• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.3
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• pp.1-13
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• 2021

Effects of the nozzle wall angles on the supersonic flow field in a thrust optimized nozzle were numerically investigated. The combustor and operating condition of 30-tonf rocket engine was selected to study the optimum nozzle shape. The nozzle flow of combustion products was realized by the shifting equilibrium calculation for the propellant of kerosene-LOx. The change of nozzle wall angles induced different developing patterns of the internal and secondary shock wave. The optimum nozzle was obtained when the internal shock was in a specific position at the nozzle outlet. The nozzle wall angles of the optimum nozzle were very similar to those of the optimum nozzle which does not consider the shock wave.

• East Asian Economic Review
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• v.26 no.2
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• pp.119-142
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• 2022

This paper uses social network theory and the internationalization process model (IPM) to determine how external network linkages influence the location choices of multinational enterprise from emerging economies (EMNEs); specifically, whether past alliance experience influences location choices and its impact on the subsequent entry of MNEs from emerging economies. This paper applies survival analysis using initial and secondary investments from 2,000 Chinese A-share listed companies that entered 90 countries between 1997 and 2018 to analyze both the initial and subsequent entries of Chinese outward foreign direct investments (OFDIs) in major host countries. The findings indicate that an MNE's previous experience with a company from a particular country will increase the likelihood of an initial investment in that country. Previous alliance experience may accelerate the foreign investment process of EMNE and stimulate firms making a commitment to a position in a foreign network, regardless of cultural distance and stage of internationalization. Alliance before initial investment may increase the likelihood and speed of entering a host country as wholly owned subsidiaries and that network linkages not only significantly influence the internationalization process of small and medium-sized enterprises, as indicated by the IPM, but also that of large listed firms.

• International Journal of Computer Science & Network Security
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• v.23 no.3
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• pp.94-100
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• 2023

The primary goal of any communication spacecraft is to provide communication in variety of frequency bands based on mission requirements within the Indian mainland. Some of the spacecrafts operating in S-band utilizes a 6m or larger aperture Unfurlable Antenna (UFA for S-band links and provides coverage through five or more S-band spot beams over Indian mainland area. The Unfurlable antenna is larger than the satellite and so the antenna is stowed during launch. Upon reaching the orbit, the antenna is deployed using motors. The deployment status of any deployment mechanism will be monitored and verified by the telemetered values of micro-switch position before the start of deployment, during the deployment and after the completion of the total mechanism. In addition to these micro switches, a camera onboard will be used for capturing still images during primary and secondary deployments of UFA. The proposed checkout system is realized for validating the performance of the onboard camera as part of Integrated Spacecraft Testing (IST) conducted during payload checkout operations. It is designed for acquiring the payload data of onboard camera in real-time, followed by archiving, processing and generation of images in near real-time. This paper presents the architecture, design and implementation features of the acquisition, processing and Image generation system for Camera onboard spacecraft. Subsequently this system can be deployed in missions wherever similar requirement is envisaged.

• Journal for History of Mathematics
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• v.35 no.1
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• pp.19-39
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• 2022

This paper aims to examine how the public perception of mathematics changed in England in the 19th century. As rapid industrial and social developments took place in the 19th century, the educational environment underwent great changes, and the value and public perception of mathematics also changed. Mathematics took a new position in the terrain of educational reform in the late 19th century. In this study, I analyzed the actual condition of mathematics education in elementary and secondary schools, popular educational institutions, and universities in England in the first half, middle, and second half of the 19th century, and compared what values and usefulness of mathematics education were justified in each institution. I also examined how satirical magazine Punch satirized the public understanding or view on mathematics at each period. It is to be hoped that this study will have significant implications for raising the public's positive perception of mathematics in modern society.

• Steel and Composite Structures
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• v.47 no.3
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• pp.315-337
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• 2023

The steel structure is an assembly of individual structural members joined together by connections. The connections are the focal point to transfer the forces which is susceptible to damage easily. It is challenging to replace the affected connection parts after an earthquake. Hence, steel plates are utilised as a structural fuse that absorbs connection forces and fails first. The objective of the present research is to develop a beam-column end plate connection with single and dual fuse and study the effect of single fuse, dual fuse and combined action of fuse and damper. In this research, seismic resilient beam-column end plate connection is developed in the form of structural fuse. The novel connection consists of one main fuse was placed horizontally and secondary fuse was placed vertically over main fuse. The specimens are fabricated with the variation in number of fuse (single and dual) and position of fuse (beam flange top and bottom). From the fabricated ten specimens five specimens were loaded monotonically and five cyclically. The experimental results are compared with Finite Element Analysis results of Arunkumar and Umamaheswari (2022). The results are critically assessed in the aspect of moment-rotation behaviour, strain in connection components, connection stiffness, energy dissipation characteristics and ductility. While comparing the performance of total five specimens, the connection with fuse exhibited superior performance than the conventional connection. An equation is proposed for the moment of resistance of end-plate connection without and with structural fuse.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.136-138
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• 2022

Edge detection includes information such as the shape, position, size, and material of an object with respect to an image, and is a very important factor in analyzing the characteristics of the image. Existing edge detection methods include Sobel edge detection filter, Roberts edge detection filter, Prewitt edge detection filter, and LoG (Lapacian of Gaussian) using secondary differentials. However, these methods have a disadvantage in that the edge detection results are somewhat insufficient because a fixed weight mask is applied to the entire image area. Therefore, in this paper, we propose an edge detection algorithm that increases edge detection characteristics by considering the center pixel in the mask. In addition, in order to confirm the proposed edge detection performance, it was compared through simulation result images.

• Journal of English Language & Literature
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• v.56 no.6
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• pp.1191-1210
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• 2010

This article claims that English liquid consonants are characterized by the presence of complex place nodes, regardless of dialectal varieties. The primary difference between rhotic and laterals can be pursued in a phonological sense. The level of subbranching nodes is in charge of the disparities among two types of liquids: the branching immediately below the Coronal node with laterals, while branching at the secondary sublevel with rhotics. In this context, the processes of rhotic deletion and lateral vocalization can be understood as those motivated to get rid of complex place nodes. That is, those processes take place as part of phonological attrition. Next, the onset/coda asymmetry regarding liquids stems from the dispreference of vocoid at the onset position, which is readily accounted for by the series of constraints on the well-formedness on the onset, namely Harmonic Onset. The rationale of gradualness and harmonic improvement proposed by Harmonic Serialism is useful to separate the attested outputs from unattested ones across the whole gamut of English varieties. All in all, the primary benefits of our analysis can be found in the consistence in the explanation for the operations running through the sounds regarded as belonging to liquid consonants, comprising the whole range of rhotic and lateral consonants.

• Journal of IKEEE
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• v.27 no.4
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• pp.411-417
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• 2023

Unmanned aerial vehicle (UAV)-assisted relay has the advantages of ease of deployment, good communication channels, and mobility over traditional terrestrial relay, which greatly improves wireless connectivity. In this paper, we design a UAV-enabled relay network that can utilize radio frequency bands to harvest energy from sources and utilize terahertz (THz) bands to transmit information between secondary transmitters and receivers. Next, we solve the optimal position of the UAV that maximizes the relay channel capacity, and propose an algorithm to design two trajectories of UAV (a straight and an elliptical trajectory) using the derived solution. Numerical results show that the straight trajectory is better in terms of harvested energy and channel capacity.

• Journal of Species Research
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• v.13 no.2
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• pp.185-254
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• 2024

Sixteen species of Asterocheres collected from the southern and eastern coasts of Korea are recorded. Two species are redescriptions-Asterocheres aesthetes Ho, 1984 and A. siphonatus Giesbrecht, 1897. The remaining 14 new species described are A. geminus n. sp., A. processus n. sp., A. culicis n. sp., A. eurychelatus n. sp., A. scutellatus n. sp., A. spiniventer n. sp., A. fici n. sp., A. serratus n. sp., A. tridentatus n. sp., A. nodulosus n. sp., A. tetraodontis n. sp., A. dokdoicus n. sp., A. exilis n. sp., and A. zodius n. sp. These new species are compared with other known species of the genus mainly based on the character states of 17 selected characters. These characters include the length/width ratios of the caudal ramus and genital double-somite, the number of postgenital lateral setules or spinules on the genital double-somite of the female, the number of segments of the antennule of both sexes, the position of aesthetasc on antennular segments in the female, the relative length of terminal claw of the antenna, the relative length of the oral siphon, the number of segments and the relative length of the mandibular palp, the presence or absence of inner coxal seta on legs 1 and 4, the relative lengths of setae on the exopod of female leg 5, the presence or absence of sexual dimorphisms of swimming legs, and the presence or absence of a secondary aesthetasc on the male antennule. A key to 22 species of Asterocheres known in Korea waters is provided.

• Clinical Endoscopy
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• v.55 no.1
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• pp.141-145
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• 2022

A 44-year-old woman underwent sleeve gastrectomy, which was complicated by a leak. She was treated with two sessions of endoscopic internal drainage using plastic double-pigtail stents. Her clinical evolution was favorable, but four months after the initial stent placement, she became symptomatic, and a gastrobronchial fistula with the proximal end of the stents invading the diaphragm was diagnosed. She was treated with antibiotics, plastic stents were removed, and a partially covered metallic esophageal stent was placed. Eleven weeks later, the esophageal stent was removed with no evidence of fistula. Inappropriate stent size, position, stenting duration, and persistence of low-grade inflammation could explain the patient's symptoms and provide a mechanism for gradual muscle rupture and fistula formation. Although endoscopic internal drainage is usually safe and effective for the management of post-laparoscopic sleeve gastrectomy leaks, close clinical and radiological follow-up is mandatory.