• Title/Summary/Keyword: Time complexity

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Wildfire-induced Change Detection Using Post-fire VHR Satellite Images and GIS Data (산불 발생 후 VHR 위성영상과 GIS 데이터를 이용한 산불 피해 지역 변화 탐지)

  • Chung, Minkyung;Kim, Yongil
    • Korean Journal of Remote Sensing
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    • v.37 no.5_3
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    • pp.1389-1403
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    • 2021
  • Disaster management using VHR (very high resolution) satellite images supports rapid damage assessment and also offers detailed information of the damages. However, the acquisition of pre-event VHR satellite images is usually limited due to the long revisit time of VHR satellites. The absence of the pre-event data can reduce the accuracy of damage assessment since it is difficult to distinguish the changed region from the unchanged region with only post-event data. To address this limitation, in this study, we conducted the wildfire-induced change detection on national wildfire cases using post-fire VHR satellite images and GIS (Geographic Information System) data. For GIS data, a national land cover map was selected to simulate the pre-fire NIR (near-infrared) images using the spatial information of the pre-fire land cover. Then, the simulated pre-fire NIR images were used to analyze bi-temporal NDVI (Normalized Difference Vegetation Index) correlation for unsupervised change detection. The whole process of change detection was performed on a superpixel basis considering the advantages of superpixels being able to reduce the complexity of the image processing while preserving the details of the VHR images. The proposed method was validated on the 2019 Gangwon wildfire cases and showed a high overall accuracy over 98% and a high F1-score over 0.97 for both study sites.

A Digital Twin Software Development Framework based on Computing Load Estimation DNN Model (컴퓨팅 부하 예측 DNN 모델 기반 디지털 트윈 소프트웨어 개발 프레임워크)

  • Kim, Dongyeon;Yun, Seongjin;Kim, Won-Tae
    • Journal of Broadcast Engineering
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    • v.26 no.4
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    • pp.368-376
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    • 2021
  • Artificial intelligence clouds help to efficiently develop the autonomous things integrating artificial intelligence technologies and control technologies by sharing the learned models and providing the execution environments. The existing autonomous things development technologies only take into account for the accuracy of artificial intelligence models at the cost of the increment of the complexity of the models including the raise up of the number of the hidden layers and the kernels, and they consequently require a large amount of computation. Since resource-constrained computing environments, could not provide sufficient computing resources for the complex models, they make the autonomous things violate time criticality. In this paper, we propose a digital twin software development framework that selects artificial intelligence models optimized for the computing environments. The proposed framework uses a load estimation DNN model to select the optimal model for the specific computing environments by predicting the load of the artificial intelligence models with digital twin data so that the proposed framework develops the control software. The proposed load estimation DNN model shows up to 20% of error rate compared to the formula-based load estimation scheme by means of the representative CNN models based experiments.

Integer Programming-based Operation Sequencing for Multi-operation on Single Machine (정수계획법을 통한 다중작업 수행 단일기계에서의 작업순서 결정)

  • Park, Seonyeong;Shin, Moonsoo
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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    • v.9 no.3
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    • pp.261-270
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    • 2019
  • With the advent of the Fourth Industrial Revolution, multi-variety production in the up-to-date manufacturing environment is proceeding more rapidly whereby production planning and management have been getting more complicated. Moreover, the need to improve production efficiency through effective operation sequencing is further heightened. Fundamentally, the effective operation sequencing can reduce the set-up of the equipment, efficiently utilize the equipment, shorten the set-up time, and ultimately contribute to productivity improvement. This study deals with the problem of efficient operation sequencing in a situation where a single machine performs multiple operations. The complexity of the problem is very high when compared to the case where only one operation is performed on one machine, which is covered in most existing studies. In this paper, we propose an integer programming model to minimize the number of setups. This study aims at minimizing the number of mold replacement times in the process of processing a given production order for the wiring harness manufacturing process, which is one of the components of automobile electric field. In addition, brief case studies are presented to verify the validity of the proposed mathematical model.

A study on 3D safety state information platform architecture design for realistic disaster management based on spatial information (공간정보 기반 실감형 재난관리를 위한 3D 안전상태정보 플랫폼 아키텍처 설계 방안에 대한 연구)

  • Kim, Taehoon;Youn, Junhee
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.4
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    • pp.564-570
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    • 2019
  • Although some studies have been attempted to utilize 3D spatial information for fire safety and disaster management, it is still not enough to apply it to actual work. Especially, in case of multi-use facilities, many facilities are more vulnerable to rapid response in the event of a disaster due to complexity of facilities, diversity of usage, and specificity of users. In this paper, we propose a method to develop a 3D safety status information platform that combines 3D spatial information and time - varying safety status information for efficient disaster management of multi-use facilities. In detail, first, we analyze the use cases of existing disaster management platform and the needs of business users. Second, based on the analyzed results, target facilities were selected and possible scenarios were created. Finally, we developed platform architecture design and service development strategy. The research results will be used as a basis for future 3D safety status information platform development. This will contribute to improving the safety of multi-use facilities and minimizing damage to disaster vulnerable groups.

Improvement of Basic Design Process for Submarines by Integration of SE-Based Technical Review and Requirements Management Process (SE 기반 기술검토 및 요구사항 관리 프로세스의 통합을 통한 잠수함 기본설계 프로세스의 개선)

  • Shin, Sung-Chul;Park, Jin-Won;Lee, Jae-Chon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.11
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    • pp.96-104
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    • 2018
  • Military vessels are complex weapon systems consisting of various integrated onboard equipment. Since their acquisition of military equipment takes a long period of time and a prototype ship is deployed and tested, vessel development has relied on its proprietary process. However, due to the growing complexity of onboard equipment technology, application of systems engineering (SE) process has become indispensable. Nonetheless, an effective design process complementing the existing design with the SE has not yet been developed. As such, we have studied an improved basic design process for submarines based on SE. To do so, we analyzed the processes for the basic design, technical review, and requirement management. Included reviews and requirements are SRR, SFR and PDR, and SSRS, SSS, and SSDD. By combining the results in the SE framework, we built an improved basic design process that can be applied in parallel with the SE-based technical review and requirement management. To assess the process, we applied our proposed model to the submarine development undergoing the basic design phase. It is possible to effectively manage the requirements, design artifacts and improve traceability, and also utilize them as test and evaluation materials. The SE-based basic design process is expected to be useful in other kinds of vessel design.

Investigation on Perceptions, Attitudes, and Contributing Factors to Spontaneous Adverse Drug Reaction Reporting among Community Pharmacists: Results from a Web-based Survey (지역 약사의 자발적 부작용 보고에 대한 인식 및 태도와 영향요인 조사: 설문조사 결과를 중심으로)

  • Lee, Mo-Se;Choi, Ah-Hyung;Jang, Bo-Hyun;Kim, Na-Young;Lee, Jung-Min;Shin, Ju-Young;Jeon, Ha-Lim
    • Korean Journal of Clinical Pharmacy
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    • v.29 no.2
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    • pp.125-132
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    • 2019
  • Objective: To examine the perceptions and attitudes toward spontaneous adverse drug reaction (ADR) reporting system among community pharmacists and identify factors that influence reporting, by implementing a survey. Methods: A structured questionnaire was developed and distributed online. Request for the survey was posted on the website of pharmacy's billing program, and the survey was conducted for 8 days. We collected the participants' response on their work environment, experience of ADR reporting, and their perception and attitude on the reporting system. Multivariate logistic regression was used to evaluate factors influencing ADR reporting. Results: A total of 382 pharmacists participated in the survey. Significant contributing factors for reporting level were age (odds ratio [OR], 0.90; 95% confidence interval [CI], 0.84-0.96), knowledge of reporting method (OR, 53.56; 95% CI, 9.10-315.41), installation of reporting program (OR, 31.92; 95% CI, 4.16-244.75), and encouragement from the Korean pharmaceutical association (OR, 4.13; 95% CI, 1.11-15.35). Regarding the attitude toward spontaneous ADR reporting system, 'lack of time for reporting' (OR, 0.29; 95% CI, 0.15-0.53) and 'complexity of reporting procedure' (OR, 0.51; 95% CI, 0.31-0.84), were associated with a low likelihood of reporting. Conclusion: Our results indicated that the knowledge of ADR reporting method, installation of the reporting program, and encouragement from the Korean Pharmaceutical Association contribute to active reporting. It is necessary to simplify the reporting method, make the ADR reporting program user-friendly, and provide educational interventions to increase participation in spontaneous reporting by the community pharmacists.

A Strategy for the Risk Assessment of Abandoned Mine Filler Materials (비산재가 포함된 폐광산 채움재의 위해성 평가 전략)

  • Ji, Sangwoo;Jo, Hwanju;Shin, Hee-young;Lee, Sang-hun;Ahn, Ji-Whan
    • Resources Recycling
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    • v.28 no.4
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    • pp.59-64
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    • 2019
  • This study suggests a conceptual strategy and methodology for the risk assessment of the domestic abandoned mine fillers with fly ash. The fillers are composed of coal fly ash and solidification materials, and contain little toxic substances such as carbonates but also some heavy metals; therefore, those requires a risk assessment. The risk assessment should primarily focus on estimation of the effects to human health both on carcinogen and non-carcinogen aspects. The significant data such as toxicity and partition coefficients can be obtained from the national soil or mine environmental risk assessment guidelines. Accurate risk assessment of heavy metal contamination in the fillers may consume lots of time and efforts through site survey and instrumental analyses, etc. Moreover, it is inefficient to explore all of the factors as concentrations and categories in every heavy metal in the fillers, due to a high variety and complexity. Therefore, implementation of a preliminary risk assessment is suggested by using the literature data and the basic characteristics of the filler samples prior to the detailed risk assessment. Certainly, this presumes a thorough understanding of reliable sample analysis methods, exposure pathways, and relevant physicochemical and biological mechanisms.

A Study of Technician's Activity belonging to Gukjangdogam in Joseon (조선시대 국장도감 소속 공장의 활동 연구)

  • Park, Jong-min
    • Korean Journal of Heritage: History & Science
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    • v.40
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    • pp.325-355
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    • 2007
  • A national funeral was a ceremony for king symbolizing a country in Joseon. The Gukjangdogam had three practical affairs: ibang and ibang, sambag. Each practial affairs was ready for various implement and finished a national funeral very well. So various important. The Daeyeo and the Gyeonyeo which carried directly the dead from a palace to a burial in the national funeral was a chief implements to handle with careful. All people had to carry heartily him as a Daehaewang which means a previous king. But three practical affairs belonging to the Gukjangdogam made various implements directly or indirectly related in a Daehaengwang and symbolized has authority. They were related in succeeding to the throne. The departure of a funeral in Joseon was a space and a time to appear his authority. The Gukjangdogam progressed it like going in and out the palace in the life. We knew it was ready for the departure of a funeral equalizing to the life and the death. The Gukjangdogam made the best of various implements using in going in and out the palace in the departure. We saw the Confucian view about living and dying through the implements used in the departure. The Gukjangdogam assembled many technicians around the country. They had to make various implements as high-level technicians at certain hour under the supervision of officials. The Gukjangdogam payed and compensated for their labors. There is an indissoluble connection between them. The technicians belonging to three practical affairs were ready for the implements for a national funeral: newly-made and repair, existed-implements use etc. So a national funeral can be called 'the feast of techniques' as well as complexity of techniques' in the Joseon.

Teacher Perception and Practice on Free Semester Science Assessment (자유학기제 과학과 평가에 대한 교사의 인식과 실제)

  • Kim, Yura;Choi, Aeran
    • Journal of The Korean Association For Science Education
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    • v.39 no.1
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    • pp.143-160
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    • 2019
  • This study investigated 15 science teachers' perception and practice on free semester and science assessment. We analyzed frequencies of teacher choice for closed questions and used constant comparative method for teacher description and individual interview. Most teachers determined a low ranking for changes in assessment methods and mentioned a lack of objectivity on free semester assessment, unsystematic free semester assessment, and more importance on student activity and interest in science instruction. Most teachers understood process-based assessment as a direction of free semester assessment and teachers mentioned positive aspects for students or teacher difficulties dependent on their perception on process-based assessment. Half of the teachers failed to implement student self-assessment and student peer-assessment due to subjectivity and complexity. Some teachers did not provide feedbacks to students due to a lack of time and did not use certain assessment methods due to a lack of knowledge of the assessment. Teachers who did not have an experience of discussions in a teacher learning community mentioned reasons regarding a small number of the same grade teachers and inactive attitude of colleagues. Teachers who did not participate in professional development programs mentioned a lack of teacher understanding of free semester, participation of the teacher in charge, and teacher choice of participation as reasons.

Safety and antifatigue effect of Korean Red Ginseng: a randomized, double-blind, and placebo-controlled clinical trial

  • Zhang, Li;Chen, Xiaoyun;Cheng, Yanqi;Chen, Qilong;Tan, Hongsheng;Son, Dongwook;Chang, Dongpill;Bian, Zhaoxiang;Fang, Hong;Xu, Hongxi
    • Journal of Ginseng Research
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    • v.43 no.4
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    • pp.676-683
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    • 2019
  • Background: Korean Red Ginseng (KRG) is widely used for strengthening the immune system and fighting fatigue, especially in people with deficiency syndrome. However, there is concern that the long-term application or a high dose of KRG can cause "fireness" (上火 in Chinese) because of its "dryness" (燥性 in Chinese). The aim of this study was to assess the safety and efficacy of a 4-week treatment with KRG in participants with deficiency syndrome. Methods: This was a 4-week, randomized, double-blind, placebo-controlled clinical trial. A total of 180 Chinese participants were randomly allocated to three groups: placebo control group, participants were given a placebo, 3.6 g/d; KRG 1.8 g and 3.6 g groups. The primary outcomes were the changes in fireness and safety evaluation (adverse events, laboratory tests, and electrocardiogram). The secondary outcomes were the efficacy of KRG on fatigue, which include the following: traditional Chinese medicine (TCM) symptom scale and fatigue self-assessment scale. Results: Of the 180 patients, 174 completed the full study. After 4 weeks of KRG treatment, the Fire-heat symptoms score including Excess fire-heat score and Deficient fire-heat score showed no significant change as compared with placebo treatment, and no clinically significant changes in any safety parameter were observed. Based on the TCM syndrome score and fatigue self-assessment score, TCM symptoms and fatigue were greatly improved after treatment with KRG, which showed a dose- and time-dependent effect. The total effective rate was also significantly increased in the KRG groups. Conclusion: Our study revealed that KRG has a potent antifatigue effect without significant adverse effects in people with deficiency syndrome. Although a larger sample size and longer treatment may be required for a more definite conclusion, this clinical trial is the first to disprove the common conception of "fireness" related to KRG.