한반도 대운하-인간과 자연, 일터와 쉼터가 어우러지는 21세기 다목적 프로젝트

박승환,Park, Seung-Hwan 한국기술사회 2008 技術士 Vol.41 No.2

The construction of korea grand canal supplys nation as below:$\Delta$ return to clean and clear river $\Delta$ offer urbanite space for re-charging $\Delta$ offer local resident tourist attractions $\Delta$ alternative for global warming $\Delta$ economic project for development and growth $\Delta$ awake sleeping inland city $\Delta$ strengthen business competitiveness $\Delta$ reduction of logistic cost

IoT 기반 화재탐지시스템의 연기 및 온도감지기 비화재보 신호 패턴 분석

박승환,김두현,김성철,Park, Seunghwan,Kim, Doo-Hyun,Kim, Sung-Chul 한국안전학회 2022 한국안전학회지 Vol.37 No.2

Fire-alarm systems are safety equipment that facilitate rapid evacuation and early suppression in case of fire. It is highly desirable that fire-alarm systems have low false-alarm rates and are thus reliable. Until now, researchers have attempted to improve detector performance by applying new technologies such as IoT. To this end, IoT-based fire-detection systems have been developed. However, due to scarcity of large-scale operational data, researchers have barely studied malfunctioning in fire-alarm systems or attempted to reduce false-alarm rates in these systems. In this study, we analyzed false-alarm rates of smoke/temperature detectors and unwanted fire-alarm signal patterns at K institution, where Korea's largest IoT-based fire-detection system operates. After analyzing the fire alarm occurrences at the institution for five years, we inferred that the IoT-based fire-detection system showed lower false-alarm rates compared to the automatic fire-detection equipment. We analyzed the detection pattern by dividing it into two parts: normal operation and unwanted fire alarms. When a specific signal pattern was filtered out, the false-alarm rate was reduced to 66.9% in the smoke detector and to 46.9% in the temperature detector.

Wireless LAN 환경에서 임베디드 SIP User Agent 구현

박승환,이재흥,Park Seung-Hwan,Lee Jae-Heung 한국정보통신학회 2005 한국정보통신학회논문지 Vol.9 No.3

본 논문은 무선의 임베디드 시스템 환경에서, VoIP 시스템을 구성하는 프로토콜 요소 중의 하나인 SIP를 이용한 User Agent의 구현에 관한 연구이다. User Agent는 설정 블록과, 주변 장치를 제어하기 위한 디바이스 쓰래드 블록, SIP 메시지를 처리하기 위한 SIP 스택 블록으로 구성하였다. 디바이스 쓰래드는 RTP 쓰래드 블록과 사운드 카드 처리 블록으로 구성하였으며, SIP 스택은 프락시 이벤트를 처리하는 워커 쓰래드 블록과 SIP 메시지를 전송하여 처리하는 SIP 트랜시버 및 SIP 쓰래드 블록으로 구성하였다. 하드웨어 플랫폼은 Intel XScale PXA25S 프로세서 기반에 플래쉬 메모리, SDRAM, AC'97 오디오 코덱, 무선 랜카드와 연결된 PCMCIA 소켓이 내장된 보드를 구성하였으며, 오디오 입출력으로 마이크로폰과 헤드폰을 사용하였다. 본 연구의 실험을 위한 타겟 시스템 구성은 임베디드 리눅스 커널 2.4.19를 포팅하였다. 임베디드 시스템의 자원 효율을 높이고자, User Agent의 속성과 SIP 메소드의 기능을 최소화하였고, TCP를 배제하여, 주변 장치 제어를 최소화함으로써, 자원의 소비를 $12.9\%$ 절감할 수 있었다. This paper is about the research of the User Agent implementation under wireless embedded environment, using SIP which is one of protocol components construct the VoIP system. The User Agent is made of the User Agent configuration block, the device thread block to control devices and the SIP stack block to process SIP messages. The device thread consists of the RTP thread and the sound lard device processing block. Futhermore, the SIP stack consist of the worker thread to process proxy events, the SIP transceiver and SIP thread to transfer and receive SIP messages. The H/W platform is a board included the Intel's XScale PXA255 processor, flash memory, SDRAM, Audio CODEC module and wireless LAN threough PCMCIA socket, furthermore a microphone and headphone is used by the audio 1/0. The system has embedded linux kernel 2.4.19. For embedded environment, the function of User Agent and SIP method is diminished. Finally, the resource of system could be reduced about $12.9\%$, compared to overall system resource, by minimizing peripherals control and excepting TCP.

Optical Properties of Green InGaN/GaN Quantum-Wel Light-Emitting Diodes with Embedded AlGaN Layer

박승환,Yong-Tak Lee,Jongwoon Park 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.1

The optical characteristics of green InGaN/GaN double-quantum-well (QW) structures with embedded AlGaN layers are investigated using the multiband effective mass theory. These results are compared with those of single QW structure without a layer. A double QW structure has a much larger spontaneous emission than a single QW structure for a relatively thick well width (Lw= 5 nm) because a double QW structure has a larger optical matrix element and a smaller effecive well width than a single QW structure. The inclusion effect of a layer is found to be dominant at a relatively thick well width. However, the double QW structure is shown to need a slightly larger In composition to obtain the same transition wavelength as the single QW structure.

여성전문병원 병동부의 거주성 향상을 위한 건축 계획적 연구

박승환,홍성우,최무혁,Park, Seung-Hwan,Hong, Sung-Woo,Choi, Moo-Hyuck 한국주거학회 2007 한국주거학회 논문집 Vol.18 No.2

The purpose of this study was to provide the basic data for architectural planning through survey about the ward of women's hospital. This study considered the concept of women's hospital through theoretical consideration and analysed a blueprint of 30 cases about typical plan type, the size and layout of patient-room, space allocation and circulation. And then a survey of patients has to identify their needs. Because the rate of composition of an upper grade patient-room in women's hospital is higher than that of general hospital to improve habitability in ward needs not only the importance of the planing of patient-room itself, but also providing a small courtyard, day-room between the patient-rooms or outdoor terrace. When patient moves it was provided visual comfort and strengthen social exchange. Also, physical environment has to reflect mother's psychological needs and diversity by individuality in unit is essential to planning.

사례 분석을 통한 IoT 기반 화재탐지시스템의 화재 감지신호 특성

박승환,김두현,김성철,Park, Seung Hwan,Kim, Doo Hyun,Kim, Sung Chul 한국안전학회 2022 한국안전학회지 Vol.37 No.3

This study aims to provide a fundamental material for identifying fire and no-fire signals using the detection signal characteristics of IoT-based fire-detection systems. Unlike analog automatic fire-detection equipment, IoT-based fire-detection systems employ wireless digital communication and are connected to a server. If a detection signal exceeds a threshold value, the measured values are saved to a server within seconds. This study was conducted with the detection data saved from seven fire accidents that took place in traditional markets from 2020 to 2021, in addition to 233 fire alarm data that have been saved in the K institute from 2016 to 2020. The saved values demonstrated variable and continuous VC-Signals. Additionally, we discovered that the detection signals of two fire accidents in the K institution had a VC-Signal. In the 233 fire alarms that took place over the span of 5 years, 31% of smoke alarms and 30% of temperature alarms demonstrated a VC-Signal. Therefore, if we selectively recognize VC-Signals as fire signals, we can reduce about 70% of false alarms.

Effects of Crystal Orientation on the Optical Gain Characteristics of Blue AlInGaN/InGaN Quantum-well Structures

박승환,최용희,Mun-Bo Shim,김성진,Chang Young Park,Y. Eugene Pak,다네시와미시라,유승현,강건욱 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.4

The effects of crystal orientation on the optical gain characteristics of blue AlInGaN/InGaNquantum-well (QW) structures with a reduced internal field were investigated by using the non-Markovian model with many-body effects. The AlInGaN/InGaN system has a larger matrix elementthan the conventional InGaN/GaN system because the former has a smaller internal field than thelatter for relatively small crystal angles. As a result, for QW structures with a relatively smallcrystal angle ( = 30), the AlInGaN/InGaN system is shown to have a much larger optical gainthan the conventional InGaN/GaN system. On the other hand, in the case of QW structures witha large crystal angle ( = 90), the AlInGaN/InGaN system is shown to have a smaller optical gainthan the conventional InGaN/GaN system. Hence, we expect that we can obtain high-efficiencyoptoelectronic devices by using quaternary AlInGaN QW for relatively small crystal angles.

광통신용 GaAs 기반 1.3 μm GaAsSb/InGaAs와 GaAsSb/InGaNAs 양자우물 레이저의 광학적특성 시뮬레이션

박승환,Park, Seoung-Hwan 한국전기전자재료학회 2011 전기전자재료학회논문지 Vol.24 No.1

Optical gain characteristics of $1.3{\mu}m$ type-II GaAsSb/InGaNAs/GaAs trilayer quantum well structures were studied using multi-band effective mass theory. The results were compared with those of $1.3{\mu}m$ GaAsSb/InGaNAs/GaAs trilayer quantum well structures. In the case of $1.3{\mu}m$ GaAsSb/InGaNAs/GaAs trilayer quantum well structure, the energy difference between the first two subbands in the valence band is smaller than that of $1.3{\mu}m$ GaAsSb/InGaNAs/GaAs trilayer quantum well structure. Also, $1.3{\mu}m$ GaAsSb/InGaNAs/GaAs trilayer quantum well structure shows larger optical gain than $1.3{\mu}m$ GaAsSb/InGaNAs/GaAs trilayer quantum well structure. This means that GaAsSb/InGaNAs/GaAs system is promising as long-wavelength optoelectronic devices for optical communication.

도심지내 분수유형별 음이온 분포 및 상관성 분석

김정호 ( Jeong Ho Kim ),박승환 ( Seung Hwan Park1 ),김원태 ( Won Tae Kim ),윤용한 ( Yong Han Yoon ) 한국환경과학회 2013 한국환경과학회지 Vol.22 No.12

In order to verify the healing effect in the variety of effects according to fountain type, anion which is the representatives factor of healing, as the center of case studies which in Gwanghwamun(Ground fountain), Cheonggyecheon(Waterfall) and Myeongdong(Formative fountain). According to fountain type, the anion distribution as follow, figures typically 15,721 ± 419 ea/cm³, Formative fountain 40,190 ± 788 ea/cm³, Waterfall 4,480 ± 290 ea/cm³ and ground fountain 2,492 ± 180 ea/cm³. It is usually exceed to the distribution in natural green, which is 1070∼2100 ea/cm³. The interrelation between air temperature, relative humidity, wind speed and relative humidity, and wind speed is that, the relative humidity is directly proportional to wind speed and inversely proportional to temperature. As the temperature goes up, the distribution of anion goes down. And as the wind speed and relative humidity goes up, the distribution of anion decrease sharply. The result of interrelation between fountain type and the anion distribution is that, the distance of water falling is directly proportional to the anion distribution in the formative fountain and inversely proportional in the ground fountain. And the distribution of anion is largest in formative fountain. The distribution of anion in ground fountain is lower than in formative fountain, but it is far more than in natural greenery. And as the distance from fountain increase, the distribution of anion goes down.

대규모 행사 이후 교통정체 해소방안 - 계룡대 장교 합동임관식 사례를 중심으로 -

장선기,박승환,정경원,Jang, Sun-Ki,Park, Seung-Hwan,Jeong, Kyung-Won 한국시뮬레이션학회 2017 한국시뮬레이션학회 논문지 Vol.26 No.3

본 연구는 대규모 행사 이후 발생하는 교통정체 문제를 계룡대 장교 합동임관식 행사를 중심으로 다루었으며, 문헌조사와 Arena를 활용한 분석을 통해 교통정체를 해소할 수 있는 개선방안을 제시하였다. 연구대상 행사는 매년 7,400여 대의 차량이 한정된 주차장과 도로로 유입되고, 행사 후에 동시 집중적으로 출차함에 따라 극심한 정체현상이 발생되고 있다. 이 문제를 해결하기 위해 주차장을 가용한 범위에서 분산 운용하고, 집중되는 차량 진출방향과 노선을 분산시키는 대안을 제시하였다. 그 결과 교통정체 시간이 150분에서 64분으로 86분 단축되었으며, 2017년 행사에 준용하여 교통정체 해소에 기여하였다. This study focuses on resolving traffic congestion caused by a large scale event based on the case of ROK Joint Officer Commissioning Ceremony, and it was conducted through literature review as well as Arena Simulation. The study purpose is to appropriately allocate and disperse the traffic by utilizing nearby parking lots of facilities. The annual event draws about 7,400 vehicles to a limited number of parking lots, and all vehicles leave the parking lots concurrently, causing a severe bottleneck near the exit and a few roads. In order to resolve the issue, the optimal number of cars in the event area was analyzed. After the analysis, the study found that the overflow of cars in the event area should be allocated to nearby parking lots of facilities with shuttle buses operating to transport the attendees. As the proposed result of the simulation, the traffic congestion time was reduced from 150 minutes to 64 minutes, a total reduction of 86 minutes.