• 제목/요약/키워드: 최정환

Search Result 160, Processing Time 0.021 seconds

Bayesian Optimization Framework for Improved Cross-Version Defect Prediction (향상된 교차 버전 결함 예측을 위한 베이지안 최적화 프레임워크)

  • Choi, Jeongwhan;Ryu, Duksan
    • KIPS Transactions on Software and Data Engineering
    • /
    • v.10 no.9
    • /
    • pp.339-348
    • /
    • 2021
  • In recent software defect prediction research, defect prediction between cross projects and cross-version projects are actively studied. Cross-version defect prediction studies assume WP(Within-Project) so far. However, in the CV(Cross-Version) environment, the previous work does not consider the distribution difference between project versions is important. In this study, we propose an automated Bayesian optimization framework that considers distribution differences between different versions. Through this, it automatically selects whether to perform transfer learning according to the difference in distribution. This framework is a technique that optimizes the distribution difference between versions, transfer learning, and hyper-parameters of the classifier. We confirmed that the method of automatically selecting whether to perform transfer learning based on the distribution difference is effective through experiments. Moreover, we can see that using our optimization framework is effective in improving performance and, as a result, can reduce software inspection effort. This is expected to support practical quality assurance activities for new version projects in a cross-version project environment.

Comparison of Bioactivities from Centella asiatica Cultivated in Smart Farm and Field (스마트팜과 노지에서 재배한 병풀의 생약학적 비교)

  • Jin Hong, Park;Da Hee, Lee;Seong Min, Jo;Jeong Hwan, Choi;Nam Jun, Kim;Min Su, Kim;Youngmin, Park;Kiman, Lee
    • Korean Journal of Pharmacognosy
    • /
    • v.53 no.4
    • /
    • pp.192-201
    • /
    • 2022
  • This study aimed to compare bioactivities of Centella asiatica (CA) cultivated in smart farms and fields. Component analysis, cell viability, anti-inflammatory activity, neuroprotection activity, and antioxidant activity were examined with 70% ethanol extracts of CA cultivated in smart farm (SEE) and field (FEE), respectively. Asiaticoside was analyzed by high performance liquid chromatography (HPLC) and as a result, SEE had more asiaticoside content than FEE. After treatment of RAW 264.7 cells with SEE and FEE, there was no cytotoxicity within the treated concentrations. SEE and FEE showed nitric oxide (NO), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 inhibitory activities in a dose-dependent manner in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Moreover, SEE inhibited more NO, TNF-α, and IL-6 production levels than FEE. SEE and FEE reversed the H2O2-induced SH-SY5Y cell death. Especially, SEE was more effective in changing the H2O2-induced SH-SY5Y cell death than FEE. The antioxidant activity was confirmed by various methods such as total phenol content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and superoxide dismutase (SOD). As a result, SEE showed the most potent antioxidant activities about TPC, DPPH, and SOD methods. This study suggested that SEE has higher bioactivities such as effect of anti-inflammation, neuroprotection, and antioxidation than FEE.

Volatile Substances and Physicochemical Characteristics of Pyroligneous Liquor (목초액의 휘발성 성분과 이화학적 특성)

  • Kim Jong-Soo;Park Seung-Woo;Choi Jung-Hwan;Lee Eun-Young;Lee Sang-Han;Chung Shin-Kyo
    • Food Science and Preservation
    • /
    • v.12 no.6
    • /
    • pp.656-661
    • /
    • 2005
  • To develop food additives from pyroligneous liquor, we first examined the physicochemical characteristics of volatile substances. The pH, gravity, acidity, solution tar, and scorched remains in the pyroligneous liquor were 2.50, 1.020, $0.8\%$ $2.31\%$ and $0.008\%$ respectively. The main compounds of pyroligneous liquor were 2,6-dimethoxyphenol (syringol), 2-hydroxy-2-cyclopenten-l-one, 1,2-benzenediol (catechol), phenol, 2 (5H)-furanone, 2-methoxyphenol (guaiacol), 5-hydroxymethyl-2 furancarboxaldehyde were found in organic phase, whereas catechol, 1,4 : 3,6-dianhydro-${\alpha}d$-glucopyranose, cyclopropyl carbinol, 5-hydroxymethyl-2 furancarboxaldehyde in aqueous phase.

Macro-Micro Reconfigurable Antenna for Multi Mode & Multi Band(MMMB) Communication Systems (다중 모드 다중 대역(MMMB) 통신 환경을 위한 매크로-마이크로 주파수 재구성 안테나)

  • Yeom, In-Su;Choi, Jung-Han;Jung, Young-Bae;Kim, Dong-Ho;Jung, Chang-Won
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.20 no.10
    • /
    • pp.1031-1041
    • /
    • 2009
  • A small microstrip monopole antenna for macro-micro frequency tuning over multiple bands is presented. The meander-shape antenna is fabricated on a conventional printed circuit board(FR-4, $\varepsilon_r=4.4$ and tan $\delta=0.02$). The antenna operates over WiBro(2.3~2.4 GHz) and WLAN a/b(2.4~2.5 GHz/5.15~5.35 GHz) service bands with an essentially constant antenna gain within each service band. Two diodes, a PIN diode and a varactor, are embedded into the antenna for frequency reconfiguration. The PIN diode is used for frequency switching(macro-tuning) between 2 GHz and 5 GHz bands while the varactor is used for frequency tuning(micro-tuning) within the service bands, 2.3~2.5 GHz and 5.15~5.35 GHz. Unwanted resonances between the two frequency bands(2 GHz and 5 GHz) are suppressed by filling up the gaps between the meander lines. The antenna gain is essentially constant and higher than 2 dBi within each service band. The measured performance of the proposed antenna system suggests the macro-micro frequency tuning techniques be useful in reconfigurable wireless communication systems.

Adsorptive Removal of 2-Methylisoborneol and Geosmin in Raw Water Using Activated Carbon and Zeolite (활성탄과 제올라이트를 이용한 상수원수 중 이취미물질(2-MIB, Geosmin)의 흡착제거)

  • Choi, Jeong-Hwan;Lee, Hong-Jae;Kim, Won-Ju;Park, Hyun-Geoun;Cho, Ju-Sik;Heo, Jong-Soo
    • Korean Journal of Environmental Agriculture
    • /
    • v.20 no.4
    • /
    • pp.244-251
    • /
    • 2001
  • This study was performed to investigate the recovery efficacy of 2-methylisobomeol (2-MIB) and Geosmin, odor contaminants produced by algae, by pretreatment techniques, and also to investigate both adsorption characteristics and removal efficiency to get some information for the effective removal of 2-MIB and Geosmin by batch experiments. In pretreatment experiments, the best recovery efficiency of both odorants at 0.2 and $2\;{\mu}g/L$ in raw water was 30 mL of sampling size, 9 g NaCl for salting out headspace of sampling phase and 40 minutes of adsorption. At the best condition, the recovery efficiency of 2-MIB was 85% at $0.2\;{\mu}g/L$ and 95% at $2\;{\mu}g/L$, whereas the efficiency of Geosmin was lower than that of 2-MIB : 61% at $0.2\;{\mu}g/L$ and 81% at $2\;{\mu}g/L$. In batch experiments, the removal efficiency of the Geosmin and 2-MIB by adsorbents using distilled water were increased in comparison with raw water, the efficiency in raw water was little different by their concentrations. When these results were applied to the Freundrich adsorption isotherm, the K value of 2-MIB for zeolite, coal activated carbon, and coconut activated carbon was 0.671, 1.811, and 1.340, respectively, and the value of Geosmin was 0.6125, 1.771, and 1.5191, respectively. Thus the adsorption efficiency of 2-MIB and Geosmin was in the order of zeolite, coconut activated carbon, coal activated carbon.

  • PDF

Bicycle Riding-State Recognition Using 3-Axis Accelerometer (3축 가속도센서를 이용한 자전거의 주행 상황 인식 기술 개발)

  • Choi, Jung-Hwan;Yang, Yoon-Seok;Ru, Mun-Ho
    • Journal of the Institute of Electronics Engineers of Korea SC
    • /
    • v.48 no.6
    • /
    • pp.63-70
    • /
    • 2011
  • A bicycle is different from vehicles in the structure that a rider is fully exposed to the surrounding environment. Therefore, it needs to make use of prior information about local weather, air quality, trail road condition. Moreover, since it depends on human power for moving, it should acquire route property such as hill slope, winding, and road surface to improve its efficiency in everyday use. Recent mobile applications which are to be used during bicycle riding let us aware of the necessity of development of intelligent bicycles. This study aims to develop a riding state (up-hill, down-hill, accelerating, braking) recognition algorithm using a low-power wrist watch type embedded system which has 3-axis accelerometer and wireless communication capability. The developed algorithm was applied to 19 experimental riding data and showed more than 95% of correct recognition over 83.3% of the total dataset. The altitude and temperature sensor also in the embedded system mounted on the bicycle is being used to improve the accuracy of the algorithm. The developed riding state recognition algorithm is expected to be a platform technology for intelligent bicycle interface system.

Constitutional Legitimacy of the Maritime Cadet Training System : Justifiable Restrictions on the Cadet's Fundamental Rights at the College of Maritime Science of the KMOU (해사대학 승선생활교육의 헌법상 기본권제한에 관한 연구 - 한국해양대학교 해사대학을 중심으로 -)

  • Lee, Sang-Il;Yoo, Jin-Ho;Choi, Jung-Hwan
    • Journal of the Korean Society of Marine Environment & Safety
    • /
    • v.22 no.5
    • /
    • pp.430-443
    • /
    • 2016
  • This paper involves the constitutionality of the restrictive by-laws established by the 'College of Maritime Science' at the 'Korea Maritime and Ocean University' when they affect the cadet's fundamental rights, particularly, in connection with the training system of the 'Merchant Cadet Dormitory.' The issue in question is whether the school regulations may fall within a judicially permissible boundary in light of the general principles of constitutional rights in that the rules are enacted by the school itself in accordance with the Article 31, Section 4 of the Constitution and largely regulate the cadets' living conditions on a campus. However, the general scrutiny standard the courts apply requires the school enactments to pass three tests to be justified: (1) legislative authorization, (2) proportionality and (3) non-infringement on the essential elements of the fundamental rights as articulated under Article 37, Section 2 of the Constitution. The review in this paper shows that, first, the by-laws at issue find themselves statutorily authorized by the 'Higher Education Act' and the 'Decree of the Establishment of National Schools', with the proportionality as a second part observed within a justifiable scope and the essential elements of the fundamental rights as the third point not being marred. In conclusion, the school's dormitory training system is not found to cross the line and, however, the school authorities still need to keep overseeing the overall training course to secure the constitutional proportionality.

Effect of air-contaminated TiN on the deposition characteristics of Cu film by MOCVD (공기 중에 노출된 MOCVD TiN 기판이 MOCVD Cu 증착에 미치는 효과)

  • Choe, Jeong-Hwan;Byeon, In-Jae;Yang, Hui-Jeong;Lee, Won-Hui;Lee, Jae-Gap
    • Korean Journal of Materials Research
    • /
    • v.10 no.7
    • /
    • pp.482-488
    • /
    • 2000
  • The deposition characteristics of Cu film by MOCVD using (hfac)Cu(1,5-COD)(1,1,1,5,5,5-hexafluro-2,4-pentadionato Cu(I) 1,5-cryclooctadiene) as a precursor have been investigated in terms of substrate conditions. Two different substrates such as air-exposed TiN and non-contaminated TiN were used for the MOCVD of Cu. MOCVD of Cu on the air-exposed TiN affected the nucleation rate of Cu as well as its growth, resulting in the Cu films having poor interconnection between particles with relatively small grains. On the other hand, in-situ MOCVD of Cu led to the Cu films having a significantly improved interconnection between particles with larger grains, indicating the resistivity as low as $2.0{\mu}{\Omega}-cm$ for the films having more than 1900$\AA$ thickness. Moreover, better adhesion of Cu films to the TiN by using in-situ MOCVD has been obtained. Finally, initial coalescence mechanism of Cu was suggested in this paper in terms of different substrate conditions by observing the surface morphology of the Cu films deposited by MOCVD.

  • PDF

Physicochemical Properties and Physiological Activities of Ulsan Sweet Persimmon Peel.Flesh According to Cultivars (울산지역 생산 단감 과피.과육의 품종별 이화학적 특성 및 생리활성)

  • Choi, Jeong-Hwan;Lee, Eun-Young;Kim, Gyung-Jin;Park, In-Hae;Kim, Jong-Su;Choi, Gil-Bae;Jung, Su-Geun;Ham, Yu-Sik
    • Applied Biological Chemistry
    • /
    • v.49 no.4
    • /
    • pp.309-314
    • /
    • 2006
  • This study was performed to confirm the physicochemical properties and physiological activities according to cultivar and parts of Ulsan sweet persimmons. The proximate composition of the sweet persimmons was moisture $77.68{\sim}84.65%$, crude ash $0.3{\sim}0.6$, crude fat $0.29{\sim}0.39$ and crude protein $0.52{\sim}0.61%$. Confirmed organic acids and free sugars in sweet persimmons were malic, citric, succinic, and fumaric acids, along with fructose, glucose and sucrose. The major fatty acids were linolenic, vaccenic and palmitic acids. Also, K is the highest mineral in sweet persimmons that accounts for the majority of mineral, more than 60% as $84.9{\sim}103.7mg%$. Contents of vitamin C, total phenolic compounds and flavonoids were the highest in Fuyu peel as 139.91, 169.36 and 60.79mg%, respectively, Electron donating ability and xanthine oxidase inhibition were the highest in Fuyu peel as $30.6{\sim}91.2$ and $26.3{\sim}91.9mg%$, respectively. Nitrite scavenging activity was higher in peel than flesh as $51.0{\sim}76.4mg%$ with slight difference depending on cultivar.

A Study on the Way of Securing the Practical Effectiveness of Oil Record Book (기름기록부 실효성 확보에 관한 연구)

  • Choi, Jung-Hwan;Lee, Sang-Il
    • Journal of the Korean Society of Marine Environment & Safety
    • /
    • v.20 no.4
    • /
    • pp.389-397
    • /
    • 2014
  • The purpose of this thesis is studying for a legal basis and definition of Oil Record Book. In the thesis, comparing with the laws related to punishment for false entry of Oil Record Book of the maritime countries and korea Act. Studying the improvement marine pollutants from ships by suggesting legal and institutional proposal which are able to make themselves increase effectiveness for recording and inspection of Oil Record Book. Suggest the solution of the problems raised in this thesis, First, The Oil Record Book should not be the evidence which is having the effectiveness simply after the accident of marine pollution, but take sanction on pre-inspection of Oil Record Book as establish the concrete administrative punishment for each contents-based record of Oil Record Book. Second, It should set up of judgement criteria of false entry of Oil Record Book by port state control officer. Third, It should strengthen the legal effectiveness of Oil Record Book contents such as Code(c) ; oil residue, Code(d); relating to bilge discharge by including premeditation for false entry of Oil Record Book. Also, The enhancement of role for marine pollution prevention manager raise the effectiveness of Oil Record Book as recognizing the importance of Oil Record Book.