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        검색결과 24

        1.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study aimed to identify factors affecting the duration of traffic incidents in tunnel sections, as accidents in tunnels tend to cause more congestion than those on main roads. Survival analysis and a Cox proportional hazards model were used to analyze the determinants of incident clearance times. METHODS : Tunnel traffic accidents were categorized into tunnel access sections versus inner tunnel sections according to the point of occurrence. The factors affecting duration were compared between main road and tunnel locations. The Cox model was applied to quantify the effects of various factors on incident duration time by location. RESULTS : Key factors influencing mainline incident duration included collision type, driver behavior and gender, number of vehicles involved, number of accidents, and post-collision vehicle status. In tunnels, the primary factors identified were collision type, driver behavior, single vs multi-vehicle involvement, and vehicles stopping in the tunnel after collisions. Incidents lasted longest when vehicles stopped at tunnel entrances and exits. In addition, we hypothesize that incident duration in tunnels is longer than in main roads due to the reduced space for vehicle handling. CONCLUSIONS : These results can inform the development of future incident management strategies and congestion mitigation for tunnels and underpasses. The Cox model provided new insights into the determinants of incident duration times in constrained tunnel environments compared to open main roads.
        4,000원
        2.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : Because a driving simulator typically focuses on analyzing a driver’s driving behavior, it is difficult to analyze the effect on the overall traffic flow. In contrast, traffic simulation can analyze traffic flow, that is, the interaction between vehicles; however, it has limitations in describing a driver’s driving behavior. Therefore, a method for integrating the simulator and traffic simulation was proposed. Information that could be controlled through driving experiments was used, and only the lane-change distance was considered so that a more natural driving behavior could be described in the traffic flow. METHODS : The simulated connection method proposed in this study was implemented under the assumption of specific traffic conditions. The driver’s lane-changing behavior (lane-changing distance, deceleration, and steering wheel) due to the occurrence of road debris was collected through a driving study. The lane-change distance was input as a parameter for the traffic simulation. Driving behavior and safety were compared between the basic traffic simulation setting, in which the driver's driving behavior information was not reflected, and the situation in which the driving simulator and traffic simulation were integrated. RESULTS : The number of conflicts between the traffic simulation default settings (Case 1) and the situation in which the driving simulator and traffic simulation were integrated (Case 2) was determined and compared for each analysis. The analysis revealed that the number of conflicts varied based on the level of service and road alignment of the analysis section. In addition, a statistical analysis was performed to verify the differences between the scenarios. There was a significant difference in the number of conflicts based on the level of service and road alignment. When analyzing a traffic simulation, it is necessary to replicate the driving behavior of the actual driver. CONCLUSIONS : We proposed an integration plan between the driving simulator and traffic simulation. This information can be used as fundamental data for the advancement of simulation integration methods.
        4,300원
        3.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : In this study, the factors affecting the severity of traffic accidents in highway tunnel sections were analyzed. The main lines of the highway and tunnel sections were compared, and factors affecting the severity of accidents were derived for each tunnel section, such as the tunnel access zone and tunnel inner zone. METHODS : An ordered probit model (OPM) was employed to estimate the factors affecting accident severity. The accident grade, which indicates the severity of highway traffic accidents, was set as the dependent variable. In addition, human, environmental, road condition, accident, and tunnel factors were collected and set as independent variables of the model. Marginal effects were examined to analyze how the derived influential factors affected the severity of each accident. RESULTS : As a result of the OPM analysis, accident factors were found to be influential in increasing the seriousness of the accident in all sections. Environmental factors, road conditions, and accident factors were identified as the main influential factors in the tunnel access zone. In contrast, accident and tunnel factors in the tunnel inner zone were found to be the influencing factors. In particular, it was found that serious accidents (A, B) occurred in all sections when a rollover accident occurred. CONCLUSIONS : This study confirmed that the influencing factors and the probability of accident occurrence differed between the tunnel access zone and inner zone. Most importantly, when the vehicle was overturned after the accident occurred, the results of the influencing factors were different. Therefore, the results can be used as a reference for establishing safety management strategies for tunnels or underground roads.
        4,000원
        4.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : It is necessary to implement traffic-control strategies for underground roads. In this study, the application criteria for traffic control were developed to minimize actual traffic congestion on underground roads before it occurs. In particular, the traffic congestion judgement criteria and procedure (TJCAP) were developed. They can specifically classify the possibility of traffic congestion underground. METHODS : A microscopic traffic simulation model was used to analyze different scenarios. With the scenario simulation results, a hierarchical clustering analysis was applied to produce quantitative values from the TJCAP for each experimental network case. RESULTS : For network case (a), it was concluded that the possibility of traffic congestion on underground roads increases when the speed of the ground road connected to the main underground road and the connected ground road after the outflow of the ramp section is low. When the connected road is an interrupted facility after entering the underground roads, the red time is long, and when the section travel speed is 15 km/h, the possibility of traffic congestion underground is highest. A cluster analysis based on these results was performed using two techniques (elbow and silhouette) to verify the final classification. CONCLUSIONS : The TJCAP were designed to operate traffic flow with stricter criteria than traffic congestion management on ground roads. This reflects the difference in the driving environment between underground and above-ground roadways.
        4,200원
        6.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : In this study, model-agnostic methods are applied for interpreting machine learning models, such as the feature global effect, the importance of a feature, the joint effects of features, and explaining individual predictions. METHODS : Model-agnostic global interpretation techniques, such as partial dependence plot (PDP), accumulated local effect (ALE), feature interaction (H-statistics), and permutation feature importance, were applied to describe the average behavior of a machine learning model. Moreover, local model-agnostic interpretation methods, individual conditional expectation curves (ICE), local surrogate models (LIME), and Shapley values were used to explain individual predictions. RESULTS : As global interpretations, PDP and ALE-Plot demonstrated the relationship between a feature and the prediction of a machine learning model, where the feature interaction estimated whether one feature depended on the other feature, and the permutation feature importance measured the importance of a feature. For local interpretations, ICE exhibited how changing a feature changes the interested instance’s prediction, LIME explained the relationship between a feature and the instance’s prediction by replacing the machine model with a locally interpretable model, and Shapley values presented how to fairly contribute to the instance’s prediction among the features. CONCLUSIONS : Model-agnostic methods contribute to understanding the general relationship between features and a prediction or debut a model from the global and/or local perspective, securing the reliability of the learning model.
        4,500원
        7.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적 : 본 연구는 20대가 선호하는 안경집 디자인의 핵심 요소를 도출하고자 실시되었다. 방법 : 서울지역 거주 대학생 집단을 대상으로 3단계에 걸쳐 설문조사를 시행하였다. 다양한 안경집 디자인의 예제들을 수집하고 선호도 조사를 진행한 다음, 도출된 안경집 디자인을 대상으로 SD법을 바탕으로 하는 감성평가 및 요인분석을 실시하여 그 결과를 분석하였다. 결과 : 분석 결과 고유값 1을 기준으로 8개의 감성어휘가 도출되어 2개의 축으로 분류되었다. 선호도 조사에서 상위를 차지한 안경집 디자인들에서는 실용적인, 단순한, 가벼운, 단단한, 깔끔한 등의 감성언어에 대응되는 제 1 요인과 고급스러운, 둥근, 무광의 등의 감성언어에 대응되는 제 2요인이 높게 나타났으며 반대로 하위를 차지한 안경집 디자인에서는 제 1요인과 제 2요인이 낮게 나타났다. 결론 : 20대 소비자 집단은 기능성과 심미성을 주요소로 하여 안경집 디자인을 선택하는 경향이 존재하는 것으 \로 나타났다.
        4,800원
        9.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        마비성 패독(paralytic shellfish poisoning, PSP)에 의한 중독은 와편모조류(Dinoflagellates)가 생성하는 saxitoxin (STX)이 이매패류 등의 먹이활동에 의해 축적되고 이를 사람이 섭취함으로써 발생한다. 최근 분석기술의 발전으로 와편모조류가 STX외에도 gonyautoxin (GTX) group 및 Nsulfo carbamoyl toxins (C toxin) group 등 다양한 유사체들 을 생성하는 것으로 보고되고 있다. 이에 CODEX, EFSA 에서는 STX외 유사체의 안전관리를 위해 STX 및 유사체를 STX group으로 관리하고자 하는 움직임을 보이고 있다 . 국내의 경우도 STX 유사체를 생성하는 조류의 발생이 이미 보고되고 있으며 실제 홍합에서 유사체의 오염사례도 소수 보고되고 있다. 따라서 국제적인 움직임에 발맞추어 국내에서도 STX 및 유사체의 group 관리를 위한 준비가 필요할 것으로 사료된다. 본 연구에서는 STX 및 유사체의 체계적인 모니터링 및 안전관리의 기반을 마련하고자 STX 및 유사체의 이화학적 특성, 생성조류, 국내외 발생현황, 독성 및 상대독성계수, 분석법, 오염현황 및 관리현황에 대한 폭넓은 검토를 수행하고자 하였다.
        4,600원
        13.
        2020.10 KCI 등재 서비스 종료(열람 제한)
        본 연구에서 상동나무 가지 추출물(STB-E100)은 대장암 세포에서 세포사멸을 유도하여 세포생육을 억제하였다. 또한 Iκ B-α 인산화를 통한 IκB-α 단백질 분해를 유도하며 이로 인해 P65 핵내 전이를 유도하여 NF-κB 신호전달을 활성화시킨다. NF-κB 신호전달 활성화는 GSK3β 활성화를 통해 P65 핵내 전 이를 유도에 의한 것이지만 IκB-α분해는 GSK3β 의존성이 아니다. 상동나무 가지 추출물은 이러한 신호전달 활성화를 통해 세포사멸을 유도하여 대장암의 세포생육을 억제한다. 본 결과를 바탕으로 상동나무 가지가 암 예방 및 치료를 목적으로한 표적 요법에서 항암제 개발의 잠재적 활용 소재로서 이용 가능하다고 사료된다. 그러나 대장암 세포에서 상동나무 가지 추출물에 의해 유도된 NF-κB 신호전달 작용기전을 좀 더 구체적으로 구명할 필요가 있고 대장암에 대한 세포사멸과 작용기전의 정확한 관련성을 조사하기 위해 추가적인 연구가 필요하다.
        14.
        2019.04 KCI 등재 서비스 종료(열람 제한)
        In this study, we evaluated the effect of branch (STB) and leave (STL) extracts from Sageretia thea on β-catenin level in human colorecal cancer cells, SW480 and lung cancer cells, A549. STB and STL dose-dependently suppressed the growth of SW480 and A549 cells. STB and STL decreased β-catenin level in both protein and mRNA level. MG132 decreased the downregulation of β-catenin protein level induced by STB and STL. However, the inhibition of GSK3β by LiCl or ROS scavenging by NAC did not block the reduction of β-catenin protein by STB and STL. Our results suggested that STB and STL may downregulate β-catenin protein level independent on GSK3β and ROS. Based on these findings, STB and STL may be a potential candidate for the development of chemopreventive or therapeutic agents for human colorectal cancer and lung cancer.
        15.
        2019.04 KCI 등재 서비스 종료(열람 제한)
        In this study, we evaluated the anti-cancer activity and potential molecular mechanism of 70% ethanol extracts of branches from Taxillus yadoriki parasitic to Neolitsea sericea (TN-NS-B) against human lung cancer cells, A549. TY-NS-B dose-dependently suppressed the growth of A549 cells. TY-NS-B decreased β-catenin protein level, but not mRNA level in A549 cells. The downregulation of β-catenin protein level by TY-NS-B was attenuated in the presence of MG132. Although TY-NS-B phosphorylated β-catenin protein, the inhibition of GSK3β by LiCl did not blocked the reduction of β-catenin by TY-NS-B. In addition, TY-NS-B decreased β-catenin protein in A549 cells transfected with Flag-tagged wild type β- catenin or Flag-tagged S33/S37/T41 mutant β-catenin construct. Our results suggested that TN-NS-B may downregulate β- catenin protein level independent on GSK3β-induced β-catenin phosphorylation. Based on these findings, TY-NS-B may be a potential candidate for the development of chemopreventive or therapeutic agents for human lung cancer.
        16.
        2018.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        본 연구는 고지방 식이로 유발된 내당능 장애 모델의 학습 및 기억력 장애에 대한 스피룰리나 섭취의 개선 효과를 확인하고자 하였다. 당부하 검사(IPGTT)를 통하여 고지방식이를 통한 내당능 장애가 유발되었음을 확인하였고, SP는 HFD 대비 약 20%의 당 내성 개선효과를 나타내는 것으로 나타났다. 고지방 식이로 인지 기능 손상을 유발시킨 동물모델의 Y-maze 및 Morris water maze 시험을 진행한 결과는 SP에서 CND 대비 학습 및 장·단기기억력 장애가 유의한 수준으로 개선됨을 확인하였다. 실험동물의 혈청분석 결과는 스피룰리나 섭취가 일반식이로 전환한 것과 비교하였을 때, HFD 대비 LDLC 감소 및 HTR(HDLC의 비율) 증가를 통한 혈중 콜레스테롤 개선에 효과를 나타냈다. 적출된 뇌와 간 조직을 대상으로 SOD 활성, oxidized GSH 함량 및 MDA 함량을 측정한 결과 스피룰리나 섭취가 뇌조직뿐만 아니라 간 조직에서 항산화 활성을 향상시켜 주는 것도 역시 확인할 수 있었다. 이러한 결과는 고지방 식이를 통한 혈당 상승 및 이로 인한 기억능력 저하에서 스피룰리나 섭취는 CND 수준으로의 개선 효과를 유도할 수 있음을 확인하였다. 또한, 스피룰리나 섭취는 뇌 기능과 직접적으로 연관된 콜린성 시스템 손상에도 CND 대비 AChE 활성에 더 높은 저해효과를 나타냄을 확인하였다. 따라서 본 연구는 스피룰리나가 고지방 식이로 유도된 내당능 장애 모델에서 발생될 수 있는 뇌기능 저하에서 혈중 콜레스테롤 개선 효과, 항산화 효과 및 AChE 저해효과를 통하여, 비만으로 유도될 수 있는 대사성 인지 장애에 대한 개선 소재로의 잠재적인 가능성을 갖는 것으로 판단된다.
        17.
        2018.05 서비스 종료(열람 제한)
        Background : Although the inhibitory effect of mistletoe on cancer cell growth has been reported, the underlying mechanisms to explain its anti-proliferative activity are not fully studied. Thus, we elucidated the potential molecular mechanism of the branch from taxillus yadoriki (TY) parasitic to Neolitsea sericea (NS) (TY-NS-B) for the anti-proliferative effect. Methods and Results : In comparison of anti-proliferative effect of TY from the host trees such as Cryptomeria japonica (CJ), Neolitsea sericea (NS), Prunus serrulata (PS), Cinnamomum camphora (CC) and Quercus acutissima (QA), TY-NS showed higher anti-cell proliferative effect than TY-CJ, TY-PS, TY-CC or TY-QA. In addition, the anti-proliferative effect of branch from TY from all host trees was better than leaves. Thus, we selected the branch from Taxillus yadoriki parasitic to Neolitsea sericea (TY-NS-B) for the further study. TY-NS-B inhibited the cell proliferation in the various cancer cells and downregulated cyclin D1 protein level. MG132 treatment attenuated cyclin D1 downregulation of cyclin D1 protein level by TY-NS-B. In addition, TY-NS-B increased threonine-286 (T286) phosphorylation of cyclin D1, and the mutation of T286 to alanine (T286A) blocked cyclin D1 proteasomal degradation by TY-NS-B. But the upstream factors related to cyclin D1 degradation such as ERK1/2, p38, JNK, GSK3β, PI3K, IκK or ROS did not affect cyclin D1 degradation by TY-NS-B. However, LMB treatment was observed to inhibit cyclin D1 degradation by TY-NS-B, and T286A blocked cyclin D1 degradation through suppressing cyclin D1 redistribution from nucleus to cytoplasm by TY-NS-B. In addition, TY-NS-B activated CRM1 expression. Conclusion : Our results suggest that TY-NS-B may suppress cell proliferation by downregulating cyclin D1 protein level through proteasomal degradation via T286 phosphorylation-dependent cyclin D1 nuclear export. These findings will provide the evidence that TY-NS-B has potential to be a candidate for the development of chemoprevention or therapeutic agents for human cancer.
        18.
        2018.05 서비스 종료(열람 제한)
        Background : Vaccinium oldhamii is a Korean native tree, which is deciduous and shrub tree with broad leaf. It was used primarily for edible or medicinal purposes for bladder infection in Korea and China. In addition, it has been reported to be used for treating inflammation, gonorrhea, vomiting, diarrhea and eruption. In this study, we evaluated the anti-inflammatory effect of the branch of Vaccinium oldhamii and elucidated the potential mechanisms in LPS-stimulated RAW264.7 cells. Methods and Results : In the comparative experiment for the inhibitory effect of the plant parts from Vaccinium oldhamii such as fruits, leaves and branches on NO production, we observed that the branch extracts showed the highest inhibitory effect. Thus, the further study was performed using the branch of Vaccinium oldhamii (VOB). VOB did not affect iNOS expression but significantly IL-1β expression, which indicates that VOB may block NO production through the inhibition of IL-1β expression. In elucidation of the potential mechanisms for anti-inflammatory effect, VOB inhibited the degradation of IκB-α which results in the inhibition of p65 nuclear accumulation and NF-κB activation. In addition, VOB suppressed the activation of ERK1/2, p38 and JNK. Conclusion : These results indicate that VOB may exert anti-inflammatory activity through the inhibiting NF-κB and MAPK signaling. From these findings, VOB has potential to be a candidate for the development of chemoprevention or therapeutic agents for the inflammatory diseases.
        19.
        2018.05 서비스 종료(열람 제한)
        Background : Hibiscus syriacus is a widely cultivated ornamental shrub, found throughout eastern and southern Asia. The root of H. syriacus has been used in Asian folk medicine as a fungicide, antipyretic, and anthelmintic in the treatment of dysentery, eczema, tinea, and scabies. In this study, we evaluated the anti-inflammatory effect of 70% ethanol extracts of root from Hibiscus syriacus (RHS-E70) and elucidated the potential mechanisms in LPS-stimulated RAW264.7 cells. Methods and Results : RHS-E70 dose-dependently suppressed nitric oxide (NO) production in LPS-stimulated RAW264.7 cells. In addition, RHS-E70 attenuated LPS-mediated overexpression of iNOS and IL-1β. In elucidation of the potential mechanisms for anti-inflammatory effect, RHS-E70 inhibited the phosphorylation and subsequent degradation of IκB-α, which results in the inhibition of p65 nuclear accumulation and NF-κB activation. In addition, RHS-E70 suppressed the activation of ERK1/2 and p38, which results in the inhibition of ATF2 phosphorylation and subsequent ATF2 nuclear accumulation. Conclusion : These results indicate that RHS-E70 may exert anti-inflammatory activity through the inhibiting NF-κB and MAPK signaling. From these findings, RHS-E70 has potential to be a candidate for the development of chemoprevention or therapeutic agents for the inflammatory diseases.
        20.
        2018.05 서비스 종료(열람 제한)
        Background : Ginseng (Panax ginseng) has been reported to exert an anti-inflammatory activity in a variety of inflammatory. However, inflammation-regulatory activity of wood-cultivated ginseng has not been thoroughly evaluated. In this study, we evaluated the anti-inflammatory effect of wood-cultivated ginseng and elucidated the potential mechanisms in LPS-stimulated RAW264.7 cells. Methods and Results : Inhibitory effects of the old wood-cultivated ginseng (WCG-O), young wood-cultivated ginseng (WCG-Y) and ginseng (G) on NO and PGE2 production were examined using the Griess assay and ELISA kit. Suppressive effects of WCG-O on inflammatory gene expression, transcriptional activation, and inflammation signaling events were investigated using Western blot analysis, RT-PCR analysis and luciferase activity reporter gene assay. WCG-O dose-dependently suppressed nitric oxide (NO) and Prostaglandin E2 (PGE2) production in LPS-stimulated RAW264.7 cells. In addition, WCG-O attenuated LPS-mediated overexpression of iNOS and COX-2. In addition, WCG-O blocked the expression of TNF-α and IL-1β in LPS-stimulated RAW264.7 cells. In elucidation of the potential mechanisms for anti-inflammatory effect, WCG-O inhibited the activation of IκK-α/β, the phosphorylation of IκB-α, and degradation of IκB-α, which results in the inhibition of p65 nuclear accumulation and NF-κB activation. In addition, WCG-O suppressed the activation of ERK1/2, p38 and JNK, which results in the inhibition of ATF2 nuclear accumulation. Conclusion : These results indicate that WCG-O may exert anti-inflammatory activity through the inhibiting NF-κB and MAPK signaling. From these findings, WCG-O has potential to be a candidate for the development of chemoprevention or therapeutic agents for the inflammatory diseases.
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