• 로봇학회논문지
• /
• 제17권1호
• /
• pp.40-47
• /
• 2022

A reward function suitable for a task is required to manipulate objects through reinforcement learning. However, it is difficult to design the reward function if the ample information of the objects cannot be obtained. In this study, a demonstration-based object manipulation algorithm called stochastic exploration guided by demonstration (SEGD) is proposed to solve the design problem of the reward function. SEGD is a reinforcement learning algorithm in which a sparse reward explorer (SRE) and an interpolated policy using demonstration (IPD) are added to soft actor-critic (SAC). SRE ensures the training of the critic of SAC by collecting prior data and IPD limits the exploration space by making SEGD's action similar to the expert's action. Through these two algorithms, the SEGD can learn only with the sparse reward of the task without designing the reward function. In order to verify the SEGD, experiments were conducted for three tasks. SEGD showed its effectiveness by showing success rates of more than 96.5% in these experiments.

• Advances in aircraft and spacecraft science
• /
• 제10권5호
• /
• pp.457-471
• /
• 2023

The paper evaluates the aerodynamic coefficients on a blunt-nose re-entry capsule with a conical cross-section followed by a cone-flare body. A computer code is developed to solve three-dimensional compressible inviscid equationsfor flow over a Space Recovery Experiment (SRE) configuration at different flare-cone half-angle at Mach 6 and angle of attack up to 5°, at 1° interval. The surface pressure variation is numerically integrated to obtain the aerodynamic forces and pitching moment. The numerical analysis reveals the influence of flare-cone geometry on the flow characteristics and aerodynamic coefficients. The numerical results agree with wind tunnel results. Increase of cone-flare angle from 25° to 35° results in increase of normal force slope, axial forebody drag, base drag and location of centre of pressure by 62.5%, 56.2% and 33.13%, respectively, from the basic configuration ofthe SRE of 25°.

• 한국응용과학기술학회지
• /
• 제37권5호
• /
• pp.1239-1247
• /
• 2020

한국 자생식물인 기린초(Sedum kamtschaticum Fisch.)는 열수 추출 형태로 혈액 순환 개선과 항산화 및 항염증 효과를 내는 한약재로 사용되어왔다. 선행연구를 통해 기린초 여러 부위에서 우수한 항산화 효과를 확인하여, 본 연구에서는 기린초의 줄기(Stem)와 뿌리(Root) 부위를 각각 70% ethanol (SKS, SKR)로 추출한 후, n-hexane (SSH), ethyl acetate (SSE, SRE), chloroform (SSC, SRC) 및 water (SSW, SRW) 순서로 용매 극성별로 분획하여 화장품 소재로서 응용 가능성을 확인하였다. 각 분획물마다 총 폴리페놀 함량, 플라보노이드 함량 및 DPPH 라디칼 소거능을 확인한 결과 뿌리추출물(SKR)이 줄기추출물(SKS)보다 우수한 함량과 효과를 나타냈고, 전체적으로 ethyl acetate 분획물(SSE, SRE)이 가장 효과가 우수했다. 또한, tyrosinase 활성 저해 효과도 ethyl acetate 분획물이 가장 우수하였고, 모든 분획물은 세포독성이 없는 10 ㎍/mL 농도에서 B16F10 멜라노마 세포에 처리했을 때 우수한 멜라닌 생성 저해력을 보였다. 70% ethanol 추출물(SKS, SKR)에 대해 HPLC 분석 시 gallic acid와 quercetin을 포함한 플라보노이드가 검출되었다. 본 연구에서는 기린초의 피부 항산화 효과와 미백효과를 나타내는 기능성화장품 천연소재로서 응용 가능성을 제시한다.

• 한국영양학회:학술대회논문집
• /
• 한국영양학회 2003년도 추계학술대회 및 정기총회
• /
• pp.139-139
• /
• 2003

• Molecules and Cells
• /
• 제26권5호
• /
• pp.462-467
• /
• 2008

TPA is known to cooperate with an activated Ras oncogene in the transformation of rodent fibroblasts, but the biochemical mechanisms responsible for this effect have not been established. In the present study we used c-fos promoter-luciferase constructs as reporters, in transient transfection assays, in NIH3T3 cells to assess the mechanism of this cooperation. We found a marked synergistic interaction between TPA and a transfected v-Ha-ras oncogene in the activation of c-fos promoter and SRE. SRE has binding sites for TCF and SRF. A dominant-negative Ras (ras-N17) inhibited the TPA-Ras synergy by blocking the PKC-MAPK-TCF pathway. Dominant-negative RhoA and Rac1 (but not Cdc42Hs) inhibited the TPA-Ras synergy by blocking the Ras-Rho-SRF signaling pathway. Constitutively active $PKC{\alpha}$ and $PKC{\varepsilon}$ showed synergy with v-Ras. These results suggest that the activation of two distinct pathways such as Ras-Raf-ERK-TCF pathway and Rho-SRF pathway are responsible for the induction of c-fos by TPA and Ras in mitogenic signaling pathways.

• International Journal of Computer Science & Network Security
• /
• 제24권5호
• /
• pp.40-52
• /
• 2024

Cyber-Physical Systems (CPS) are introduced as complex, interconnected systems that combine physical components with computational elements and networking capabilities. They bridge the gap between the physical world and the digital world, enabling the monitoring and control of physical processes through embedded computing systems and networked communication. These systems introduce several security challenges. These challenges, if not addressed, can lead to vulnerabilities that may result in substantial losses. Therefore, it is crucial to thoroughly examine and address the security concerns associated with CPS to guarantee the safe and reliable operation of these systems. To handle these security concerns, different existing security requirements methods are considered but they were unable to produce required results because they were originally developed for software systems not for CPS and they are obsolete methods for CPS. In this paper, a Security Requirements Engineering Methodology for CPS (CPS-SREM) is proposed. A comparison of state-of-the-art methods (UMLSec, CLASP, SQUARE, SREP) and the proposed method is done and it has demonstrated that the proposed method performs better than existing SRE methods and enabling experts to uncover a broader spectrum of security requirements specific to CPS. Conclusion: The proposed method is also validated using a case study of the healthcare system and the results are promising. The proposed model will provide substantial advantages to both practitioners and researcher, assisting them in identifying the security requirements for CPS in Industry 4.0.

• 멤브레인
• /
• 제27권3호
• /
• pp.240-247
• /
• 2017

본 연구에서는 막 결합형 축전식 탈염공정에 적용을 위해 폴리비닐플루오라이드를 고분자 지지체로 사용하여 양이온 및 음이온교환수지를 배합하여 제작된 불균질 이온교환막을 탄소전극에 결합하여 염 제거 효율을 알아보고자 하였다. 불균질 이온교환막의 배합 조건은 용매, 고분자 지지체, 이온교환수지를 7 : 2 : 1의 무게 비율로 하였으며 탄소전극에 직접 캐스팅 하였다. 운전조건으로 공급액은 주로 NaCl 수용액에 대하여 흡착전압, 시간, 공급액의 농도, 유속, 탈착전압, 시간 등에 대하여 염 제거 효율을 측정하였으며 이 외에 $CaCl_2$과 $MgSO_4$ 수용액에 대하여서도 측정하였다. 대표적으로 NaCl 100 mg/L 용액의 15 mL/min에서 1.5 V, 3분의 흡착조건, -0.1 V, 3분의 탈착조건에서 98%의 염 제거 효율을 보였으며, $CaCl_2$과 $MgSO_4$는 100 mg/L, 15 mL/min에서 1.2 V, 3분의 흡착조건, -0.5 V, 5분의 탈착조건에서 각각 70, 59%의 염 제거 효율을 보였다.

• 생명과학회지
• /
• 제20권2호
• /
• pp.202-207
• /
• 2010

Ras 유전자는 30%의 인간암에서 변이가 발견되며 세 종류의 isoform, H-Ras, K-Ras 및 N-Ras로 구성되어 있다. Ras 단백질의 CAAX motif에 farnesylation과 같은 번역 후 변형은 Ras의 활성에 필수 요소이다. 본 연구에서는 새로운 farnesyl transferase 억제제인 YH3938과 YH3945의 발암원성 H-Ras, K-Ras 및 N-Ras의 작용에 대한 영향을 조사하였다. YH3938과 YH3945는 발암원성 H-Ras에 의해 형질전환된 Rat2 세포의 증식과 형태 변화를 억제하였으나 K-Ras에 대해서는 효과가 없었다. N-Ras에 대해서는 약한 영향이 있었다. H-Ras와 N-Ras에 의한 SRE promoter 활성화는 YH3938과 YH3945에 의해 억제되었으나, K-Ras에는 영향이 없었다. Ras 단백질의 bandshift 분석을 통해 YH3938은 H-Ras와 N-Ras의 번역 후 변환을 억제하였으나, K-Ras에는 영향이 없었다. YH3945는 H-Ras의 변환에만 영향이 있었다. 결론적으로 YH3938과 YH3945는 H-Ras의 farnesylation을 억제하여 그 발암원성을 억제하며, YH3938은 N-Ras 작용을 농도의존적으로 억제하며, K-ras에 대해서는 영향이 없음을 알 수 있었다.

• BMB Reports
• /
• 제43권1호
• /
• pp.17-22
• /
• 2010

In this study, a novel member of BTB-kelch proteins, named KBTBD7, was cloned from a human embryonic heart cDNA library. The cDNA of KBTBD7 is 3,008 bp long and encodes a protein product of 684 amino acids (77.2 kD). This protein is highly conserved in evolution across different species. Western blot analysis indicates that a 77 kD protein specific for KBTBD7 is wildly expressed in all embryonic tissues examined. In COS-7 cells, KBTBD7 proteins are localized to the cytoplasm. KBTBD7 is a transcription activator when fused to GAL4 DNA-binding domain. Deletion analysis indicates that the BTB domain and kelch repeat motif are main regions for transcriptional activation. Overexpression of KBTBD7 in MCF-7 cells activates the transcriptional activities of activator protein-1 (AP-1) and serum response element (SRE), which can be relieved by siRNA. These results suggest that KBTBD7 proteins may act as a new transcriptional activator in mitogen-activated protein kinase (MAPK) signaling.

• International Journal of Reliability and Applications
• /
• 제9권1호
• /
• pp.79-93
• /
• 2008

The aim of this work is to generalize reliability equivalence techniques to apply them to a system consists of two independent and non-identical components connected in series(parallel) system, that have constant failure rates. We shall improve the system by using one component only. We start by establishing two different types of reliability equivalence factors, the survival reliability equivalence (SRE) and mean reliability equivalence (MRE) factors. Our second studies, introducing some applications for our studies in airports and our life. Also, we introduced some numerical results.