• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.2
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• pp.87-94
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• 2023

As the latest weapon systems and electronic equipments are increasingly demanding stealth technology to improve the survivability of allies, it is necessary to implement low-observability technology that reduces the radar cross section(RCS). In order to implement this stealth technology, a method for low RCS characteristics by applying a shape design or a electromagnetic wave absorber is widely used. However, active phased array antennas have structural limitations in shape design, also when a absorber is applied to it, the performance of the antenna is degraded. Therefore, in this paper, in order to realize the low RCS characteristics of the active phased array antenna operating in the X-band, individual radiating elements suitable for applying the radio wave absorber were selected, and a 13x13 array antenna was designed and manufactured. Next, by comparing the measured results of the relative RCS and electrical performance for the manufactured antenna according to the presence and type of the absorber, it is shown that the electrical performance is maintained at an equal or higher level while obtaining the low RCS characteristics. Thereby the method proposed in this paper for implementing the low RCS characteristics was validated. Finally, it was confirmed that when the wave absorber is applied to the array antenna, the limitation of its performance deterioration can be overcome.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.6
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• pp.241-249
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• 2022

This paper discusses the design of a ground clutter prevention fence for a radar wind profiler (RWP). The design point of the clutter fence is to improve the quality of the received signal by removing the non-weather clutter coming from the side. In this paper, a clutter prevention fence composed of a metallash mesh around the RWP is proposed, and the phase center of the antenna, the length, and height of the down fence, and the height and slop of the top fence through M&S are designed. The designed ground clutter prevention fence and 256 active phase array antennas were used as basic data. The effectiveness of the design was confirmed by a simulation. The side lobe in the ±90° direction was reduced by more than 30dB depending on the presence or absence of the designed ground clutter prevention fence. The fence was manufactured by 3D modeling, and the clutter shielding performance of approximately 20dB or more on the side of the antenna (±90°) was confirmed by applying it to the currently operated RWP.

• Journal of Marine Life Science
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• v.8 no.1
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• pp.1-7
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• 2023

This study was performed to understand the reproductive ecology of cephalopods, described the microanatomical structure of the male reproductive organs and spermatophore in the common squid, Todarodes pacificus, a major cephalopods in Korea. The common squid was gonochorism and had sexual dimorphism, the color of the reproductive organs reflected on the mantle and the presence of the hectocotylus. Male reproductive organs were composed of testis, primary vas deferens, spermatophoric gland (seminal vesicle), spermatophoric sac (Needham's sac) and secondary vas deferens. The male has specialized reproductive organs such as the spermatophore forming organ, spermatophoric gland. Testis was histologically a seminiferous tubule type. The primary vas deferens was a thin and inverted triangular spring-like form that connected from the rear of the testis to the spermatophoric gland. Inside, it was filled with sperm of basophilic in H-E stain. The spermatophoric gland is an irregular oval connected to the primary vas deferens and spermatophoric sac, and there were a number of tubular glands. The spermatophoric sac is a tubular structure located between spermatophoric gland and secondary vas deferens, and a number of spermatophores have been identified in the lumen. The secondary vas deferens was connected to the posterior of the spermatophoric sac and had a spermatophore inside. The spermatophore was a long, transparent tube about 22 mm long, with a sperm mass inside.

• Journal of Wetlands Research
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• v.25 no.2
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• pp.132-144
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• 2023

The use of constructed wetlands (CWs) to sequester carbon has been a topic of interest in recent studies. However, CWs have been found to be both carbon sinks and carbon sources, thus leaving uncertainties about their role in carbon neutrality initiatives. To address the uncertainties, a bibliometric and comprehensive review on carbon sequestration in CWs was conducted. Upon forming various scripts using CorText Manager, it was found that a majority of the studies focused on the effectiveness of CWs to remove nutrients, particularly nitrogen. The results of the comprehensive review revealed that high carbon concentrations and carbon sequestration rates in CW soils are dependent on the vegetation types used, the ages of the CWs, and the organic content of inflow water entering the CWs. The Typha genus was the most dominant plant genus used in the CWs from the reviewed studies and was associated with the highest carbon sequestration rates documented in this review study. Furthermore, the relatively high ability of tree species, in comparison to emergent plants, to sequester carbon was observed. Therefore, incorporating tree species into CW designs and adding them to emergent plants is seen as a potential breakthrough approach to improve the ability of CWs to sequester carbon and ultimately contribute to mitigating climate change.

• Science of Emotion and Sensibility
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• v.26 no.2
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• pp.13-24
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• 2023

This study tested whether the evaluation of moral cleansing behavior following an immoral act depends on the resources available to the wrongdoer. To this end, resource availability was manipulated by the wrongdoer's characteristics (socioeconomic status vs. physical health condition) and type of moral cleansing (donation vs. volunteer work), and participants rated the pain of the moral cleansing behavior, hypocrisy, and forgivability. Study 1 presents a scenario where a wrongdoer, either high or low in socioeconomic status, conducts moral cleansing via donation or volunteer work. Participants judged donation by those high in socioeconomic status to be not so painful, hypocritical, and unforgivable. Study 2 described a scenario in which a wrongdoer, either physically strong or weak, performs an act of moral cleansing either by donation or volunteer work. Participants considered those sickly wrongdoers' volunteer work to be painful, less hypocritical, and (compared with other conditions) more forgivable. Mediation analyses showed that in both Studies 1 and 2, pain in moral cleansing influenced the hypocrisy judgment which, in turn, affected perceived forgivability. These results indicate that, even for the same expiatory behavior, moral judgment depends on the actor's available resources. That is, people believe that moral cleansing should involve pain; otherwise, the act is hypocritical and unforgivable.

• The Korean Journal of Food And Nutrition
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• v.36 no.4
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• pp.327-333
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• 2023

This study investigated the antioxidant characteristics of sweet potato according to different plant parts and drying methods. The sweet potato plant parts were divided into root tubers, stems, stalks, leaves, and tips, and the drying methods were freeze-drying and hot air drying. Total polyphenol and flavonoid contents and radical scavenging activity of the sweet potato plant parts were significantly different depending on the plant parts and drying methods. The total polyphenol content of freeze-dried sweet potato leaves and tips were 52.76 and 46.19 mg chlorogenic acid equivalents/g sample, and the total flavonoid contents were 222.47 and 214.12 mg quercetin equivalents/g sample, respectively, and decreased with hot air drying. DPPH radical scavenging activity was higher in freeze-drying than hot air drying and was significantly different depending on the plant parts. The ABTS radical scavenging activity of freeze-dried sweet potato leaves and tips were 43.48 and 44.68 mg Trolox equivalents/g sample, respectively, and decreased with hot air drying. Therefore, additional studies on the functionality of using by-products from sweet potato cultivation are needed.

• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.2
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• pp.192-204
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• 2023

This study aimed to determine the criteria for quantifying developmental defects of enamel in primary teeth in premature babies and to investigate the severity of developmental defects according to the gestational age, birth weight, systemic complications, and treatments received after preterm birth. Birth information, a history of complications, the duration of parenteral nutrition, and endotracheal intubation were investigated by retrospectively reviewing the admission and discharge records of premature babies in the neonatal intensive care unit. The Preterm Developmental Defects of Enamel (PDDE) index was designed by modifying the existing developmental defects of enamel index. Based on PDDE index, the evaluator scored developmental defects of enamel by classifying them as enamel hypomineralization and hypoplasia. The PDDE scores in the extremely preterm and extremely low birth weight groups were significantly higher than those in other groups. Furthermore, PDDE scores of premature babies with bronchopulmonary dysplasia, rickets, intraventricular hemorrhage, or necrotizing colitis were significantly higher than those in the control group. In addition, more than 50 days of endotracheal intubation and more than 20 days of parenteral nutrition were associated with significantly higher PDDE scores than those in the control group and were risk factors for developmental defects of enamel. This study provides basic information for identifying risk factors for developmental defects of enamel in premature babies.

• Journal of Service Research and Studies
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• v.12 no.4
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• pp.125-138
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• 2022

This study has examined the effect of cognitive resource on purchase intention of scarcity products according to the level of need for cognitive closure. In order to find out the effect on purchase intention for products that are presented a shopping environment is supposed, where various timing of consumer promotion reward exist, and where consumers can easily access and experience a lot of cognitive changes. the effect of how these two influences are adjusted according to the level of need for cognitive closure (NFCC). The study divide into two experiments. Research analyzes the behavioral differences of consumers for scarcity message products according to cognitive resource level with a moderating effect of NFCC. As a result of the study, Research according to the level of cognitive resource, when applied scarcity message product showed a negative effect of the cognitive resource (self-regulating resource) depletion level on the purchase intention of high-involvement product with scarcity message (Hypothesis 1). Consumers' purchase intention for limited products was higher at the non-depleted level than at the cognitive resource depletion level, and this difference was found statistically significant. Next, as a result of examining the difference according to the level of NFCC, the difference in the influence of cognitive resource level on purchase intention of scarcity products was found to be statistically significant where the NFCC was low (Hypothesis 2).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.2
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• pp.219-230
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• 2023

Cities are continued to be highly advanced and metropolitanized. Lands adjacent to road make entry/exit connection increase along with construction of facilities for various purposes. However, in the absence of specific installation standards of entry and exit connection, inappropriate access location, types of access, and operation methods are deteriorating the level of traffic services at existing roads and intersections. Therefore, in order to minimize the traffic impact from entrances connected to minor arterial roads and colletor roads, first, this study re-established the waiting length in the intersection of upstream and downstream and length required for changing lanes and between entrance/exit and connection, considering the road and traffic environment in contact with the entrance. Second, it is suggested that the operation method depending on the connection type and whether to install left turn lane and acceleration and deceleration lane can be determined quantitatively by relation with the service level of nearby intersection after calculating the threshold amount of business site through negative social cost, which is the difference between the installation cost of the left turn lane and the acceleration and deceleration lane according to the type of access to the entrance and exit.

• Clean Technology
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• v.29 no.1
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• pp.22-30
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• 2023

Mongolia is experiencing some of the world's most serious air pollution problems. The air pollution is especially severe during the winter when raw coal and low-grade fuels are used to heat homes in Ger villages. The impact of this pollution has created significant health and socioeconomic challenges for the country. In order to mitigate this air pollution, this study analyzed the fuel quality of the low-grade fuels and Mongolian waste cooking oils used in Ulaanbaatar, Mongolia. Then the environmental characteristics of traditional stove combustion and a prototype combustion heating device were compared and analyzed. In addition, the effect of replacing the heating devices was evaluated by analyzing their risks to humans. Analysis of the fuel characteristics showed that briquettes had relatively low environmental properties as a result of their high ash, N and S content. Also, after analyzing the combustion characteristics, it was found that the air quality improvement effect was higher when waste cooking oil was burned compared to the three types of coal that were analyzed. Finally, this study evaluated the impact of replacing the Mongolia traditional stove with a prototype stove that uses waste cooking oil. The results of this study are expected to help to mitigate the air quality problems currently observed in Ulaanbaatar, Mongolia.