YACC을 이용한 속성문법 처리

전성욱(SungWook Jeon),김정훈(JungHoon Kim),장천현(ChunHyon Chang) 한국정보과학회 1994 한국정보과학회 학술발표논문집 Vol.21 No.1

CFG를 기본으로 한 LR파서인 YACC은 구문분석 도구로써 가장 널리 사용되어 왔다. 그러나 YACC은 자료의 하향전달이 어렵고 이를 처리하기 위해서는 많은 사용지식이 필요한 별도의 처리가 요구된다. 이를 자료 전달의 표현이 편리한 속성문법을 이용하여 자동적으로 처리할 수 있도록 하였다. 이와 같이 속성 문법의 적용은 사용자가 자료전달에 있어 하향이든 상향이든 관계없이 편리하게 표현하도록 한다. 그리고 이를 전달하는 처리는 모두 자동화하므로써 불필요한 오버헤드(over head)를 최대한 줄임으로써 컴파일러 작성의 효율을 높일 수 있다. 또 이런 자동화 처리를 YACC 전처리기에 형태로 만들어 이용하므로써 기존의 YACC을 그대로 사용할 수 있게 하였다.

Visualizations of combustion and fuel/air mixture formation processes in a single cylinder engine fueled with DME

Jeon, Joonho,Kwon, Sang Il,Park, Yong Hee,Oh, Yunjung,Park, Sungwook Elsevier 2014 APPLIED ENERGY Vol.113 No.-

<P><B>Abstract</B></P> <P>The purpose of this study is to investigate the effects of various engine conditions on the combustion, flame temperature and emission characteristics of dimethyl ether (DME) fuel compared with ultra-low sulfur diesel (ULSD) fuel through experimental and numerical analyzes. In order to analyze the temperature distribution, the KIVA-3V code and an optical HSDI diesel engine equipped with a visualization system were employed. The numerical validation was conducted with the experimental results from a DME-fueled compression ignition engine. In addition, measurement of the flame temperature from images captured during the combustion processes was performed using AVL-ThermoVision software.</P> <P>This investigation showed that the combustion pressure and heat release rate attained their peak value at the lowest engine speed condition for DME and ULSD fuels. The characteristics of the flame temperature value and distribution due to the differences in engine speed conditions and fuel properties were clearly revealed. When the engine speed increased, an inhomogeneous and low combustion temperature was observed. Furthermore, the nitrogen oxides (NO<I> <SUB>x</SUB> </I>) emissions, which are related to the combustion temperature, decreased as the engine speed increased.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Experimental and numerical approaches were used for DME combustion. </LI> <LI> DME fuel properties strongly affected temperature distribution. </LI> <LI> The differences of temperature distribution were showed under various conditions. </LI> <LI> DME combustion and emissions characteristics in comparison with ULSD fuel. </LI> </UL> </P>

Effect of injection pressure on soot formation/oxidation characteristics using a two-color photometric method in a compression-ignition engine fueled with biodiesel blend (B20)

Jeon, Joonho,Park, Sungwook Elsevier 2018 Applied thermal engineering Vol.131 No.-

<P><B>Abstract</B></P> <P>Biofuels are an alternative to petroleum fuels in transportation. Among various biofuels, biodiesel has been mixed with diesel fuel for use in compression ignition (CI) engines. Many countries legislate that standard diesel fuels contain a certain amount of biodiesel to reduce exhaust emissions. An increase in biodiesel content to a 20% volumetric ratio (B20) requires only minor modification to existing vehicle systems. Since discrepancies in fuel properties between B20 and conventional diesel fuel, much research has been performed on B20 combustion and emissions for the implementation of vehicles. The present study investigated spatial B20 combustion and soot emission processes in an optical CI engine under various injection pressure conditions. Volumetric 20% of soybean biodiesel added to diesel fuel and both blend fuel and conventional diesel fuel were used as test fuels. Apparent combustion and emissions were observed with respect to auto-ignition, brake power, and thermal efficiency. In addition, visualization system permitted a profound analysis of the spatial combustion flame and soot propagation. A two-color photometric method extracted quantitative soot density from the captured combustion images, which allowed to study the soot formation and oxidation processes. Although soot emissions decreased significantly out of the engine, the variations in the soot formation and oxidation processes in the combustion chamber were remarkable. Compared with neat diesel flame B20 fuel produced higher flame temperature over all injection pressure conditions. While B20 flame temperature was increased, soot emission of B20 fuel was exhausted with higher concentrations. Under a low load and high speed condition, B20 emissions revealed different results from those of general bio-blends with high thermal efficiency regardless of the injection pressure.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Spatial temperature and soot density in the combustion chamber using endoscope. </LI> <LI> Development of flame and soot emissions for 20% vol. biodiesel blend. </LI> <LI> Two-color photometric method evaluated temperature and soot intensity in images. </LI> <LI> Apparent combustion and emissions features in biodiesel blend and diesel fuels. </LI> </UL> </P>

Nitrogen Compounds (NO, NO₂, N₂O, and NH₃) in NO_<i>x</i> Emissions from Commercial EURO VI Type Heavy-Duty Diesel Engines with a Urea-Selective Catalytic Reduction System

Jeon, Joonho,Lee, Jong Tae,Park, Sungwook American Chemical Society 2016 ENERGY AND FUELS Vol.30 No.8

<P>Selective catalytic reduction (SCR) systems have been widely used in heavy-duty (HD) diesel engines to meet the stringent emission standards for nitrogen oxides. The mobile SCR system has improved the considerable reduction of NOx emission from HD diesel engines. Many investigations have been performed to enhance the catalytic performance and optimize the SCR system within the diesel engines. The purpose of the present study was to investigate the types of nitrogen components (NO, NO2, N2O, and NH3) in the NOx exhaust emissions prior to and after passing through an SCR device. A EURO VI type commercial heavy-duty diesel engine was equipped to an AC dynamometer. World harmonized stationary cycle and transient cycle were introduced to operate the test engine under road conditions. A new quantum cascade laser analyzer was employed to measure the nitrogen emission species in real time. The engine-out NOx emissions were strongly affected by the load conditions of the engine, which also determined the efficiency of SCR conversion. Total conversion rates of up to 96% were achieved for both test modes. Various concentrations of urea were used as a reducing agent in the SCR system. On the basis of the urea concentration, the conversion efficiency and composition of nitrogen oxides varied under the same engine conditions. The fraction of nitrogen compounds in NOx emissions changed during the catalytic processes within the SCR system. The results yielded accurate concentration values for nitrogen compounds in the commercial heavy-duty engine, warning of the possibility of a new greenhouse gas due to converted NOx emissions.</P>

Decline of Serum Anti-Mullerian Hormone level after Laparoscopic Ovarian Cystectomy is similar between Patients with Endometrioma and those with Mature Cystic Teratoma

( Sungwook Chun ),( Gyun Ho Jeon ),( Hyun Jin Cho ),( Yong Il Ji ) 대한산부인과학회 2014 대한산부인과학회 학술대회 Vol.100 No.-

목적: The aim of this study was to evaluate the difference of the change of ovarian reserve after unilateral laparoscopic ovarian cystectomy (LOC) in early postoperative period between patients with endometrioma and those with mature cystic teratoma. 방법: Sixty-five patients who received scheduled unilateral LOC for benign ovarian disease were participated in this study. All participants were divided into three groups according to pathologic diagnosis after LOC: 26 patients diagnosed as ovarian endometrioma were included in group 1, 24 patients with mature cystic teratoma in group 2, and 15 patients with other benign cyst in group 3. Preoperative and postoperative day 3 serum samples were collected and assayed for anti-Mullerian hormone (AMH) levels, and the changes between the two samples were analyzed. The rate of decline of AMH levels was calculated by [(preoperative AMH level ? postoperative day 3 AMH level)/ (preoperative AMH level)] × 100 (%). 결과: Mean age in patients with endometrioma was significantly higher than those in the other two groups. Preoperative AMH levels were not significantly different between three groups. Postoperative day 3 AMH levels were significantly reduced compared to preoperative ones in all three groups. The rate of decline of AMH levels after LOC in patients with teratoma (28.25 ± 22.16%) was similar to that in those with endometrioma (26.37 ± 20.70%). The mean AMH decline in patients with other benign cyst (12.03 ± 18.56%) is lower compared to other two groups. AMH decline after LOC was not significantly correlated with age, body mass index, the size of ovarian cyst, or preoperative AMH levels. 결론: Our results suggest that the postoperative decline of AMH levels after LOC in early postoperative period is similar between patients with endometrioma and those with mature cystic teratoma.

Effect of the fuelling strategy on the combustion and emission characteristics of a gasoline–diesel dual-fuel engine

Jeon, Joonho,Lee, Seokhwon,Park, Sungwook Professional Engineering Publishing Ltd 2017 Proceedings of the Institution of Mechanical Engin Vol. No.

신경 신호 측정을 위한 마이크로 모터 기반 마이크로 드라이브

양성욱(Sungwook Yang),박기태(Kitae Park),전효진(Hyojin Jeon),조제원(Jeiwon Cho),신희섭(Hee-Sup Shin),윤의성(Eui-Sung Yoon) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

The miniature motorized microdrive which is applicable to the neural signal recording in gene-modifiable mice is presented. The microdrive is manipulated with direct driving method of micro motor within the range of 2.8㎜, with the resolution of 0.742 ㎜. A moving electrode in a mouse brain is monitored with an integrated MR(Magneto-Resistive) sensor. This microdrive, which is trapezoidal, has the length of 7.1㎜, the width of 5㎜, the height of 22.5 ㎜ and the weight of 1.45g only. The displacement of the microdrive was evaluated and verified in the range of 1000 ㎛. The neural signal of the mouse in anesthesia was recorded successively with the microdrive moving.

Light-Induced Fluorescence Modulation of Quantum Dot-Crystal Violet Conjugates: Stochastic Off–On–Off Cycles for Multicolor Patterning and Super-Resolution

Jung, Sungwook,Park, Joonhyuck,Bang, Jiwon,Kim, Jae-Yeol,Kim, Cheolhee,Jeon, Yongmoon,Lee, Seung Hwan,Jin, Ho,Choi, Sukyung,Kim, Bomi,Lee, Woo Jin,Pack, Chan-Gi,Lee, Jong-Bong,Lee, Nam Ki,Kim, Sungjee American Chemical Society 2017 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.139 No.22

<P>Photoswitching or modulation of quantum dots (QDs) can be promising for many fields that include display, memory, and super-resolution imaging. However, such modulations have mostly relied on photomodulations of conjugated molecules in QD vicinity, which typically require high power of high energy photons at UV. We report a visible light-induced facile modulation route for QD-dye conjugates. QD crystal violets conjugates (QD-CVs) were prepared and the crystal violet (CV) molecules on QD quenched the fluorescence efficiently. The fluorescence of QD-CVs showed a single cycle of emission burst as they go through three stages of (i) initially quenched off to (ii) photoactivated on as the result of chemical change of CVs induced by photoelectrons from QD and (iii) back to photodarkened off by radical-associated reactions. Multicolor on-demand photopatterning was demonstrated using QD-CV solid films. QD-CVs were introduced into cells, and excitation with visible light yielded photomodulation from off to on and off by nearly ten fold. Individual photoluminescence dynamics of QD-CVs was investigated using fluorescence correlation spectroscopy and single QD emission analysis, which revealed temporally stochastic photoactivations and photodarkenings. Exploiting the stochastic fluorescence burst of QD-CVs, simultaneous multicolor super-resolution localizations were demonstrated.</P>

자궁절제술이 수술 초기 난소예비력에 미치는 영향

전성욱 ( Sungwook Chun ),전균호 ( Gyun Ho Jeon ),조현진 ( Hyun Jin Cho ),지용일 ( Yong Il Ji ) 대한산부인과학회 2012 Obstetrics & Gynecology Science Vol.55 No.1

Objective The aim of this study was to evaluate the changes of the ovarian reserve in early postoperative period after hysterectomy in Korean women. Methods We retrospectively reviewed the medical records and laboratory data of patients aged 30-50 years with regular menstruation before hysterectomy, and 31 patients were included in this study. All patients enrolled underwent scheduled hysterectomy with conservation of both ovaries (laparoscopy-assisted vaginal hysterectomy, n=21; and total abdominal hysterectomy, n=10), and received serum anti-Mullerian hormone (AMH) tests preoperatively and 3 days after operation. Changes between preoperative and postoperative AMH levels of each patient were calculated. Results There were no signifi cant differences between pre-and postoperative AMH concentration (2.46±0.49 ng/mL and 2.29±0.43 ng/ mL; P=0.200). No signifi cant percentage reduction of AMH level existed (1.17±6.63%, P=0.861). Conclusion Our results suggest that hysterectomy does not infl uence the ovarian reserve in early postoperative period.

A Narrowband Active Noise Control System With Frequency Corrector

Hyeon-Jin Jeon,Tae-Gyu Chang,Sungwook Yu,Kuo, S M IEEE 2011 IEEE transactions on audio, speech, and language p Vol.19 No.4

<P>The performance of narrowband active noise control (ANC) systems degenerates significantly under the frequency mismatch between the synthesized reference signal and the primary noise. This paper proposes a new narrowband ANC system that incorporates a frequency corrector for the internal reference signal generator to mitigate the ill-effects caused by the frequency mismatch. The proposed frequency estimator uses the iterative frequency estimation algorithm based on the minimum variance distortionless response spectrum that has advantages of accuracy and fast convergence. The performance of the new narrowband ANC system is analyzed under the conditions of frequency mismatch and the secondary-path phase estimation error. The frequency and amplitude of the primary noise are modeled as time-varying variables in the theoretical analysis. Computer simulations are conducted to demonstrate the performance of the new ANC system and to verify the analysis results.</P>