Earticle

본 논문에서는 기계적 결함에 따른 실제 진폭비와 명목상 진폭비의 차이를 정규분포를 갖는 랜덤변수로 모델링할 때, crosse-eye의 재밍 효과의 성능 분석을 다룬다. 수치 적분 기반 접근법을 사용하여 구한 mean square difference (MSD)를 제안한다. 수치 적분 기반 접근법을 사용하여 구한 MSD는 1차 테일러 근사 기반 성능 분석 방법과 2차 테일러 근사 기반 해석적 성능 분석 방법을 이용하여 계산한 analytic 기반 MSD보다 근사 하지 않은 Monte-Carlo 기반 Simulation MSD에 가깝다. 이는 수치 적분 기반 MSD가 정확성이 더 높은 것을 뜻한다. 계산비용이 큰 Monte-Carlo 기반 Simulation을 이용하지 않아도 수치적분을 통하여 MSD로 주어지는 진폭비 섭동이 성능 저하에 미치는 영향을 구할 수 있음을 보인다.

This paper deals with the performance analysis of the jamming effect of cross-eye when the difference between the real amplitude ratio and the nominal amplitude ratio due to mechanical defects is modeled as a random variable with a normal distribution. We propose how to evaluate mean square difference (MSD) obtained using a numerical integration-based approach. The MSD obtained by the proposed method is closer to non-approximated Monte-Carlo simulation-based MSD than the analytic MSD calculated using the first-order Taylor approximation and the second-order Taylor approximation. It is shown that, based on the numerical integration, the effect of amplitude ratio perturbation on the cross-eye jamming performance can be evaluated without going through the computationally intensive Monte-Carlo method.

본 논문에서는 지면반사를 이용한 크로스아이 재밍에 의해서 발생되는 모노펄스 레이다의 추적오차를 분석한 다. 크로스아이 재밍은 위상과 진폭이 다른 두 신호를 동시에 레이다로 송신하여 레이다 추적 시스템에 오차를 발생 시키는 방법이다. 모노펄스 레이다가 지형 바운스에 의해서 발생되는 크로스 아이 재밍신호를 수신하면 고각 방향으 로 추적오차가 발생 한다. 다중반사가 존재하는 저고도 환경에서 추적 레이다 수신기에서는 재머에서 송신된 신호가 직접 경로와 반사 경로 두 신호가 도달하여 그 경로 차에 의해 오차가 발생한다. 지형 바운스 재밍은 단일 재머를 이용하여 할 수 있는 장점이 있으나 재밍에 영향을 미치는 공간은 지형 반사각과 지형의 산란 정도에 의해서 제한된 다. 본 연구는 해상에서 저고도로 날아오는 미사일이나 항공기로부터 함정을 보호하기 위해서 유용하게 활용될 수 있을 것으로 판단된다.

In this paper, the tracking error of monopulse radar caused by cross-eye jamming using terrain bounce is analyzed. Cross-eye jamming is a method of generating an error in a radar tracking system by simultaneously transmitting two signals with different phases and amplitudes. When the monopulse radar receives the cross-eye jamming signal generated by the terrain bounce, a tracking error occurs in the elevation direction. In the presence of multipath, this signal is a combination of the direct target return and a return seemingly emanating from the target image beneath the terrain surface. Terrain bounce jamming has the advantage of using a single jammer, but the space affecting the jamming is limited by the terrain reflection angle and the degree of scattering of the terrain. This study can be usefully used to protect ships from low-altitude missiles or aircraft in the sea.

본 논문에서는 크로스아이 재머의 위상차와 진폭비 및 조우각을 제어하여 모노펄스 레이다의 추적 거리오 차를 분석하였다. 크로스아이 재밍은 모노펄스 레이다의 중요한 재밍 방법으로 레이다 수신안테나의 입력에 변위 를 유발하여 레이다의 추적 각도를 오도시킨다. 모노펄스 레이다와 재머 사이의 조우각을 변화시키면서 레이다의 추적 거리오차를 분석한 결과 조우각이 0◦이고 위상차가 180◦ 일 때 최대 거리오차가 발생하며 조우각이 45◦∼ 135◦가 되면 거리오차가 최대 거리오차의 70% 이하로 감소하는 것을 확인하였다. 재머의 효율을 높이기 위해서는 회전 재머나 다수 채널 재머에 대한 연구가 필요하며, 본 연구는 항공기 및 함정의 크로스아이 재머 설계에 유용하 게 활용될 것으로 판단된다.

In this paper, we analyzed the tracking error for the monopulse radar by controlling the phase difference, amplitude ratio and engagement angle of the cross-eye jammer. Cross-eye jamming is an important jamming method for monopulse radars, which causes a displacement in the radar receiving antenna input and misleads the radar's tracking angle. As a result of analyzing the tracking distance error of the radar while changing the engagement angle between the monopulse radar and jammer, the maximum distance error occurs when the engagement angle is 0◦ and the phase difference is 180◦. It was confirmed that the error decreased to 70% or less of the maximum distance error into 45◦∼135◦. In order to increase the efficiency of jammers, it is necessary to study rotary jammers or multi-channel jammers. This study will be very useful for the design of cross-eye jammers for aircraft and ships.

본 논문은 2세트의 크로스 아이 재머 안테나가 십자형으로 배치되어 모노펄스 레이다를 재밍하는 경우 재머의 위상차와 진폭 비 및 레이다 조우각도에 따른 재밍 효과를 분석하였다. 크로스 아이 재머의 위상차와 진폭 비는 재머에서 조정이 가능하지만 조우각도는 레이다에 의해서 상대적으로 결정되기 때문에 조우각도 변화에 따른 재머의 대응이 매우 중요하다. 수직 교차된 2세트의 크로스 아이 재머 안테나는 하드웨어 구성을 최소로 하면서 재밍 효과를 높일 수 있는 좋은 방법으로 판단되며, 조우각도를 0◦∼360◦ 변화시키면서 재밍 효과를 분석하였다. 본 재머는 단일 재머와 비교하여 조우각도 45◦∼135◦와 225◦∼315◦에서 재밍 효과가 크게 향상되며, 항공기 및 함정의 크로스 아이 재머 설계에 유용하게 활용될 것으로 판단된다.

In this paper, when two sets of cross-eye jammer antennas are installed vertically to jam a monopulse radar, the jamming effects according to the jammer's phase difference, amplitude ratio, and radar angle of engagement are analyzed. The phase difference and amplitude ratio of the cross-eye jammer can be adjusted in the jammer, but since the angle of engagement is relatively determined by the radar, it is very important to respond to changes in the angle of engagement. The orthogonally deployed jammer antennas can be considered as a good way to increase the jamming effect while minimizing the hardware configuration, and the jamming effect is analyzed while changing the angle of inclination from 0◦ to 360◦. This jammer greatly improves the jamming effects at the angles of incidence 45◦∼135◦ and 225◦∼315◦, compared to a single jammer. And it is expected to be useful in the design of cross-eye jammers for military aircraft and ships.

본 논문에서는 cross-eye의 두 재밍 안테나의 진폭 불일치로 인한 성능 저하를 고려한다. 진폭비의 불일치 는 기계적 결함에 따른 실제 진폭비와 명목상 진폭비의 차이가 정규분포를 갖는 랜덤변수로 모델링한다. 1차 테일러 전개와 2차 테일러 전개를 통한 해석적 성능분석이 제안된다. 실제 진폭비와 명목상 진폭비의 불일치가 발생한 Cross-eye 재밍의 성능 측정은 mean square difference (MSD)를 계산함으로서 측정된다. 해석적으로 유도된 MSD는 1차 테일러 전개 기반 시뮬레이션 기반 MSD 및 2차 테일러 전개 기반 시뮬레이션 기반 MSD와 해석 기반 MSD와 비교함으로써 검증된다. 계산비용이 높은 Monte-Carlo기반 MSD보다 해석 기반 MSD가 우수함을 보인다.

In this paper, performance degradation in the cross-eye jamming due to amplitude mismatch of two jamming antennas is considered. The mismatch of the amplitude ratio is modeled as a random variable with a normal distribution of the difference between the actual amplitude ratio and the nominal amplitude ratio due to mechanical defects. In the proposed analytic performance analysis, the first-order Taylor series expansion and the second-order Taylor series expansion is adopted. Performance measure of the cross-eye jamming is the mean square difference (MSD). The analytically derived MSD is validated by comparing the analytically derived MSD with the first-order Taylor series-based simulation-based MSD and the second-order Taylor series-based simulation-based MSD. It shows that the analysis-based MSD is superior to the Monte-Carlo-based MSD, which has a high calculation cost.

Purpose: This study explored the threat and efficacy factors influencing children’s eye health behaviors using an Extended Parallel Process Model for parents of preschool chil- dren. Methods: Data were collected from October 30 to November 6, 2023, using a web-based survey. In total, 166 parents of preschool children participated in this cross-sectional study. Data were analyzed using Pearson’s correlation coefficients and multiple regres- sion analyses. Parents’ eye health knowledge, eye health threat factors (perceived severi- ty and susceptibility), and eye health efficacy factors (self-efficacy and response efficacy) related to preschoolers were measured. Eye health behavior was assessed by observing the children’s behavior over the past week. Results: The eye health behaviors of preschool children were positively correlated with their parents’ eye health knowledge (r=.21, p=.006), perceived severity (r=.22, p=.004), re- sponse efficacy (r=.36, p<.001), and self-efficacy (r=.64, p<.001). Children’s eye health be- havior showed a negative correlation with perceived susceptibility (r=-.27, p<.001). As seen on multiple regression analysis, the factor influencing children’s eye health behav- ior was self-efficacy (β=.57, p<.001), and the model’s explanatory power was approxi- mately 43% (F=24.09, p<.001). Conclusion: To promote eye health behavior in preschool children, it is necessary to strengthen the self-efficacy of parents. The results of this study can be used to develop eye health programs for preschool children and their parents

Purpose: This study aimed to identify the factors affecting dry eye syndrome and quality of life (QoL) among college students. Methods: This cross-sectional study administered a descriptive survey to 184 college students across Korea. Data collection was conducted from August 27 to 28, 2024, using an online survey platform (Google Forms). The self-reported survey comprised the Health-Related Quality of Life Instrument with 8 Items scale, the Dry Eye Questionnaire 5, and the Ocular Surface Disease Index. Data analysis was performed using SPSS version 27.0. Results: The participants had a mean age of 21.37 (standard deviation 1.96) years. Regression analysis identified sleep satisfaction, vision-related functions, and dry eye symptoms as statistically significant predictors of QoL, accounting for 18.4% of the variance (F = 14.71, p < .001). Dry eye symptoms were significantly influenced by the use of artificial tears, vision-related functions, and environmental factors, which accounted for 41.3% of the variance (F = 43.93, p < .001). Additionally, significant determinants of ocular surface disease included the use of vision correction tools, the presence of ophthalmic diseases, sleep satisfaction, and dry eye symptoms. These factors explained 45.7% of the variance, confirming the model's robustness (F = 31.84, p < .001). Conclusion: It is necessary to identify strategies to alleviate dry eye syndrome in college students and develop comprehensive prevention and management programs to improve their QoL.

본 논문에서는 재귀형 크로스아이(retrodirective cross-eye) 재머 신호와 레이다 반사 신호 비(Jamming and radar return Signal Ratio: JSR)에 따른 모노펄스 레이다의 추적 오차의 변화를 분석하였다. 레이다 추적 오차를 계산하기 위한 방법으로 크로스아이 재머 이득(Gc)이 사용되었고, 재머 이득과 재머 신호와 레이다 반사 신호의 비(JSR)의 관계를 수식으로 표현하였다. 모노펄스 레이다와 재머 사이의 조우각과 JSR을 동시에 변화 시키 면서 레이다 추적 오차를 분석하였다. 그리고 재머 두 신호간의 위상(Φ) 차이와 JSR의 변화를 분석 한 결과 두 재머 신호 위상 차이가 180◦에 가까워질수록 추적 오차가 커지고 JSR이 20dB이상이 되면 추적 오차가 일정 수준 을 유지하게 되는 것을 볼 수 있다. 본 연구는 레이다 반사 신호의 비(JSR)에 따른 모노펄스 레이다의 추적 오차에 대한 결과를 제시하였고 추적 방향, 두 재머 신호 위상차, 두 재머 신호 크기 비율 등에 따른 복합적인 추적오차 분석 결과를 제시하였다.

In this paper, we analyze the tracking errors of monopulse radar according to the JSR of retrodirective cross-eye and radar skin return signals. The cross-eye jammer gain(Gc) is used to calculate the radar tracking errors, and the relationship between the jammer gain and the JSR is represented mathematically. We analyze the radar tracking errors by varying the tracking angle and JSR. Analysis results of the phase difference(Φ) and amplitude ratio(a) between the two jammer signals and the changing JSR show that the closer the phase difference of the two jammer signals is to 180, the greater the tracking error and it shows that if the JSR is above 20dB, the tracking errors no longer increase. This work presents an effective utilization of retrodirective cross-eye jammers through various tracking error analyses based on the JSR, tracking angles, two-jammer phase differences and amplitude ratios of two-jammer signals.

본 연구는 미국과 한국의 통합교육 현장에서 야기될 수 있는 교사들의 지도과정에서“눈 맞춤 역할”이 어떤 현상으로 양국 간에 차이를 나타내는지에 대한 다문화 교사태도와 관련된 질적 분석 연구이다. 연구의 진행은 미국과 한국의 유아 및 초등 저학년 수준의 자폐아동들을 지도하는 교사 약 70명을 대상으로 직접관찰 및 면담방법을 사용하였다. 연구결과의 분석은 문화비교분석기법을 활용하였다. 연구의 결과는 2가지로 구분하여 제시될 수 있다. 첫째, 미국문화에서의 교사지도 관점은 우선 발달지체 유아나 아동들의 학습향상을 위해서는 적극적으로“눈 맞춤 하기”가 유익한 것으로 판단하여 이를 위한 최선의 노력을 기울인다는 사실이다. 둘째, 한국의 교사들은 발달지체 유아나 아동들에 대한 지도 관점을 우선 눈 맞춤에 두지 않고, 다만 발달지체 자체가 유아나 아동들이 지닌 눈 맞춤 기능을 저하시키고 있음으로 이는 어쩔 수 없는 것으로 간주하여“눈 맞춤하기 지도”자체에 크게 신경 쓰지 않는다는 사실이다. 본 연구에서의 결과를 바탕으로 한 결론은 다음과 같다. 첫째, 한국과 미국문화 자체가 발달지체 유아 혹은 아동과의 눈 맞춤에 대한 학습지도상의 중요성이 다르게 지각되고 있음으로 한국의 경우에는 유아 혹은 아동에 대한 학습능력향상이 가능한 방향으로 개선되어야 한다. 둘째, 본 연구는 교사들의 지도방향에 따라 유ㆍ아동들의 눈 맞춤기능이 향상가능하다고 분석하였다. 따라서 교사와 아동의 눈 맞춤 빈도 증가 여부는 교사의 적극적 지도 관점에 따라 차이를 나타낼 수 있다. 고로 눈 맞춤 기능 증가 수준의 향상은 유ㆍ아동의 교과학습능력 향상에 상당부분 기여할 수 있을 것이다.

This study is a cross-cultural qualitative analysis of educators in selected inclusive education classrooms at selected sites in the United States and South Korea. It examines how educators interpret the eye contact of students labeled with autism. The social requirements for, and interpretation of, non-verbal communicative behaviors differ between the U. S. and South Korea. The study is based on 70 interviews with educators who have experience with students labeled with autism in inclusive classrooms at preschool and elementary levels in both countries. The data analysis uses the constant comparative method. Many of the American teachers we interviewed indicated the importance of teaching students labeled with autism to make eye contact; whereas, most of the Korean teachers interviewed did not mention the importance of making eye contact as much as American teachers. Many of the American teachers we interviewed observed the improvement in making eye contact, and a couple of teachers mentioned students’improvement of the frequency of eye contact. The study reveals that the teachers’perception of the importance of making eye contact is different between the United States and South Korea. The importance of making eye contact is related to particular cultural requirements. Also, the frequency of making eye contact can be improved according to how students are educated.

This paper challenges previous K-pop studies on fandom in South Korea to broaden their focus beyond straight-identified fans to include queer fans. Although previous studies have focused on male K-pop stars as the object of heterosexual desire, the phenomenon of “fan cosplay,” or “fancos” for short, demonstrates that these male stars also serve as a means for cross-gender identification for female fans. This paper explores K-pop’s role as a space for its young female fans to explore gender and sexual identity, as well as its influence on local queer subculture in terms of gendered styling, gendered pairing, and queer terminology. Furthermore, an examination of the historical changes in the popularity of fancos reveals the transformation in the recognition of homosexuality and its backlash in Korea as well as the strategies of the queer subculture to focus on invisibility and in-group differentiation. Therefore, a queer perspective on K-pop studies includes domestic queer fans in the study of K-pop, complicates the heteronormative assumptions of fandom studies, and the relationship between commercial media and desire and sheds light on sexual politics in South Korea.

Objective The visual system plays a crucial role in regulating sleep by providing cues that synchronize the circadian rhythm. Consequently, ophthalmic diseases?particularly diabetic retinopathy (DMR), age-related macular degeneration (AMD), epiretinal membrane (EM), and glaucoma?may influence sleep duration through circadian disruption and disease-related psychological stress. However, large-scale studies examining the relationship between these conditions and sleep duration remain limited. This study investigated these associations in a nationwide, population-based sample.Methods This cross-sectional study analyzed data from the 2019 and 2020 the Korea National Health and Nutrition Examination Survey. Ophthalmic diseases were diagnosed through fundoscopy, and sleep duration on weekdays and weekends was self-reported. The study included 8,395 participants aged 40 years or older who underwent fundoscopy. Statistical models were adjusted for demographic and clinical covariates, including age, sex, body mass index, and comorbidities.Results Patients with DMR and EM had significantly reduced sleep duration, with reductions of 0.3 hours to 0.5 hours on weekdays and weekends compared to individuals without these conditions. No significant differences in sleep duration were observed for AMD or glaucoma. After covariate adjustment, the associations between shorter sleep duration and DMR or EM remained significant.Conclusion This nationwide population-based study using fundus photography revealed that DMR and EM are significantly associated with reduced sleep duration, while AMD and glaucoma are not. These findings suggest a differential sleep impact by disease type and support the need for targeted evaluation and management of sleep in patients with ophthalmic diseases. Further research is warranted to clarify underlying mechanisms and guide public health strategies.

Background: Atopic dermatitis (AD) is an inflammatory skin disorder characterized by relapsing eczema with intractable itching. Ocular diseases in patients with AD, including cataract, retinal detachment, blepharitis, glaucoma, keratoconjunctivitis, and keratoconus, have frequently been reported worldwide. However, only a few studies using a large-sample, population-based study design have been reported so far. Objective: We investigated the association between cataract, glaucoma, and dry eye disease and AD in an adult population in the Republic of Korea. Methods: A total of 14,900 adults who participated in the Korean National Health and Nutrition Examination Survey, a nationwide, population-based, cross-sectional survey, between 2010 and 2012 were included in the study. Multiple logistic regression analyses identified the possible association between cataract, glaucoma, and dry eye disease and AD relative to matched controls. Results: After we adjusted for confounding factors in patients with AD, cataract and glaucoma were significantly associated with AD. Moreover, patients with AD had a higher prevalence of ophthalmic surgery compared to those without AD. Conclusion: Dermatologists should therefore be aware of possible ocular disorders in patients with AD and should recommend regular ophthalmic screening for early detection.

One of the effective methods for angular deception against monopulse radar is a cross eye technique. The typical cross eye technique can cause significant angular errors to monopulse radar by using two transceivers which transmit the signals with opposite phases. However, typical cross eye systems have high complexity of implementation because two transceivers should be installed with enough distance on the platform. In this paper, we propose a new cross eye technique with single transceiver based on the multipath effect. Then, angular deception performance of the proposed technique is analyzed.

Cross eye technique was proposed as an angle deception jamming technique against monopulse radars. Tracking radars use monopulse or conical scan methods for angle estimation of a target. Thus, if we verify deception performance of cross eye technique against a conical scan radar, efficient jamming systems can be developed to disturb both monopulse radars and conical scan radars. In this paper, we propose a mathematical model for a conical scan radar and a cross eye system. Using the proposed model, angular deception performance of the cross eye technique against conical scan radar is analyzed.

모노펄스 센서는 수신된 단일 펄스마다 목표물의 각도를 추정한다. 이러한 모노펄스 센서의 각도 추정을 기만하기 위한 방법으로는 크로스 아이 기법이 효과적인 것으로 알려져 있다. 본 논문에서는 크로스 아이 기법의 각도기만 성능을 확인하기 위해 무반향 챔버에 모노펄스 수신 안테나와 크로스 아이 송신기를 이용해 각도기만 시험 환경을 구성한 결과를 소개한다. 그리고 시험 구성을 이용하여 두 개의 크로스 아이 송신기 간격을 변화시키면서 모노펄스 수신 안테나에 인가되는 합 신호와 차 신호의 크기를 측정하고, 그에 해당하는 각도기만 성능을 분석한다.

A monopulse sensor is used to estimate the angle of a target with respect to each received single pulse. It is well known that the cross-eye technique can result in an angle deception effect against monopulse sensors. To verify this effect, we propose a test environment configuration for the angle deception using monopulse receiving antennae and cross-eye transmitters in an anechoic chamber. Using the proposed test environment configuration, we have measured powers of the sum and difference of the signals received by the monopulse receiving antennae when the distance of the two cross-eye transmitters is varied. Finally, the angle deception performance related to the powers of the sum and difference signals was analyzed.

목적: 한국 성인에서 갑상선 이상과 건성안의 관계를 밝히고자 하였다. 대상과 방법: 제5기 국민건강영양조사(2012) 자료를 이용하여 건성안 검진을 받은 총 16,966명을 대상으로 갑상선 이상과 건성안의 연관성을 다변량 로지스틱 회귀분석을 이용해 분석하였다. 결과: 대조군과 비교하였을 때, 건성안군에서 여성, 도시지역 거주 비율이 높았고, 소득수준이 낮았으며, 비흡연자, 비음주자 비율이 높았고, 체질량지수가 낮았으며, 고혈압, 고지혈증, 갑상선 이상, 갑상선질환, 갑상선암 유병률이 높았다. 유의한 모든 변수를 포함한 다변량 로지스틱 회귀분석 결과상 갑상선 이상(odds ratio [OR], 1.93; 95% confidence interval [CI], 1.43-2.61), 갑상선질환(OR, 1.85; 95% CI, 1.37-2.52), 갑상선암(OR, 2.45; 95% CI, 1.06-5.67)이 모두 건성안과 유의한 연관성을 보였다. 또한 성별로는 여성에서갑상선 이상(OR, 2.02; 95% CI, 1.47-2.76), 갑상선질환(OR, 1.93; 95% CI, 1.41-2.65), 갑상선암(OR, 2.62; 95% CI, 1.06-6.62)이 건성안과 유의한 연관성을 보였으나, 남성에서는 이러한 연관성이 유의하지 않았다. 결론: 갑상선 이상, 갑상선질환, 갑상선암은 건성안의 위험인자로 고려될 수 있으며, 특히 여성환자 진찰 시 갑상선 이상에 대해 더 주의 깊은 관찰 및 평가가 필요할 것으로 생각된다.

Purpose: To investigate the relationship between thyroid abnormality and dry eye syndrome (DES) in a nationally representative Korean population. Methods: A population-based prospective cross-sectional study was conducted, using the thyroid abnormality data set of the Korean National Health and Nutrition Examination Survey, 2010 - 2012. A total of 16,966 Korean participants with DES were enrolled in the study. Results: The DES patients were predominantly women, non-smokers and non-drinkers, living in urban regions, with a low income and body mass index (BMI), and with a higher percentage of hypertension, hyperlipidemia, thyroid abnormalities, thyroid diseases, and thyroid cancers. After adjusting for all significant variables, thyroid abnormality (odds ratio [OR], 1.93; 95% confidence interval [CI], 1.43-2.61), thyroid disease (OR, 1.85; 95% CI, 1.37-2.52), and thyroid cancer (OR, 2.45; 95% CI, 1.06-5.67) were significantly associated with DES. There was also a significant association between DES and thyroid abnormalities (OR, 2.02; 95% CI, 1.47-2.76), thyroid diseases (OR, 1.93; 95% CI, 1.41-2.65), and thyroid cancer (OR, 2.62; 95% CI, 1.06-6.62) in the female group, but there was no significant association in the male group. Conclusions: Thyroid abnormalities, thyroid diseases, and thyroid cancers were associated with DES in a nationally representative Korean population. Close evaluation of thyroid abnormalities is therefore needed when treating female patients.