Ser.) Maxim. ex Franch. & Sav. is discovered in Korea. This species was collected from forest margins on Ando Island, Ando-ri, Nam-myeon, Yeosu-si, in Jeollanam-do. T. cucumeroides is clearly distinguished from other species of the genus by having three- or five-lobed leaf blades, linear-lanceolate and minute bracts with entire margins, and oblong to triangular-ovoid seeds. Here, we provide precise description, a taxonomic key to the Korean Trichosanthes species, illustrations, and photographs of its habitat. The Korean name for the species is established as 'Bul-geun-ha-neul-ta-ri' considering the reddish color of its fruit.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2019년도 학술발표회
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• pp.160-160
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• 2019

Water is a limited source that needs to be properly managed and distributed to the ever-growing population of the world. Rapid urbanization and development have increased the overall water demand of the world drastically. However, there is loss of billions of liters of water every year due to leakages in water distribution systems. Such water loss means significant financial loss for the utilities as well. World bank estimates a loss of $14 billion annually from wasted water. To address these issues and for the development of efficient and reliable leakage management techniques, high efforts have been made by the researchers and engineers. Over the past decade, various techniques and technologies have been developed for leakage management and leak detection. These include ideas such as pressure management in water distribution networks, use of Advanced Metering Infrastructure, use of machine learning algorithms, etc. For leakage detection, techniques such as acoustic technique, and in recent yeats transient test-based techniques have become popular. Smart Water Grid uses two-way real time network monitoring by utilizing sensors and devices in the water distribution system. Hence, valuable real time data of the water distribution network can be collected. Best results and outcomes may be produced by proper utilization of the collected data in unison with advanced detection and management techniques. Long term reduction in Non Revenue Water can be achieved by detecting, localizing and repairing leakages as quickly and as efficiently as possible. However, there are still numerous challenges to be met and future research works to be conducted in this field.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(1)
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• pp.138-140
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• 2005

• 유통과학연구
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• 제21권9호
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• pp.81-91
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• 2023

Purpose: The article aims to assess the possibilities and contribution of countries to the creation and distribution of knowledge circulating in the scientific and technological space of the EAEU. Research design, data, and methodology: To understand the conditions and possibilities for the distribution of knowledge, the methodology of the quality of economic space used. The space is considered through density, placement, connectedness, and asymmetry. Used bibliometric analysis, balance of payments analysis, and integration indicators. Results: The study showed that low barriers, including language, created visible advantages in the mutual distribution of knowledge. However, the geo-technological space of the EAEU is polarised and has differences in the density and distribution of scientific resources. Asymmetries are shown in the distance between countries in multidirectional trends. Cooperation between countries has a different level of interaction. Conclusions: The internal resources of the geo-technological space of the EAEU are limited, and most of the needs are covered by external sources. Some mechanisms of the scientific policy of countries in scientific careers act as «demotivates» for distributing knowledge within the EAEU. Countries need to improve the quality of services and trade data to better understand technology distribution processes through bilateral channels.

• Structural Engineering and Mechanics
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• 제80권5호
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• pp.523-538
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• 2021

The mechanical behaviour and stability of coal mining engineering underground is significantly affected by ground water. In this study, nuclear magnetic resonance imaging (NMRI) technique was employed to determine the water distribution characteristics in coal specimens during saturation process, based on which the functional rule for water distribution was proposed. Then, using discrete element method (DEM), an innovative numerical modelling method was developed to simulate water-weakening effect on coal behaviour considering moisture content and water distribution. Three water distribution numerical models, namely surface-wetting model, core-wetting model and uniform-wetting model, were established to explore the water distribution influences. The feasibility and validity of the surface-wetting model were further demonstrated by comparing the simulation results with laboratory results. The investigation reveals that coal mechanical properties are affected by both water saturation coefficient and water distribution condition. For all water distribution models, micro-cracks always initiate and nucleate in the water-rich area and thus lead to distinct macro fracture characteristics. With the increase of water saturation coefficient, the failure of coal tends to be less violent with less cracks and ejected fragments. In addition, the core-wetting specimen is more sensitive to water than specimens with other water distribution models.

• Journal of Electrical Engineering and Technology
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• 제11권2호
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• pp.274-284
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• 2016

The increasing penetration of distributed energy resources on the distribution networks have brought a number of technical impacts where voltage and thermal variations have been identified as the dominant effects. Active network management in distribution networks aims to integrate distributed energy resources with flexible network management so that distributed energy resources are organized to make better use of existing capacity and infrastructure. This paper propose active solutions which aims to solve the voltage and thermal issues in a distributed manner utilizing a collaborative approach. The proposed algorithms have been fully tested on a distribution network with distributed generation units.

• 전력전자학회논문지
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• 제25권5호
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• pp.369-375
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• 2020

Distribution energy resources have been increasing in recent years. However, output power is limited for distribution network stability. This study proposes an active distribution network that can reconfigure distribution lines by using an active phase controller. A conventional distribution network has a fixed structure, whereas an active distribution network has a variable structure. Therefore, the latter can increase the output power of distribution energy resources and decrease the overload of distribution line facilities. An active phase controller has two operation modes for minimizing circulating current during dynamic reconfiguration. In this study, voltage and current control algorithms are proposed for active phase controllers. The simulation of the proposed methods for active phase controllers is performed using PSIM software.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.693-698
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• 2001

This paper establishes a coding method system including the liberation and size distribution of recycling materials in the shredder operation. Every particle in the shredded product becomes a code number using the liberation model and size distribution equation transforming of weight percentage into particles number percentage. One set of database can be obtained after all particles have been coded. This database is suitable for the size reduction operation in the process simulation of waste recycling. Coupling with the developed air classification, sizing and separating operations, the whole process simulation will be completely established for diversified application. A typical simulation for the rolling cutting shredder product of waste TV had been demonstrated under this coding system. The breakage size distribution of Gaudin and Schumann equation were selected for the shredding operation simulation. The Gaudin's liberation model was suitable fur the liberation simulation. Both of these equations were transformed weight percentage into particles distribution for the necessary of particle coding method. A better recycling operation for this shredded solid waste can be concluded from the comparison of simulation results with their sorted grade, recovery or economic of materials in different processes.

• Computers and Concrete
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• 제15권4호
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• pp.485-501
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• 2015

Cooling by the flow of water through an embedded cooling pipe has become a common and effective artificial thermal control measure for massive concrete structures. However, an extreme thermal gradient induces significant thermal stress, resulting in thermal cracking. Using a mesoscopic finite-element (FE) mesh, three-phase composites of concrete namely aggregate, mortar matrix and interfacial transition zone (ITZ) are modeled. An equivalent probabilistic model is presented for failure study of concrete by assuming that the material properties conform to the Weibull distribution law. Meanwhile, the correlation coefficient introduced by the statistical method is incorporated into the Weibull distribution formula. Subsequently, a series of numerical analyses are used for investigating the influence of the correlation coefficient on tensile strength and the failure process of concrete based on the equivalent probabilistic model. Finally, as an engineering application, damage and failure behavior of concrete cracks induced by a water-cooling pipe are analyzed in-depth by the presented model. Results show that the random distribution of concrete mechanical parameters and the temperature gradient near water-cooling pipe have a significant influence on the pattern and failure progress of temperature-induced micro-cracking in concrete.