• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2003년도 제27회 추계학술대회
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• pp.64-64
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• 2003

Objectives: Patient dose verification is clinically the most important parts in the treatment delivery of radiation therapy. The three dimensional(3D) reconstruction of dose distribution delivered to target volume helps to verify patient dose and determine the physical characteristics of beams used in intensity modulated radiation therapy(IMRT). We present Beam Intensity Scanner(BInS) system for the pre treatment dosimetric verification of two dimensional photon intensity. The BInS is a radiation detector with a custom made software for relative dose conversion of fluorescence signals from scintillator. Methods: This scintillator is fabricated by phosphor Gadolinium Oxysulphide and is used to produce fluorescence from the irradiation of 6MV photons on a Varian Clinac 21EX. The digitized fluoroscopic signals obtained by digital video camera will be processed by our custom made software to reproduce 3D relative dose distribution. For the intensity modulated beam(IMB), the BInS calculates absorbed dose in absolute beam fluence, which are used for the patient dose distribution. Results: Using BInS, we performed various measurements related to IMRT and found the followings: (1) The 3D dose profiles of the IMBs measured by the BInS demonstrate good agreement with radiographic film, pin type ionization chamber and Monte Carlo simulation. (2) The delivered beam intensity is altered by the mechanical and dosimetric properties of the collimating of dynamic and/or static MLC system. This is mostly due to leaf transmission, leaf penumbra, scattered photons from the round edges of leaves, and geometry of leaf. (3) The delivered dose depends on the operational detail of how to make multileaf opening. Conclusions: These phenomena result in a fluence distribution that can be substantially different from the initial and calculative intensity modulation and therefore, should be taken into account by the treatment planing for accurate dose calculations delivered to the target volume in IMRT.

• International Journal of Computer Science & Network Security
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• 제23권6호
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• pp.147-154
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• 2023

Network intrusion refers to any unauthorized penetration or activity on a computer network. This upsets the confidentiality, integrity, and availability of the network system. One of the major threats to any system's availability is a Denial-of-Service (DoS) attack, which is intended to deny a legitimate user access to resources. Therefore, due to the complexity of DoS attacks, it is increasingly important to abstract and describe these attacks in a way that will be effectively detected. The automaton theory is used in this paper to implement a SYN Flood detection system based on Time-Dependent Finite Automata (TDFA).

• Journal of Biosystems Engineering
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• 제30권3호
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• pp.155-160
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• 2005

The objective of this research was to establish a domestically available cooling storage technique by cold-air in winter, using winter cool air ventilation fur determining rough rice cooling method in the storage and dry bin. The rough rice storage characteristics of two test conditions, winter cool-air ventilation storage and ambient temperature storage, were evaluated from January to July 2001, using a storage and dry bin of 300-ton capacity. Results of this research are as follows: Grain temperature was from $-5.1\~-8.5^{\circ}C$ after winter cool-air ventilation, and grain initial temperature for ambient temperature bin storage was $0.3\~1.9^{\circ}C$. Moisture content of rough rice decreased from $0.28\;to\;0.93\%$ and from $1.53\;to\;1.92\%$ to compare with original moisture contents for winter cool-air ventilation, and for ambient temperature bin storage, respectively. Broken ratio of brown rice from winter cool-air ventilation bin increased from $0.16\;to\; 0.92\%$, and brown rice broken ratio was from $2.24\;to\;2.86\%$ for ambient temperature bin storage to compare with initial broken ratio. Hardness of stored rice increased along storage period increase in alt storage methods, and cooling bin storage increased rice hardness of 0.271kgf: this increasing was lower then the other methods from 0.059 to 2.239kgf. Germination rates were decreased approximately 9.03, 3.14 and $3.20\%$ for upper, middle, and bottom of ventilating winter air bin, respectively, and germination rates of 2.70, 3.47 and $4.14\%$ were approximately decreased for upper, middle, and bottom parts of ambient temperature bin storage, respectively.

• 한국의학물리학회지:의학물리
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• 제15권1호
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• pp.1-8
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• 2004

방사선 치료과정에서 가장 중요한 것은 환자에게 조사된 흡수선량을 검증하는 것이다. IMRT에 사용되는 방사선의 물리적 특성을 결정하고 환자에 조사된 선량분포를 검증할 수 있는 정밀한 선량 측정 장치가 필요하다. 본 연구에서 2차원 광자선의 선량검증을 위해 만들어진 BInS (Beam Intensity Scanner)에 관하여 논의한다. BInS에 있는 Scintillator는 광자선이나 전자선에 조사되면 형광을 발생하는 Gd$_2$O$_2$S:Tb를 주성분으로 한다. Scintillator에서 발생된 형광은 디지털 비디오카메라에 의해 수집되어 디지털 신호로 바뀌고 자체 제작한 소프트웨어에 의해 분석되며 상대적인 선량 분포가 3차원 그림으로 표시된다. BInS가 IMRT에서 사용가능한지를 알아보기 위하여 치료에 관련된 몇 가지 측정을 하였다. IMRT의 주요 작동방식 중의 하나인 SMLC (static multileaf collimator) 방식에서는, leaf들의 동작을 통제하여 만들어지는 여러 개의 정적 조사면적(static portal)을 통하여 IMB (intensity modulated beam)이 만들어진다. 따라서 여러 개의 정적 조사면적이 연달아 맞닿아 있는 경우, 연속된 두 조사면적의 경계면에서 penumbra와 산란된 광자들이 겹쳐지고 따라서 hot spot이 생기게 된다. 이와 같이 SMLC 방식에서 나타나는 inter-step hot spot들의 존재를 BInS를 이용하여 측정하여 가시화하였고 또한 그것들을 제거하는 실험적 방법도 제시하였다. IMRT에서 사용되는 다른 주요한 작동방식인 DMLC (dynamic multileaf collimator)는 광자선이나 전자선을 제어하는 leaf의 작동방식이 다르기 때문에 SMLC 방식과는 다른 특성을 보인다. 따라서 BInS를 이용하여 SMLC와 DMLC 방식에 의해 실제로 target에 투사된 선량을 측정 비교하였다. 비록 같은 선량을 target 부위에 투사하기로 계획했을지라도, 실제로는 산란된 광자와 전자들 때문에 DMLC 방식에 의한 선량이 SMLC 방식에 의한 선량보다 14.8%나 큰 것으로 측정되었다.

• 산업공학
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• 제17권1호
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• pp.1-12
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• 2004

In a modern semiconductor device manufacturing industry, statistical bin limits on wafer level test bin data are used for minimizing value added to defective product as well as protecting end customers from potential quality and reliability excursion. Most wafer level test bin data show skewed distributions. By Monte Carlo simulation, this paper evaluates methods and sample size effect regarding determination of statistical bin limits. In the simulation, it is assumed that wafer level test bin data follow the Poisson distribution. Hence, typical shapes of the data distribution can be specified in terms of the distribution's parameter. This study examines three different methods; 1) percentile based methodology; 2) data transformation; and 3) Poisson model fitting. The mean square error is adopted as a performance measure for each simulation scenario. Then, a case study is presented. Results show that the percentile and transformation based methods give more stable statistical bin limits associated with the real dataset. However, with highly skewed distributions, the transformation based method should be used with caution in determining statistical bin limits. When the data are well fitted to a certain probability distribution, the model fitting approach can be used in the determination. As for the sample size effect, the mean square error seems to reduce exponentially according to the sample size.

• 한국인터넷방송통신학회논문지
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• 제23권6호
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• pp.75-80
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• 2023

미래의 무선과 휴대용 계산 응용에서 DCT 대체할 수 있는 가역적인 블록 변환의 구현을 제시하였다. 이것을 binDCT라 불린다. BinDCT에서 정방향과 역방향 변환들은 이진 천이와 더하기 연산으로 구현될 수 있다. 그리고 binDCT는 바람직한 DCT 특징인(고코딩이득, DC손실 없음, 대칭적인 기저함수, 재귀적 구성)을 유지한다. 또한 binDCT는 lifting 특징인(빠른 구현, 가역적인 정수대정수 매핑, 내부 계산)을 유지한다. 따라서 복잡한 DCT 연산을 보다 빠르게 실행할 수 있는 장점을 가진다. 이 논문에서는 DCT와 binDCT의 계산비용과 성능분석을 Shapiro의 EZW을 사용하여 제시하였다.

• Journal of Biosystems Engineering
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• 제33권3호
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• pp.167-172
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• 2008

The objective of this study was to investigate the adequate storage method that was able to maintain the high quality of rough rice according to storage methods and period. The quality change of the rough rice during the storage period was evaluated by storage method such as cooling bin using winter cold air, ordinary temperature bin, freezing, refrigeration and indoor storage. Moisture content, brown rice whiteness, hardness, crack ratio and germination ratio were measured in this study. Moisture content of rough rice stored in cooling bin using winter cold air and ordinary temperature bin were decreased by 0.07% and 0.42%, respectively, which were lower than the other storage method. The hardness of brown rice increased in order of storage method such as winter cooling bin, normal bin, freezing storage, refrigeration storage and indoor storage. Crack ratio by indoor and ordinary temperature bin storage were increased by 2.68% and 3.63%, respectively, whereas cooling bin using winter cold air, refrigeration and freezing storage showed below 1.0%. The highest germination rate was found in cooling bin using winter cold air. As a result, cooling bin using winter cold air can be evaluated for the adequate storage method of rough rice.

• 인포메이션 디스플레이
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• 제19권2호
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• pp.24-31
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• 2018

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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• pp.1719-1722
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• 2003

Image enhancement를 하기 위한 영상처리 알고리즘 중의 하나인 contrast enhancement 알고리즘은 화면의 flickering 과 같은 부작용과 조절 가능한 contrast enhancement rate 에 대한 구현의 어려움 등으로 실제 TV와 같은 동영상에 적용하기에 어려움이 있었다. 본 논문에서는 Bin Underflow Bin Overflow(BUBO)를 이용하여 동영상에 적용할 경우에도 flickering 등의 부작용이 생기지 않으며 contrast enhancement rate 을 조절할 수 있는 효율적인 알고리즘을 제안한다. 또한 이와 관련하여 영상의 휘도 레벨에 있어서 어두운 영역의 계조와 밝은 영역의 계조를 향상시킬 수 있는 black/white level stretch 알고리즘과 전체 화면의 출력 휘도 레벨에 대한 dynamic range를 유지하면서 brightness를 조절할 수 있는 알고리즘을 제안한다.

• International Journal of Computer Science & Network Security
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• 제23권4호
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• pp.95-102
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• 2023

The emergence of Internet of Things (IoT) into our daily lives has grown rapidly. It's been integrated to our homes, cars, and cities, increasing the intelligence of devices involved in communications. Enormous amount of data is exchanged over smart devices through the internet, which raises security concerns in regards of privacy evasion. This paper is focused on the forensics and intrusion detection on one of the most common protocols in IoT environments, especially smart home environments, which is the Message Queuing Telemetry Transport (MQTT) protocol. The paper covers general IoT infrastructure, MQTT protocol and attacks conducted on it, and multiple network forensics frameworks in smart homes. Furthermore, a machine learning model is developed and tested to detect several types of attacks in an IoT network. A forensics tool (MQTTracker) is proposed to contribute to the investigation of MQTT protocol in order to provide a safer technological future in the warmth of people's homes. The MQTT-IOT-IDS2020 dataset is used to train the machine learning model. In addition, different attack detection algorithms are compared to ensure the suitable algorithm is chosen to perform accurate classification of attacks within MQTT traffic.