센서 측정기와 회로형 순환 유닛(GRU)을 이용한 실내 공기 품질 측정 및 추세 예측 시스템

안재현,신동일,김규호,양지훈,Ahn, Jaehyun,Shin, Dongil,Kim, Kyuho,Yang, Jihoon 한국정보처리학회 2017 정보처리학회논문지. 소프트웨어 및 데이터 공학 Vol.6 No.9

실내 공기 품질 측정은 측정 대상 공간의 대기 상태 유지, 외부 변인으로 인한 대기 이상 현상을 검출하려는 방법이다. 실내 공기 품질을 주기적으로 기록하면서 변인에 따른 공기 변화에 특정 패턴이 발생함을 관측할 수 있었으나, 파라미터를 설정하고 계수를 찾아 나가기엔 파라미터의 개수나 그 영향력을 추산하기 어렵고 결과가 시간에 의존적이라는 문제가 있다. 따라서 본 실험은 이것을 공식화하는 대신, 측정 주기마다 추이를 예측하는 관측치 중심의 기계 학습 모델을 개발하는 것을 목표로 한다. 본 논문은 실내 대기 품질을 주기적으로 전송 및 저장하는 측정기의 기록 데이터로 공기 품질 변화를 예측하는 모델을 설명하고 시계열 분석 모델을 구축한다. Indoor air quality analysis is conducted to understand abnormal atmospheric phenomena and the external factor affecting indoor air quality. By recording indoor air quality measurements periodically, we are able to observe patterns in air quality. However, it difficult to predict the number of potential parameters, set parameters for a given observation and find the coefficients. Moreover, the results are time-dependent. Thus to address these issues, we introduce a microchip capable of periodically recording indoor air quality and a model that estimates atmospheric changes based on time series data.

갑상선 미세유두상암의 임상적 특성

안재현,최재영<SUP>1<.SUP>,박원서,송정윤,김용호,이상목,고석환,Jae Hyun Ahn,M.D.,Jae Young Choi,M.D.<SUP>1<.SUP>,Won Seo Park,M.D.,Jeong Yoon Song,M.D.,Yong Ho Kim,M.D.,Sang Mok Lee,M.D. and Suck Hwan Koh,M.D. 대한갑상선-내분비외과학회 2008 The Koreran journal of Endocrine Surgery Vol.8 No.2

<B>Purpose:</B> PTMC is defined as a papillary thyroid cancer smaller than 10 mm in its greatest diameter. It is the most common form of differentiated thyroid cancer and its prognosis is known to be very favorable. The aim of this study is to identify its biologic behavior and to formulate a reasonable therapeutic strategy for the treatment of PTMC. <B>Methods:</B> 379 patients with papillary thyroid cancer were analyzed. Each patient was diagnosed preoperatively or postoperatively and treated between Jan. 2000 and Dec. 2007. Among these patients, 143 had been identified as having PTMC (37.7%) with a mean tumor size of 0.72 cm in diameter. <B>Results:</B> There were no significant differences of the clinical characteristics such as gender, age, the operative methods, or multicentricity between the PTMC group and the non-PTMC group, except for LN metastases. Also, there were fewer symptoms of palpable neck mass and preoperative findings such as capsular invasion and microcalcification in the PTMC group. We performed unilateral lobectomy with or without central compartment neck node dissection for the early stage diseases, but for the later stages of disease we performed near-total or total thyroidectomy with routine central compartment neck node dissection. And for the patients with lateral node enlargement, we performed ipsilateral modified radical neck dissection (MRND). <B>Conclusion:</B> This study shows that PTMC is quite similar to conventional papillary thyroid cancer in its biological behavior, and we conclude that total thyroidectomy with central compartment neck node dissection is the proper therapeutic strategy to treat PTMC. However, further study is necessary for identifying the low-risk and high-risk patients with PTMC. <B>(Ko</B><B></B><B>rean J Endocrine Surg 2008;8:101-105)</B>

경쟁 기반 MAC에서의 반복적 톤 기반 경쟁 기법

안재현,윤정균,박세웅,Ahn, Jae-Hyun,Yun, Jeong-Kyun,Bahk, Sae-Woong 한국통신학회 2007 韓國通信學會論文誌 Vol.32 No.5A

IEEE 802.11의 DCF는 경쟁 기반 방식으로 폴링 기반 방식의 PCF에 비해 알고리즘이 단순하고 나쁘지 않은 성능을 보여주기 때문에 실질적으로 많이 쓰이고 있다. 하지만 DCF는 경쟁을 통하여 채널을 할당받기 때문에 데이터 전송 시에 다른 노드들과 충돌의 위험이 있다. 이러한 충돌을 줄이기 위해서 CSMA/CA의 충돌 회피 방식을 사용하지만 그 성능에는 한계가 있다. 본 논문에서는 이런 문제를 해결하기 위해 톤을 사용한 새로운 경쟁 기법 TAR(Tone-based Access scheme with Repetitive contention)를 제안한다. TAR에서는 데이터 전송 채널(data transmission channel)외에도 적은 구간의 경쟁 채널(contention channel)을 두어 데이터 전송과 경쟁을 병렬적으로 처리함으로써 기존의 CSMA/CA가 가지고 있는 충돌에 대한 문제를 줄이고자 하였다. 경쟁 기법의 큰 개념은 기존의 CSMA/CA 기법을 이용하지만 경쟁 채널이라는 개념을 도입하여 반복적인 경쟁을 통해 데이터 전송 채널에서의 충돌 확률을 크게 줄이는 장점이 있다. 제안한 TAR 기법은 모의실험을 통해 기존의 기법에 비해 크게 좋은 성능을 보임을 확인하였다. There are two coordination functions in IEEE 802.11 standard. One is PCF, polling based function, and the other is DCF, contention based function. DCF is simpler than PCF but the performance is similar with the latter. That's the reason why DCF is more popular than PCF. However, DCF has a risk of collision with other nodes in the network because the function is a distributed contention based one. CSMA/CA of DCF has collision avoidance algorithm in it, but the performance of avoidance algorithm has limitations. In this paper we proposed a new scheme called TAR(Tone-based Access scheme with Repetitive conention). In TAR, there is narrow contention-only channel other than original data transmitting channel, so that both a data transmission and the contention can be performed simultaneously. The TAR uses the same contention concept with the CSMA/CA, but it has the originality for the narrow contention channel and the repetitive contention scheme which greatly reduce the collision probability. We proved the performance of TAR by some simulations, and it showed good results.

전기화학적 도금을 이용한 wrap-around 게이트 나노구조의 제작

안재현,홍수헌,강명길,황성우,Ahn, Jae-Hyun,Hong, Su-Heon,Kang, Myung-Gil,Hwang, Sung-Woo 한국전기전자학회 2009 전기전자학회논문지 Vol.13 No.2

To overcome short channel effects, wrap-around field effect transistors have drawn a great deal of attention for their superior electrostatic coupling between the channel and the surrounding gate electrode. In this paper, we introduce a bottom-up technique to fabricate a wrap-around field effect transistor using silicon nanowires as the conduction channel. Device fabrication was consisted mainly of electron-beam lithography, dielectrophoresis to accurately align the nanowires, and the formation of gate electrode using electrochemical deposition. The electrolyte for electrochemical deposition was made up of non-toxic organic-based solution and liquid nitrogen was used as a method of maintaining the shape of polymethyl methacrylate(PMMA) during the process of electrochemical deposition. Patterned PMMA can be used as a nano-template to produce wrap-around gate nano-structures. Wrap-around 전계효과 트랜지스터는 채널과 전극간의 커플링을 매우 커서 채널길이가 짧아지면서 생기는 단채널효과(short channel effect)를 개선시킬 수 있는 이유로 많은 관심을 불러왔다. 본 논문에서는 실리콘 나노와이어를 이용하여 상향식의 wrap-around 전계효과 트랜지스터(FET)의 제작 공정을 소개한다. 소자의 제작 공정은 크게 전자빔 리소그래피, 유전영동(dielectrophoresis)을 이용한 나노와이어의 효과적 정렬 그리고 게이트 전극의 전기 화학적 도금(electrochemical deposition)을 이용한 생성 등의 방법들로 이루어진다. 전기 화학적 도금을 위한 용액은 독성을 띄지 않는 유기물 용액을 사용하였다. 액체 질소를 이용하여 polymethyl methacrylate(PMMA)가 전기화학적 도금시 형태를 잃지 않게 함으로써, 패터닝된 PMMA가 wrap-around 게이트 나노구조를 제작하기 위한 나노 템플릿으로 사용될 수 있도록 하였다.

도시침수 대응 및 복구계획 수립 연구

안재현,김학열,유승혁,Ahn,Jae-Hyun,Kim,Hag-Yeol,Yoo,Seung-Hyuk 한국방재학회 2008 한국방재학회 학술발표대회논문집 Vol.2008 No.1

Response and recovery plan is necessary to protect against urban flood which can cause damage on property and human life. In this research, urban flood response and recovery plans were studied to improve an establishment method for local autonomous entities. The result of this research will be applied to make a manual for forming response and recovery plan in Korea.

화재 예방을 위한 태양광 접속반의 지능형 진단 시스템

안재현,양오,Ahn, Jae Hyun,Yang, Oh 한국반도체디스플레이기술학회 2021 반도체디스플레이기술학회지 Vol.20 No.3

To prevent accidents caused by changes in the surrounding environment or other factors, various protection facilities are installed at the photovoltaic connection module. The main causes of fire are sparks due to foreign substances inside the photovoltaic connection module through high temperature rise and dew condensation in the photovoltaic connection module, and fire due to heat from the power diode. The proposed method can predict the fire by measuring flame, carbon dioxide, carbon monoxide, temperature, humidity, input voltage, and current on the photovoltaic connection module, and when the fire conditions are reached, fire alarm and power off can be sent to managers and users in real time to prevent fire in advance.

골다공증 한약제제 임상시험 참여자의 골다공증 한의치료에 대한 인식 : 질적 연구

안재현,조예은,김지혜,이승훈,강중원,이재동,Ahn, Jae-hyun,Cho, Ye-eun,Kim, Ji-hye,Lee, Seung-hoon,Kang, Jung-won,Lee, Jae-dong 대한한방내과학회 2017 大韓韓方內科學會誌 Vol.38 No.2

Objective: This research aimed to understand patients' perceptions of Korean medicine treatment for osteoporosis in a clinical trial setting. Methods: Ten patients participating in a clinical trial of a herbal medicine drug for osteoporosis were invited to an interview. Data were collected by in-depth interviews and patient observations. This qualitative study adopted the case study research method, and within-case and cross-case analyses were conducted. Results: A model of the patients' osteoporosis management planning was derived from the study. The results showed that the patients' perceptions of osteoporosis were derived from their knowledge and experience during diagnosis and treatment of the condition. Two groups of patients were recognized: those who overlooked the importance of osteoporosis and those who recognized the importance of osteoporosis. Before making treatment decisions about osteoporosis, the patients evaluated the treatment options and weighed the advantages and disadvantages of each option. When evaluating their treatment, the patients combined their knowledge and experience of Korean and western medicine treatments. Their experience of participating in the clinical trial influenced the management planning of osteoporosis. Two major reasons for low compliance with osteoporosis treatment were ignorance of the disease and insufficient information provided by doctors. Conclusion: The results of this qualitative study pointed to four strategies that could be employed to improve accessibility to Korean medicine treatment for osteoporosis: the dissemination of comprehensive information on osteoporosis in the clinic and mass media, promotion of Korean medicine therapies for osteoporosis, management of clinical trial participants, and insurance coverage for Korean medicine.

Nd : YAG layer 조사가 치근면의 미세경도에 미치는 영향

안재현,김병옥,한경윤,Ahn, Jae-Hyeun,Kim, Byung-Ok,Han, Kyung-Yoon 대한치주과학회 1995 Journal of Periodontal & Implant Science Vol.25 No.3

Root caries is very frequently developed on exposed root surface after periodontal surgical treatment. In order to determine the anti-caries effect of Nd : YAG laser irradiation on periodontally exposed root surface, 40 mandibular molar teeth that had been extracted due to excessive periodontal destruction were used as the experimental teeth. All teeth were treated by the same procedure as conventional periodontal root treatment, ie thorough scaling, root planing and root conditioning with tetracycline HCl(100mg/ml, 5min.). Within middle one third of root, mesial half surface(20) or distal half surface(20) was randomly irradiated at various power of 1.0W, 2.0W, 3.0W and 4.0W for 60 seconds by non-contact(5mm) delivery of a pulsed Nd : YAG laser(EN.EL.EN060, Italy). The microhardness was measured by Vikers microhardness tester(Wilson, USA) at 2mm/second of jog speed under 100gm load. The difference of microhardness between irradiated side and non-irradiated side was statistically analyzed ANOVA and Duncan's method. Following results were obtained ; 1. The microhardness(Knoop hardness number) was significantly higher in laser irradiated surface than non-irradiated surface(p<0.05). 2. There was no significant difference in microhardness between experimental groups classified by different laser power(p>0.1). The results suggest that Nd : YAG laser irradiation on exposed root suface after periodontal therapy may inhibit the root caries development by enhancing surface microhardness.

초기 골 접촉이 없는 순수 티타늄 임프란트 주위 골의 치유반응

안재현,김흥중,박주철,한경윤,김병옥,Ahn, Jae-Hyun,Kim, Heung-Joong,Park, Joo-Cheol,Han, Kyung-Yoon,Kim, Byung-Ock 대한치주과학회 1999 Journal of Periodontal & Implant Science Vol.29 No.1

Primary fixation is one of the most important factor in establishing adequate osseointegration between implant and bone. To evaluate the initial healing response of bone around implants without primary bone contact, this study was designed to create considerable space between implant and bone in 5 mongrel dogs, about 1-year old. After 3 holes of 6.0mm in diameter were prepared at the femur neck of the dogs, commercially pure titanium thread type implants(STERI-$OSS^{(R)}$), 8mm in length and 3.8mm, 5.0mm and 6.0mm in diameter, were inserted. Implants were supported by only nonresorbable membrane($Teflon^{(R)}$), and the penetration of upper soft tissue into the gap was inhibited by it. The each implant was positioned in the center of the drilled hole. 9 implants with different diameters were inserted in 3 dogs for histologic observation, and 12 were inserted in 2 dogs for mobility test and removal torque test.Fluorescent dyes were injected in order of Doxycycline, Alizarin Red S, and Calcein at intervals of 2 weeks. At 4-, 8-, and 12-week after placement, 3 dogs were sacrificed for histologic observation, and at 8- and 12-week after placement, 2 dogs were sacrificed for mobility test using $Periotest^{(R)}$ (Simens AG, Bensheim, Germany) and torque test using Autograph AGS-1000D $series^{(R)}$(Japan). The result were as follows: 1. The wider the gap between bone and implant was, the less bone maturity was, and the later osseointegration was occurred. Trabecular direction of new bone around implant was changed from parallel to perpendicular to the implant, and the gap was filled with new bone, over time. 2. There was a decreasing tendency over time in the mobility of all implants, but the wider gap between bone and implant was, the smaller decrease of the mobility was. 3. There was a increasing tendency over time in the removal torque gauge of all implants, and the wider gap was, the smaller increase of the removal torque gauge was. The results suggest that osseointegration in case of implant without primary bone contact may be obtained by guided bone regeneration technique with prolonged healing period, but the time of second surgery should be considered carefully.

인터넷 배너 광고의 시각적 자극 특성이 시각적 주의와 기억에 미치는 영향

안재현(Jae Hyeon Ahn),변준영(Joon Young Byun),이주원(Joo Won Lee),한상필(Sang Pil Han) 한국마케팅학회 2009 마케팅연구 Vol.24 No.4

인터넷 배너 광고는 2000년대 들어 클릭율이 0.2% 대로 추락하면서 그 효과성에 의문이 제기되었다. 그러나 소비자가 인터넷 광고를 클릭하지 않아도 단순히 노출된 것만으로 소비자의 브랜드 선호도가 영향을 받는다는 사실이 알려짐에 따라, 광고 노출 정도 및 효과에 대한 재평가의 필요성이 제기되었다. 특히 컴퓨터 화면의 극히 일부만을 차지하는 인터넷 배너 광고의 경우에는 광고 노출 정도에 대한 정확한 평가를 위해 실제 시각적 주의를 측정하는 것이 중요하다. 본 연구는 아이트래커를 이용한 실험을 통하여 사용자의 실제 시각적 주의를 측정한 후에, 광고의 시각적 특성 및 인터넷 사용자의 사용 정황이 시각적 주의를 끄는데 어떤 영향을 주는지, 그리고 시각적 주의가 재인 및 회상에는 어떤 영향을 미치는지를 분석하고 그 의미를 도출하였다. 분석 결과, 인터넷 배너 광고의 시각적 자극(애니메이션과 색상)은 과제 수행 여부에 따라 시각적 주의에 상이한 영향을 주는데, 수행 과제가 없는 경우에는 지나치게 화려하거나 단순한 광고보다는 적당한 정도로 화려한 광고가 시각적 주의를 가장 많이 끌었고, 수행 과제가 있는 경우에는 광고의 시각적 자극의 정도가 시각적 주의에 영향을 주지 않았다. 과제수행 여부와 시각적 자극의 복잡성이 시각적 주의와 기억의 관계를 조절하는 영향을 분석한 결과, 수행할 과제가 있거나 광고 자체를 해석하기 위해 자원이 많이 소요되는 화려한 광고에 노출된 경우에는 인지적 과부하가 일어나 시각적 주의가 있었음에도 불구하고 재인 및 회상이 일어나지 않았다. 본 논문에서 실증적으로 확인된 이러한 사실들은 향후 효과적인 인터넷 광고 전략 수립 및 가격 모델 구축 시에 반영되어야 할 것으로 보인다. Internet advertising has continued to expand rapidly. This explosion in Internet advertising was caused by the increasing use of the Internet as a new medium. Today Internet is a daily part of the lives of most people. According to TNS Global, Korean adults spend more than 40% of their leisure time on the Internet. While surfing the Internet, users are confronted with not one but a number of Internet ads on most web pages. Moreover, most Internet ads are equipped with various attention-grabbing devices such as animation, colorful pictures, bigger size characters, and this leads to competitive clutter on websites. Unlike the typical advertisement exposure on TV, people intentionally avoid Internet banner ads on computer screens, which share the space with many other editorial contents. In order to assess the impact of the Internet banner ads, it is important to examine whether or not users are actually looking at the Internet banner ads and if they do, how long they pay attention to the ads. In this paper, people`s actual eye movements are measured and analyzed with the help of a modern eye-tracking device. According to the motion effect theory and distinctiveness theory, people have a tendency to pay instant attention to moving objects or distinctive things that stands out from the environment. Animation and color are popular visual characteristics used for attracting Internet users` attention in the banner ads. However, people need to consume more cognitive resources when they process such animated and colorful objects compared to when they process static and black-and-white objects. Therefore, the excessive use of animation and color in banner ads can have adverse effects on visual attention and on memory. Thus it remains an empirical question to test whether the animated and colorful banner ads attract more attention and improve memory. Another dimension for user attention allocation could be the complexity of the task. Some users may be seeking for specific information on the Internet at work, while others may be browsing the web aimlessly in their leisure time. Whether they have a specific task to perform or not, it may influence the amount of visual attention paid to banner ads and also the process of encoding and storing information from the banner ads. Therefore, by measuring user eye movement data, we first investigate the effect of the visual characteristics (animation and color) of banner ads and the complexity of user task on visual attention. Then, we analyze the effect of visual attention to memory with available cognitive resource as a moderator. For empirical analysis, 104 participants were randomly assigned to either a specific task group or an undefined task (i.e. browsing) group and they were exposed to a portal site, where banner ads were embedded, for approximately three minutes. While they were participating in the experiment, their eye movement data was automatically collected by the Tobii T120 eye-tracker. After experimentation, they were asked to fill out survey questions for recognition and recall as well as a demographic profile. The analysis results show that first, the effect of visual characteristics (animation and color) on visual attention depends on whether they have a specific task or not. Without a specific task to perform, moderately complex ads (colorful ads without animation) caught more visual attention than either extremely complex ads (animated ads) or simple ads (black-and-white ads without animation). On the other hand, with a specific task to perform, visual characteristics of the banner ads had no significant effect on visual attention. Second, the moderating role of task and complexity of visual characteristics was found. For example, when users have a specific task or they are exposed to extremely complex ads, visual attention was not directly translated into memory (recognition and recall) improvement. Those results are consistent with the limited capacity model of mediated messa