• 인터넷정보학회논문지
• /
• 제21권2호
• /
• pp.19-26
• /
• 2020

This paper analyses the feasibility of using implantable antennas to detect and monitor tumors. We analyze this setting according to the wireless propagation loss and signal fading produced by human bodies and their environment in an indoor scenario. The study is based on the ITU-R propagation recommendations and prediction models for the planning of indoor radio communication systems and radio local area networks in the frequency range of 300 MHz to 100 GHz. We conduct primary estimations on 915 MHz and 2.4 GHz operating frequencies. The path loss presented in most short-range wireless implant devices does not take into account the human body as a channel itself, which causes additional losses to wireless designs. In this paper, we examine the propagation through the human body, including losses taken from bones, muscles, fat, and clothes, which results in a more accurate characterization and estimation of the channel. The results obtained from our simulation indicates a variation of the return loss of the spiral antenna when a tumor is located near the implant. This knowledge can be applied in medical detection, and monitoring of early tumors, by analyzing the electromagnetic field behavior of the implant. The tumor was modeled under CST Microwave Studio, using Wisconsin Diagnosis Breast Cancer Dataset. Features like the radius, texture, perimeter, area, and smoothness of the tumor are included along with their label data to determine whether the external shape has malignant or benign physiognomies. An explanation of the feasibility of the system deployment and technical recommendations to avoid interference is also described.

• 한국환경과학회지
• /
• 제29권9호
• /
• pp.885-905
• /
• 2020

This study described the characteristics of the upstream migration of salmon (Chum salmon, Oncorhynchus keta) along Yeon-gok Stream in the eastern coastal region of Korea from October 24 to November 9, 2018 using radio tag and data storage tag loggers for the detection of the locations of tagged salmon and measurement of water temperature. Tracking experiments were conducted and classified into four types (case 1 to case 4) depending on the release time and the number of salmon tracked. Experiments from case 1 to case 3 were classified depending on the number of salmon tracked into cases in which a single tagged salmon was tracked (case 1), a pair of tagged salmon was tracked (case 2), and salmon were tracked by different sex ratios (case 3). Experiments from cases 1 to 3 were conducted between 10 AM and 1 PM, and case 4 was conducted after 3:30 PM. Salmon moved and spawned in the downstream region of the Yeon-gok, where water temperature is higher than in other rivers and salmon return in Canada, Russia, Japan, and the U.S.A. Most of the radio-tagged salmon swam in deep and shaded areas during the day but actively moved upstream close to sunset, regardless of the release time. Females showed relatively more active movements than males during upstream migration.

• 한국콘텐츠학회논문지
• /
• 제12권2호
• /
• pp.388-397
• /
• 2012

최근 코스닥기업의 사이버 IR활동이 증가하고 있다. 이는 코스닥기업 입장에서 사이버 도구가 비용은 낮고 접근성은 높기 때문인 것으로 풀이된다. 따라서 본 연구에서는 사이버 IR을 실시한 코스닥기업을 대상으로 사이버 IR의 전반적인 효과를 검증하였다. 또한 사이버 IR을 실시한 기업의 대주주지분율 크기와 벤처기업 여부가 IR실시 이전기간(사전기간)과 이후기간(사후기간)에 주가(누적초과수익률)에 미치는 영향의 차이를 검증하였다. 분석결과는 다음과 같다. 첫째, 코스닥 기업은 IR 실시 전기간 동안 주가가 상승하는 것으로 나타났다. 이는 투자자들이 코스닥 기업의 IR활동을 사전적으로 호재로 인식하고 있기 때문인 것으로 풀이된다. 둘째, 대주주지분이 높은 집단에 비해 대주주지분이 낮은 집단의 초과수익률이 높게 나타났다. 대주주지분이 낮은 집단의 경우 투자자들을 의식한 보고행위와 감시제도가 효과적으로 그 기능을 수행하고 있음을 시사한다. 셋째, 코스닥 일반기업의 IR 실시효과보다 신기술을 기업 성장 및 발전의 기초로 삼고 있는 벤처기업의 IR 실시효과가 더 큰 것으로 나타났다.

• 통상정보연구
• /
• 제15권4호
• /
• pp.3-25
• /
• 2013

본 연구에서는 서비스 상품으로 미래 신 성장동력 산업인 의료관광산업의 육성과 개발이 시급한 실정이다. 현실은 관광과 의료가 융 복합 산업의 새로운 경제패러다임의 중추적 역할을 하는 산업으로 성장시키기 위한 실질적 의료관광 마케팅 전략수립의 기초적 근거를 제공하고자 연구의 목적을 두었다. 설문지는 한국의 방한한 의료관광자 중 상위 3개국(일본, 중국, 미국)을 대상으로 조사를 하였습니다. 수집된 자료를 근거하여 의료관광 목적시 각국의 의료 여행자 행동의 관계를 분석하였다 이에 대한 분석결과는 의료관광서비스품질(신뢰성, 유형성, 편리성)은 지각된 가치에 정(+)의 영향을 미치는 것으로 조사되었다. 또한 이들 요인 중(신뢰성, 유형성, 반응성, 편리성)은 감정적 가치에 정의 영향을 미치는 것으로 나타났다.

• 한국지반공학회논문집
• /
• 제21권8호
• /
• pp.45-53
• /
• 2005

강우에 의한 표면파괴는 세계적으로 흔히 볼 수 있는 사면파괴의 형태이다. 본 연구에서는 침투가 사면 표면의 안정에 미치는 영향을 평가하기 위해 일차원 침투모델을 이용한 무한사면 해석법을 연구하였다. 2층으로 구성된 지반에서 임의의 강우에 의해 유발되는 얕은 사면파괴의 가능성을 평가하기 위해서 Green-Ampt모델에 바탕을 둔 수정 GAML(Green-Ampt-Mein-Larson) 모델을 확장하여 재현기간에 따른 강우강도와 지속시간이 고려되는 침투거동을 예측하였다. 예측된 침투거동과 비교하기 위하여 일련의 수치해석이 수행되었다. 그 결과에 의하면 적절하게 선택된 입력값을 사용하면 제안된 간략법이 더욱 엄밀한 해석법인 유한요소해석과 근사한 합리적인 결과를 줌을 알 수 있다.

• Geomechanics and Engineering
• /
• 제25권3호
• /
• pp.195-205
• /
• 2021

Time effect on the deformation and strength characteristics of geogrid reinforced sand retaining wall has become an important issue in geotechnical and transportation engineering. Three physical model tests on geogrid reinforced sand retaining walls performed under various loading conditions were simulated to study their rate-dependent behaviors, using the presented nonlinear finite element method (FEM) analysis procedure. This FEM was based on the dynamic relaxation method and return mapping scheme, in which the combined effects of the rate-dependent behaviors of both the backfill soil and the geosynthetic reinforcement have been included. The rate-dependent behaviors of sands and geogrids should be attributed to the viscous property of materials, which can be described by the unified three-component elasto-viscoplastic constitutive model. By comparing the FEM simulations and the test results, it can be found that the present FEM was able to be successfully extended to the boundary value problems of geosynthetic reinforced soil retaining walls. The deformation and strength characteristics of the geogrid reinforced sand retaining walls can be well reproduced. Loading rate effect, the trends of jump in footing pressure upon the step-changes in the loading rate, occurred not only on sands and geogrids but also on geogrid reinforced sands retaining walls. The lateral earth pressure distributions against the back of retaining wall, the local tensile force in the geogrid arranged in the retaining wall and the local stresses beneath the footing under various loading conditions can also be predicted well in the FEM simulations.

• International Journal of Computer Science & Network Security
• /
• 제23권2호
• /
• pp.199-202
• /
• 2023

Carriage return (CR) and line feed (LF), also known as CRLF injection is a type of vulnerability that allows a hacker to enter special characters into a web application, altering its operation or confusing the administrator. Log poisoning and HTTP response splitting are two prominent harmful uses of this technique. Additionally, CRLF injection can be used by an attacker to exploit other vulnerabilities, such as cross-site scripting (XSS). Email injection, also known as email header injection, is another way that can be used to modify the behavior of emails. The Open Web Application Security Project (OWASP) is an organization that studies vulnerabilities and ranks them based on their level of risk. According to OWASP, CRLF vulnerabilities are among the top 10 vulnerabilities and are a type of injection attack. Automated testing can help to quickly identify CRLF vulnerabilities, and is particularly useful for companies to test their applications before releasing them. However, CRLF vulnerabilities can also lead to the discovery of other high-risk vulnerabilities, and it fosters a better approach to mitigate CRLF vulnerabilities in the early stage and help secure applications against known vulnerabilities. Although there has been a significant amount of research on other types of injection attacks, such as Structure Query Language Injection (SQL Injection). There has been less research on CRLF vulnerabilities and how to detect them with automated testing. There is room for further research to be done on this subject matter in order to develop creative solutions to problems. It will also help to reduce false positive alerts by checking the header response of each request. Security automation is an important issue for companies trying to protect themselves against security threats. Automated alerts from security systems can provide a quicker and more accurate understanding of potential vulnerabilities and can help to reduce false positive alerts. Despite the extensive research on various types of vulnerabilities in web applications, CRLF vulnerabilities have only recently been included in the research. Utilizing automated testing as a recurring task can assist companies in receiving consistent updates about their systems and enhance their security.

• Structural Engineering and Mechanics
• /
• 제84권2호
• /
• pp.155-165
• /
• 2022

The use of electricity and communication between electronic devices is increasing daily, which makes the stability of electrical power supply vital. Since the 1990s, large earthquakes have occurred frequently causing considerable direct damage to electrical power facilities as well as secondary damage, such as difficulty in restoring functions due to the interruption of electric power supply. Therefore, it is very important to establish measures to protect electrical power facilities, such as transformers and switchboards, from earthquakes. In this study, a 154 kV transformer whose service life had expired was installed on the base fabricated by simulating the field conditions and conducting the shaking table tests. The dynamic characteristics and seismic behavior of the 154 kV transformer were analyzed through the resonance frequency search test and seismic simulation test that considers the front, rear, left, and right directions. Since the purpose of this study is to analyze the acceleration amplification in the bushing due to the acceleration amplification, the experimental results were analyzed focusing on the acceleration response and the converted acceleration amplification ratio rather than the failure due to the displacement response of the transformer. The seismic force amplification at the transformer bushing was evaluated by simulating the characteristics of electrical power facilities in South Korea, and compared with the IEC TS 61463 acceleration amplification factor. Finally, the amplification factor at zero period acceleration (ZPA) modified for each return period was summarized. The results of this study can be used as data to define the amplification factor at ZPA of the transformer bushing, simulating the characteristics of electrical power facilities in Korea.

• 보건행정학회지
• /
• 제33권3호
• /
• pp.338-354
• /
• 2023

Background: The influence of social capital on the spread of coronavirus disease 2019 (COVID-19) and related behaviors and perceptions has been recognized during the COVID-19 pandemic. This study aims to analyze the trends in social capital using primary data from the Korean Community Health Survey, which is the only available source in Korea for local-level social capital analysis. It also investigates the relationship between various variables, including social capital, as factors influencing COVID-19-related behaviors and perceptions. Methods: The study analyzed the temporal trends of social capital using raw data from four community health surveys conducted in 2017, 2019, 2020, and 2021. A multilevel analysis was conducted to examine the relationship between social capital and COVID-19-related behaviors and perceptions following the onset of the COVID-19 pandemic in 2020. Results: Social capital consists of trust, bonding social capital, and bridging social capital. Within the trust sub-factor, trust in neighbors (Trust-1) declined after the COVID-19 pandemic, whereas trust in safety and general environment (Trust-2) and trust in medical services and public transportation (Trust-3) increased. Additionally, the gap between municipalities narrowed. COVID-19-related behaviors and perceptions, such as adherence to COVID-19 prevention measures, return to normal activities, and fear of COVID-19, showed improvement in 2021 compared to the previous year. Individual-level trust in neighbors was associated with reduced fear of COVID-19, while community-level trust in neighbors was associated with increased fear of COVID-19. Conclusion: Social capital plays a role in mitigating public health crises, and it is necessary to implement active policies that address the gap in social capital between metropolitan and rural areas. Strengthening risk communication regarding emerging infectious diseases such as COVID-19 is crucial.

• 아태비즈니스연구
• /
• 제15권2호
• /
• pp.207-222
• /
• 2024

Purpose - This study investigates whether the lagged price difference ratio between preferred and common stocks is related to the return and closing price of the preferred stock using three panel models. Design/methodology/approach - As a first step, we use a two-way fixed effect panel model with stationary preferred stock returns as a dependent variable. For robustness, we then apply the autoregressive distributed lag model (ARDL) and error correction model (ECM) with nonstationary closing prices of the preferred stocks as a dependent variable and compare the results of each model. The ARDL and ECM models provide an advantage of estimating a long-run equilibrium equation together if a long-run relationship exists between the two time-series variables compared to the fixed effect model. Findings - Our sample consists of 107 preferred stocks with at least four years of daily observations as of the end of December 2023. The coefficients of the error correction terms in the ARDL and ECM models are highly statistically significant, approximately -0.08. This indicates that the disequilibrium between the closing prices of common and preferred stocks adjusts by about 8% per day toward equilibrium. In all three models, the price difference ratio on day t-1 was statistically significant in explaining the preferred stock returns or closing prices on day t, implying that trading based on the previous day's price difference ratio is effective for one day. Research implications or Originality - Furthermore, the returns on preferred stocks are higher for firms with a lower proportion of foreign investors or a lower foreign market capitalization of preferred stocks. This suggests that foreign investors with informational advantages do not actively engage in profit-taking by trading preferred stocks, thus not narrowing the price difference. In summary, the recent surge in preferred stock prices is likely driven mainly by the irrational behavior of retail investors.