Statistical Characteristics of Scattering Ratio Based on Three Optical Wavelengths for Smoke Particles

Kyuwon Han(Kyuwon Han),Soocheol Kim(Soocheol Kim),Hoesung Yang(Hoesung Yang),Kwang Soo Cho(Kwang Soo Cho),Kangbok Lee(Kangbok Lee),Ho-Sik Han(Ho-Sik Han) 한국화재소방학회 2022 International Journal of Fire Science and Engineer Vol.36 No.2

Photoelectric smoke detectors, which operate by reacting to the scattering of light caused by particles entering the light path, are widely used and extremely sensitive. Owing to higher standards imposed by Underwriters Laboratories, researchers have begun analyzing the properties of smoke particles. In particular, several wavelengths are used to classify particles by their scattering reactivity. The performances of actual smoke detectors are limited by their hardware and price. Therefore, properties that can distinguish particle types in these limited conditions must be determined. In addition, algorithms for extracting valid data intervals from unstable scattering data must be developed. In this study, scattering intensity ratios for three wavelengths are derived via simulations of light scattering by particles. An upper cumulative sum is defined for the three wavelengths, and an index for the start of particle inflow is extracted. In addition, valid intervals are extracted based on the scattering intensity ratios and the moving variance of adjacent wavelengths, and the properties of each particle are defined using the extracted indexes. For verification, a data acquisition device that can obtain data using the three selected wavelengths (470, 525, and 850 nm) from two sensors is designed. Five types of fire sources and non-fire alarm sources are selected and used in a test chamber designed to generate particle data. After applying the algorithm, the data in the valid data intervals can be used to derive a sample mean scattering intensity ratio that is more constant than that of the overall data or the data processed using the CUSUM index. In addition, the fire sources have a higher sample mean scattering intensity ratio than water vapor, which is a non-fire alarm source. The scattering intensity ratios for smoke particles can be extracted in real time via a comparison with experimental results obtained from the selected sensors.

Oral beclomethasone dipropionate as an add-on therapy and response prediction in Korean patients with ulcerative colitis

Kyuwon Kim,Hee Seung Hong,Kyunghwan Oh,Jae Yong Lee,Seung Wook Hong,Jin Hwa Park,Sung Wook Hwang,Dong-Hoon Yang,Jeong-Sik Byeon,Seung-Jae Myung,Suk-Kyun Yang,Byong Duk Ye,Sang Hyoung Park 대한내과학회 2022 The Korean Journal of Internal Medicine Vol.37 No.6

Background/Aims: We aimed to investigate the oral beclomethasone dipropionate’s (BDP) efficacy as an add-on therapy and to clarify the predictive factor for response to oral BDP in Korean ulcerative colitis (UC) patients. Methods: Patients with a stable concomitant drug regimen with exposure to oral BDP (5 mg/day) within 30 days before BDP initiation were included. Partial Mayo score (pMS) was used to evaluate response to oral BDP. Clinical remission (CREM) was defined as a post-treatment pMS ≤ 1 point. Clinical response (CRES) was defined as an at least 2-point decrease in post-treatment pMS and an at least 30% decrease from baseline pMS. Patients without CREM or CRES were considered nonresponders (NRs). Results: Of all, 37 showed CREM, 19 showed CRES, and 44 were NRs. The CREM group included more patients with mild disease activity (75.7% vs. 43.2%, p = 0.011) than NRs. In contrast to NRs, CREM and CRES patients showed significant improvement of post-treatment erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) (ESR with p = 0.001, CRP with p = 0.004, respectively). Moreover, the initial rectal bleeding subscore (RBS) was significantly different between CREM and CRES, or NR (both with p < 0.001). In multivariate analyses, initial stool frequency subscore (SFS) of 0 and RBS of 0 were predictive factors for CREM (odds ratio [OR], 15.359; 95% confidence interval [CI], 1.085 to 217.499; p = 0.043 for SFS, and OR, 11.434; 95% CI, 1.682 to 77.710; p = 0.013 for RBS). Conclusions: Oral BDP is an efficacious add-on therapy in Korean UC patients. Patients with initial SFS or RBS of 0 may be particularly good candidates for oral BDP.

Smoke Particle-Source Prediction Model Based on Multiple Optical Wavelengths Using Deep Learning

Yusun Ahn(Yusun Ahn),Kyuwon Han(Kyuwon Han),Hoesung Yang(Hoesung Yang),Soocheol Kim(Soocheol Kim),Jin Hwa Ryu(Jin Hwa Ryu),Kangbok Lee(Kangbok Lee) 한국화재소방학회 2023 International Journal of Fire Science and Engineer Vol.37 No.2

Recently, installing smoke detectors has become crucial owing to the risk of fatal human damage that may be caused by inhaling smoke during a fire. Smoke detectors have been reported as highly efficient in detecting smoke particles from fire; however, they may generate false alarms because of their limitation in distinguishing the fire smoke from the smoke generated by daily activities. Despite the frequent occurrence of these false alarms, research on predicting the types of sources through smoke particles remains insufficient. This study involved the development process of an intelligent smoke detector for false alarm reduction that aims to predict the occurrence and type of fire and the evaluation of its performance using the light-scattering characteristics for fire/non-fire sources. First, a previous experimental dataset of fire-related conditions was collected from three fire sources and three non-fire sources to train the model with the light-scattering characteristics of the smoke generated from each source. In addition, to reduce the computing power, data preprocessing was performed on the collected dataset using the median and RobustScaler. Finally, we evaluated the prediction performance of the three deep learning models using three networks: RNN, LSTM, and CNN-LSTM. As a result, we confirmed that the scattering intensity of smoke particles has unique characteristics for each source. When the data preprocessing and prediction models were applied, all three models achieved an accuracy of 0.90 or higher. However, some errors occurred that appeared at similar scattering intensities. The proposed method differs from existing methods in that it presents the possibility of predicting fire and non-fire sources and can be used as an alternative for improving false alarms in the future.

연기 입자 학습 DB 구축을 위한 지능형 화재 감지 시스템

한규원(Kyuwon Han),양회성(Hoesung Yang),이강복(Kang Bok Lee) 한국화재소방학회 2021 한국화재소방학회 학술대회 논문집 Vol.2021 No.추계

연기 감지기는 화재 감시를 위한 대표적인 소방기기로 광학을 이용한 광전식 감지기가 가장 대중화되어 있다. 입자의 크기에 따라 산란한 광의 세기를 파장 별로 분리하여 비화재보를 구분할 수 있으며 관련된 연구가 진행된 바 있다. 나아가 화원에 따라 발생하는 연기 입자의 분포가 상이하며 이를 광학 및 다양한 센서를 통해 구분하기 위해서 연기 입자에 대한 학습 DB 구축이 필요하다. 지능형 화재 감지 시스템은 센서 모듈과 중앙 처리 모듈, 그리고 연기 입자 학습 DB로 구성된다. 화재 입자에 대한 측정 데이터가 발생하는 센서 모듈이 다양화 되고 각기 다른 플랫폼을 기반으로 개발되어 각 장치에서 발생하는 데이터를 동시 수집 가능하고 정렬하여 데이터화 가능하도록 중앙 프로세서 모듈을 구조화하였다. 데이터 처리 에이전트는 화재 입자 표준 데이터를 정의하여 내부 DB를 운용하도록 동작하는 Internal DB / transform 프로세스와 데이터의 이상 감지와 학습 모델을 기반으로 분류를 수행하는 프로세스로 구성되어 있다. 동시에 사전 정의한 규칙에 따라 연기 입자 학습 DB로 누적 데이터를 전달하는 전송 에이전트가 동작한다. 한정된 자원 내 메모리 점유 최소화를 위하여 telegraf 기반으로 구현되었으며 각 프로세스 간 데이터 전달을 위하여 IPC를 통해 리소스를 공유하였다. 다수의 지능형 화재 감지 장비로부터 센싱 데이터와 화재 감지/분석정보를 수집하여 연기 입자 학습 DB를 구축하기 위하여 시계열 DB를 선정하여 구축하였다. 높은 수신 속도 및 데이터 압축을 위하여 InfluxDB 기반으로 구현하였으며 복수 개의 telegraf 에이전트와 동기화를 확인하였다. 또한 사용자를 위한 실시간 모니터링과 타 연구기관과의 협업을 위하여 해당 결과는 Grafana의 일부 툴킷을 활용하여 시각화하여 제공하였다. 연기 입자 학습 DB는 주기적으로 새로운 데이터를 기반으로 학습 모델을 갱신하며 갱신된 학습 모델은 중앙 처리 모듈로 배포된다. 본 논문에서 구현된 화재 감지 시스템은 2가지 폼 팩터의 소형 프로세서 보드에 적층 형태로 제작된 하드웨어에 각각 적용하였으며 실 화재 시험 장치에 투입하여 연기 입자 학습 DB와의 동기화 확인을 수행하였다.

Impact of Crohn’s Disease on the Survival of Patients with Small-Bowel Adenocarcinoma in Korea: A Bicenter Cohort Study

Kim Kyuwon,Choi Kookhwan,Hwang Sung Wook,Im Jong Pil,Ye Byong Duk,Kim Joo Sung,Park Kyu Joo,Yang Suk-Kyun,Koh Seong-Joon,Park Sang Hyoung 거트앤리버 소화기연관학회협의회 2023 Gut and Liver Vol.17 No.4

Background/Aims: Owing to the low prevalence of small-bowel adenocarcinoma (SBA), data on the impact of Crohn’s disease (CD) on the survival of patients with SBA are lacking. Therefore, we investigated this issue in this study. Methods: In this bicenter cohort study, patients with histologically confirmed SBA were retrospectively enrolled and classified into two groups: sporadic SBA and CD-associated SBA. Patients with duodenal SBA were excluded. Overall survival, disease-free survival, and factors associated with survival were analyzed. Results: Of 128 patients with SBA, 115 had sporadic SBA and 13 had CD-associated SBA. Ileal involvement and poorly differentiated tumors were more common in the CD-associated SBA group than in the sporadic SBA group (ileal involvement, 53.8% vs 22.6%; poor differentiation, 46.2% vs 14.8%; both p<0.05). In survival analysis, overall survival showed no statistical difference between the sporadic SBA and CD-associated SBA groups (p=0.370). However, when stratified by stage, the adjusted overall survival of the CD-associated SBA group was lower in patients with an advanced disease stage (p=0.029). Disease-free survival showed the same tendency, albeit without clinical significance (p=0.097). CD (hazard ratio [HR], 2.308; p=0.047), older age (≥65 yr) at SBA diagnosis (HR, 2.766; p=0.001), and stage III/IV disease (HR, 3.151; p<0.001) were factors associated with mortality. Conclusions: The overall survival of patients with CD-associated SBA did not differ from that of patients with sporadic SBA. However, as CD is an independent risk factor for mortality, vigilant surveillance in high-risk patients may be crucial.

다기종 P형 수신기 모니터링을 위한 IoT 디바이스 개발

한규원(Kyuwon Han),양회성(Hoe-Sung Yang),박소영(So Young Park),홍상기(Sang Gi Hong),이강복(Kang Bok Lee) 한국정보과학회 2019 한국정보과학회 학술발표논문집 Vol.2019 No.12

담론 논쟁의 동학(dynamics)으로 바라본 문화정책 73년

김규원(Kim,Kyuwon),지금종(Ji,Geumjong),염신규(Yum,Shinkyou),양혜원(Yang,Hye won) 한국문화관광연구원 2018 문화정책논총 Vol.32 No.2

Study of SU-8 to make a Ni master-mold: Adhesion, sidewall profile, and removal

Kim, Sung-Jin,Yang, Haesik,Kim, Kyuwon,Lim, Yong Taik,Pyo, Hyeon-Bong WILEY-VCH Verlag 2006 Electrophoresis Vol.27 No.16

<P>For disposable microfluidic devices, easy and inexpensive fabrication is essential. Consequently, replication of microfluidic devices, using injection molding or hot embossing, from a master-mold is widely used. However, the conventional master-mold fabrication technique is unsatisfactory in terms of time and costs. In this regard, direct Ni growth (electroplating) from a back plate is promising when the photoresist is well-defined. Here, we demonstrate the use of SU-8 as a photoresist to define the Ni-growth region. We accomplish this application by focusing on the adhesion, the sidewall profile, and the removal of SU-8: the adhesion is enhanced by controlling the exposure dose, the soft-baking time, and by choosing the adhesion-promoting layer; the sidewall profile is regulated by selecting the intensity of each exposed wavelength, showing an aspect ratio of up to 20.9; and, easy removal is achieved by choosing a proper photoresist-stripper. Using the master-mold fabricated by this method, we test the mechanical stability of the features according to the aspect ratio and length; in the hot embossing process, the features are stable in the aspect ratio of up to 5.8 at a length of 200 µm. In addition, the plastic devices fabricated from this method are applied to the passive stop valves, showing a capillary pressure (−0.2 to −7.2 kPa).</P>

Controlling the hydrophilicity of microchannels with bonding adhesives containing surfactants

Lim, Yong Taik,Kim, Sung-Jin,Yang, Haesik,Kim, Kyuwon IOP 2006 JOURNAL OF MICROMECHANICS AND MICROENGINEERING - Vol.16 No.7

<P>In this study, a novel protocol to control the hydrophilicity of microchannels as well as to bond the microfluidic devices in all polymer-based biomedical devices is suggested. It is demonstrated that the contact angle of water in the microchannel surface can be tuned using conventional pressure-sensitive adhesives (PSA) containing surfactants. The surfactants are immersed in a hydrophobic PSA film in hydrophobic environments (air). The water–adhesive interface reconstructed quickly and became hydrophilic upon contact with water. Both the contact angle and volumetric flow rate (VFR) of water in microchannels could be systematically controlled by changing the concentration of the surfactants in the PSA film and by using different types of surfactants with different chemical structures. The VFR of water changed in a two-order range (1–10<SUP>2</SUP> nl s<SUP>−1</SUP>) when the concentration of surfactants was varied from 1% to 10%. We believe that the use of surfactants favors mainly the control of flow rate and the protocol suggested here to control the flow velocity in a broad range should find a wide application. Although the hydrophilic coating formulated with surfactants has proven effective in improving the flow rate of liquid, the surfactants located at the interface could be dissolved into the fluid samples. And the beneficial result of the use of surfactants is restricted to microfluidic devices where the liquid stays briefly in contact with the channel walls. The protocol suggested in the research can be directly applied to the development of low-cost, high-speed and reliable bonding techniques for disposable polymer-based microfluidic devices.</P>

Passive regulation of volume-flow ratio for microfluidic streams with different hydrophilicity and viscosity

Kim, Sung-Jin,Lim, Yong Taik,Yang, Haesik,Kim, Kyuwon,Kim, Youn Tae WILEY-VCH Verlag 2010 Electrophoresis Vol.31 No.4

<P>Biochemical solutions have a wide range of hydrophilicity (contact angle and surface tension) and viscosity. A critical challenge is that microfluidic systems typically need expensive or complex pumps to control the various parallel biochemical streams. In this study, without using any pumps, we present a simple scheme that controls the ratio of the volumetric flow rate (VFR) of the parallel streams that have highly different hydrophilicity and viscosity. We accomplish this process by using capillarity to drive and merge two streams, and by regulating relative flow resistance to control the VFR ratio. Our results will significantly simplify the control of the VFR ratio for the various biochemical solutions that are used in microfluidic applications.</P>