• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.2C
• /
• pp.181-188
• /
• 2007

This paper proposed a watermark embedding/extracting method using CABAC(Context-based Adaptive Binary Arithmetic Coding) which is the entropy encoder for the main profile of MPEG-4 Part 10 H.264/AVC. This algorithm selects the blocks and the coefficients in a block on the bases of the contexts extracted from the relationship to the adjacent blocks and coefficients. A watermark bit is embedded without any modification of coefficient or with replacing the LSB(Least Significant Bit) of the coefficient with a watermark bit by considering both the absolute value of the selected coefficient and the watermark bit. Therefore, it makes it hard for an attacker to find out the watermarked locations. By selecting a few coefficients near the DC coefficient according to the contexts, this algorithm satisfies the robustness requirement. From the results from experiments with various kinds and various strengths of attacks the maximum error ratio of the extracted watermark was 5.02% in maximum, which makes certain that the proposed algorithm has very high level of robustness. Because it embeds the watermark during the context modeling and binarization process of CABAC, the additional amount of calculation for locating and selecting the coefficients to embed watermark is very small. Consequently, it is highly expected that it is very useful in the application area that the video must be compressed right after acquisition.

• Journal of Information Processing Systems
• /
• v.5 no.4
• /
• pp.175-186
• /
• 2009

Power consumed by modern computer systems, particularly servers in data centers has almost reached an unacceptable level. However, their energy consumption is often not justifiable when their utilization is considered; that is, they tend to consume more energy than needed for their computing related jobs. Task scheduling in distributed computing systems (DCSs) can play a crucial role in increasing utilization; this will lead to the reduction in energy consumption. In this paper, we address the problem of scheduling precedence-constrained parallel applications in DCSs, and present two energy- conscious scheduling algorithms. Our scheduling algorithms adopt dynamic voltage and frequency scaling (DVFS) to minimize energy consumption. DVFS, as an efficient power management technology, has been increasingly integrated into many recent commodity processors. DVFS enables these processors to operate with different voltage supply levels at the expense of sacrificing clock frequencies. In the context of scheduling, this multiple voltage facility implies that there is a trade-off between the quality of schedules and energy consumption. Our algorithms effectively balance these two performance goals using a novel objective function and its variant, which take into account both goals; this claim is verified by the results obtained from our extensive comparative evaluation study.

• The Journal of Korean Association of Computer Education
• /
• v.4 no.1
• /
• pp.109-118
• /
• 2001

The change of job environments with information technologies demands workers' capabilities to adapt rapidly changing and variety of work environments. To cope with this situation, many countries and institutions propose 'basic vocational competency' which is focused on basic capabilities of workers. And also, they do research on how to educate and train students to be prepared for new environments. We surveyed with teachers of computer technology which is one of the information technologies, to find out the competency development level, they expressed negative view on general competency development because of current computer education's focusing on 'using computers to process information'. Therefore, we intended to analyze the necessity and problem of developing the whole basic vocational competency in vocational high school and proposed a 'in context' learning for it.

• Journal of The Korean Association For Science Education
• /
• v.24 no.4
• /
• pp.687-708
• /
• 2004

The purpose of this study is to investigate the relationships between cognitive conflict and students' causal attributions and to find out what kinds of attributions affect successful resolution of cognitive conflict in learning physics. Twenty-nine college students who attended a base general physics course took an attribution test and a conceptual pretest related to action and reaction concept. Of these, twenty students who revealed alternative conceptions were selected. They were confronted with a discrepant demonstration and took part in the cognitive conflict level test, a posttest, and delayed posttest. Those students who experienced high levels of cognitive conflict were selected and interviewed to find out what kinds of attributions affect resolving the conflict. When confronted with the discrepant event, the students who attributed success outcomes to "effort" experienced higher levels of cognitive conflict than those to "task difficulty." However, those students who revealed high levels of cognitive conflict and attributed success outcomes to effort did not always produce conceptual change. They had different perspectives on effort and conducted different effort activities to resolve the cognitive conflict. In addition, these effort activities appeared to include their motivational beliefs, metacognitive and volitional strategies. The results of this study indicate that in order for the conflicts to lead to change, students need to have the perspective on effort implying the use of the self-regulated learning strategy and to conduct effort activities based on them. Beyond cold conceptual change, this article suggests that there is a management strategy of cognitive conflict in the classroom context.

• The Mathematical Education
• /
• v.49 no.4
• /
• pp.501-522
• /
• 2010

In this study, 'Instruments of the achievement attribution in mathematical learning' was develop to investigate the reasons of mathematical learning achievement by reflecting Korean middle school and high school students' psychological characters and learning context in mathematical learning. To develop the appropriate items for the achievement attribution in mathematical learning, after reviewing attribution literature thoroughly, first version of the instrument was developed and Exploratory Factor Analysis and Confirmatory Factor Analysis were conducted. Then, to reduce the effect of the gender difference and achievement level difference, Differential Item Functioning was performed. Also, using Multiple group Confirmatory Factor Analysis, this instrument was investigated to see whether this can be used for both middle school and high school. The final items for success attribution are 3 items for luck, 3 items for effort, 2 items for ability. The failure attribution were composed of 3 items for luck, 3 items for effort, 2 items for ability, and 2 items for other. The instrument was developed by using large samples and psychometric analysis. Therefore, mathematic teachers can use this instrument efficiently to make a foundation for better learning environment so students' cognitive area and affective area can be harmonized.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.10
• /
• pp.4933-4956
• /
• 2016

Use-After-Free (UAF) is a common lethal form of software vulnerability. By using tools such as Web Browser Fuzzing, a large amount of samples containing UAF vulnerabilities can be generated. To evaluate the threat level of vulnerability or to patch the vulnerabilities, automatic deduplication and exploitability determination should be carried out for these samples. There are some problems existing in current methods, including inadequate pertinence, lack of depth and precision of analysis, high time cost, and low accuracy. In this paper, in terms of key dangling pointer and crash context, we analyze four properties of similar samples of UAF vulnerability, explore the method of extracting and calculate clustering eigenvalues from these samples, perform clustering by fast search and find of density peaks on a large number of vulnerability samples. Samples were divided into different UAF vulnerability categories according to the clustering results, and the exploitability of these UAF vulnerabilities was determined by observing the shape of class cluster. Experimental results showed that the approach was applicable to the deduplication and exploitability determination of a large amount of UAF vulnerability samples, with high accuracy and low performance cost.

• East Asian Journal of Business Economics (EAJBE)
• /
• v.9 no.3
• /
• pp.1-13
• /
• 2021

Purpose - For many Vietnamese students, the national high school graduation examination is one of the most important exams in their lives, transitioning from high school to tertiary education. Considering that the national examination is exceptionally important for admission of higher education, failure of management system and educational inequalities lead to serious academic concerns. By using the concept of justice and motivation, the current study aimed to explore the effects of justice dimensions and motivation on student satisfaction in the context of education, specifically focusing on the national examination for higher education. Research design, data and methodology - In this regard, this study proposed a conceptual model and conducted an online survey to test relevant hypotheses. Result - The empirical findings of the study found that procedural, distributive justice, and intrinsic motivation affected the level of student satisfaction. The results found that distributive and procedural justice and intrinsic motivation showed significant on satisfaction. Conclusion - The results of this study would be useful for policymakers to make more informed choices and also suggest further programs and projects of the Vietnamese government, aiming to develop the system of university admissions in the future. This study suggests that adoption of better management system and policies will significantly affect academic satisfaction and higher education environment.

• Safety and Health at Work
• /
• v.13 no.2
• /
• pp.187-191
• /
• 2022

Background: Traffic injuries have become a significant public health problem in low- and middle-income countries. Several studies have examined the role of personality and attitude toward traffic safety in predicting driving behaviors in diverse types of drivers. Few studies have investigated risky behavior among public passenger van drivers. This study aims to identify the predictors of self-reported risky driving behavior among public van drivers. Method: A total of 410 public van drivers were interviewed at terminal stations in Bangkok. Hierarchical regression models were applied to determine the effects of demographics, personality traits, and attitude on self-reported risky driving behaviors. Results: The results indicated that drivers with a high education level, more working days, and high scores for normlessness and anger were more likely to report risky driving behaviors (p < 0.05). Conclusion: The personality traits and attitude toward speeding account for aberrant self-reported risky driving behavior in passenger van drivers. This could be another empirical basis for evidence-based road safety interventions in the context of public transport.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.19 no.4
• /
• pp.87-96
• /
• 2023

ChatGPT, a leader in generative AI, can use natural expressions like humans based on large-scale language models (LLM). The ability to grasp the context of the language and provide more specific answers by algorithms is excellent. It also has high-quality conversation capabilities that have significantly developed from past Chatbot services to the level of human conversation. In addition, it is expected to change the operation method of the tourism industry and improve the service by utilizing ChatGPT, a generative AI in the tourism sector. This study was conducted to explore ChatGPT trends and paradigms in tourism. The results of the study are as follows. First, keywords such as tourism, utilization, creation, technology, service, travel, holding, education, development, news, digital, future, and chatbot were widespread. Second, unlike other keywords, service, education, and Mokpo City data confirmed the results of a high degree of centrality. Third, due to CONCOR analysis, eight keyword clusters highly relevant to ChatGPT in the tourism sector emerged.

• Journal of Korean Society for Atmospheric Environment
• /
• v.29 no.3
• /
• pp.275-286
• /
• 2013

It is well known that exposure to high level of PM (particulate matter) can adversely affect human health. However, little is known about health burden of PM considering the relationship, exposed level of PM, and health level in local communities. And, there is scarcely methodical assessment of uncertainty for application to policies of these assessment results. The scope of this study is divided into two parts: firstly to estimate the death burden of PM10 (particulate matter less then $10{\mu}m$ in diameter) in Seoul metropolitan region, and secondly to evaluate potential uncertainties in these estimates. To estimate the death burden of PM10 in Seoul metropolitan region from 2005~2010, we firstly assessed the relationship between daily mean PM10 and daily death counts in Seoul from 2000~2010, and calculated the death burden of PM10 using BenMAP (Environmental Benefits Mapping and Analysis Program). After that, we identified and characterized uncertainties to substantially influence the results of death burden. The daily mortality risk was increased 1.000227 times (p-value/0.001) associated with $1{\mu}g/m^3$ increase of daily mean PM10 for all ages population, Seoul. And, death burdens of PM10 in Seoul metropolitan region were estimated from 5.51 in 2005 to 5.12 in 2010 per 100,000 people. Finally, we categorized context, model, and input uncertainty and characterized these uncertainties in three dimensions (i.e. location, level, and nature) using uncertainty typology. In our study, we argue that uncertainties need to be identified, assessed, reported and interpreted in order for assessment results to adequately support decision making, such as the establishment of air quality standards based on health burden of air quality.