• Journal of Internet Computing and Services
• /
• v.7 no.1
• /
• pp.39-47
• /
• 2006

The evaluation of MDx family hash functions such as MD5 is difficult because the design background or a generalized model is unknown. In this paper, an approximated model is proposed to generalize hash functions. The diffusion of a input difference is tested by an approximated model for MD5. The results show that MD5 does not provide perfect diffusion, so MD5 is weak against some attacks. We propose a multiple chaining pattern which provides perfect diffusion in approximated model of hash function without extra calculation or memory. And We show the probability of differential characteristics of our proposal.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 1999.05a
• /
• pp.385-388
• /
• 1999

A new local model for impact ionization coefficients is proposed to account for a non-local effect. New model uses an effective electric field which comes from the path integral of a tangent electric field at an arbitrary point. The model consists of local variables, such as doping concentration, carrier concentration and gradient of the field, and can be easily applied to a conventional drift-diffusion device simulator. By comparing the results with Monte Carlo simulation, it is confirmed that new model explains the non-local effect fairly well.

• Korean Journal of Cognitive Science
• /
• v.31 no.4
• /
• pp.103-136
• /
• 2020

This study compares the parafovea preview effect of adolescent group and adult group with different ages using eye tracking experiment. Also, this study confirms that the starting point parameter of the one boundary diffusion model can explain the data obtained through eye tracking experiments. In two experiments, parafoveal information processing was examined using the boundary technique. In Experiment 1, reading times were compared between the conditions given high frequency words preview versus masking preview. In Experiment 2, the condition in which low frequency words were given to parafovea preview information and the condition in which parafovea preview was masked were compared. We found that both the adolescent group and the adult group showed a parafovea preview effect. Also, first fixation, single fixation, and gaze duration of the two groups were different based on the word property shown in the parafovea. The first fixation data obtained in the two experiments were divided into quantiles and fitted into one boundary diffusion model. From the results, we argue that the parafovea preview information processing in the reading was described as the starting point parameter of the one boundary diffusion model.

• Health Policy and Management
• /
• v.18 no.4
• /
• pp.85-110
• /
• 2008

In this study, we explore the long-term demand forecasting of high-price medical equipments based on logistic and Bass diffusion model. We analyze the specific pattern of each equipment's diffusion curve by interpreting the parameter estimates of Bass diffusion model. Our findings are as follows. First, ultrasonic imaging system, CT are in the stage of maturity and so, the future demands of them are not too large. Second, medical image processing unit is between growth stage and maturity stage and so, the demand is expected to increase considerably for two or three years. Third, MRI is in the stage of take-off and Mammmography X-ray system is in the stage of maturity but, estimates of the potential number of adopters based on logistic model is considerably different to that based on Bass diffusion model. It means that additional data for these two equipments should be collected and analyzed to obtain the reliable estimates of their demands. Fourth, medical image processing unit have the largest q value. It means that the word-of-mouth effect is important in the diffusion of this equipment. Fifth, for MRI and Ultrasonic system, q/p values have the relatively large value. It means that collective power has an important role in adopting these two equipments.

• Spatial Information Research
• /
• v.18 no.4
• /
• pp.55-64
• /
• 2010

Since 2004, as Ubiquitous Information Technology that is new information technology paradigm has emerged, the necessity of government's role has been raised. In order to understand the government's role model for the effective use of the Ubiquitous Information Technology, this article closely analysed the process of the information policy in Korea. To accomplish these purpose the literature review and the exploratory research were used. The intent of this study was to analyze the government's role in the process of the information policy. Following are the major findings of this study. First. the government's role in driving the new information policy must be considered for the effective adopt and diffusion of the new information technology'. Second, three stages(adopt, diffusion, evaluation) are considered in the process of Korea information policy. Third, the revised government's role model is needed for the effective use of the new information technology in the future. In this study, I suggested the revised government's role model, that is consist of four stages. plan. adopt. diffusion, and performance and evaluation stage.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.12 no.3
• /
• pp.88-100
• /
• 2009

An inundation analysis was performed on Hwapocheon, one of the tributaries of Nakdong River, which was inundated by heavy rain in August, 2002 with overtopping and levee break. The results of the developed model, 2D diffusion wave inundation analysis model, was compared with inundation trace map as well as inundation depth in terms of time and maximum inundated area calculated from FLUMEN model for the assessment of model applicability. The results from the developed model showed high fitness of 88.61% in comparison with observed data. Also maximum inundated area and spatial distribution of inundation zone were also found to be consistent with the results of FLUMEN model. Therefore, inundation zone and maximum inundation area calculated over a period of time by adopting 2D diffusion wave inundation analysis model can be used as a database for identifying high risk areas of inundation and establishing flood damage reduction measures.

• Journal of Distribution Science
• /
• v.14 no.5
• /
• pp.71-80
• /
• 2016

Purpose - In case of automobile parts, there has been a lot of progress in the study on supplier development plans and SCM in industrial progress study as well as on the relationship between ERP and SCM. But supplier development program providers have researched on SCM performance in accordance with the interests of the supplier development program most, thus, buyers were knowledgeable about the earlier program performance. Therefore, the purpose of this study is to prove correlation factor, supplier factor, purchaser factor affecting SCM performance and ERP activating diffusion through the process of supplier development. Supplier development maturity formation model is considered important variables as mediators related to the procedure. Finally, the performance formation model of the supplier development maturity through supplier development factor would be presented as the outcome of this study. Research design, data, and methodology - Data gathering was as follows: questionnaires were delivered to 87 companies that have business connection with H Company. The empirical research to test our hypothesis was grounded on statistical analysis (adapting SPSS 19.0 & AMOS 19.0). The hypothesis is that the supplier development factor variables consist of correlation factor, supplier factor, purchaser factor, and have non-negative effects on the next variables: mediators such as supplier development maturity; and the supplier development maturity variables have a positive effect on the next variables: ERP activating diffusion, ERP activating diffusion has a non-negative effect on supply chain performance. We experimented the hypothesized model using path analysis with latent variables. Results - First, it was known that cooperation

, reliability

, comprehension on the purpose of SDP

, adaptation of change

, knowledge transfer program

, have significant positive effects on supplier development maturity. Second, supplier development maturity has positive effects significantly on ERP activating diffusion

. Finally, the causal relationships from ERP activating diffusion to SCM performance were significantly accepted. Its significance, as through the hypotheses, presented a structural model for the elaboration, suppliers develop maturity, and ultimately SCM performance that affect ERP leveraging spread beyond the concept of maturity of information system. Therefore, it was a mainstay of research on the existing ERP has they believed. Conclusion - First, with the fast changes in business circumstances, company should get the right information to implement SCM appropriately. For successful SCM, firms should understand the supplier development maturity formation and ERP activating diffusion. Second, supplier development factor has significant effects on supplier development maturity. Third, mediator such as supplier development maturity significantly affects ERP activating diffusion. Finally, ERP activating diffusion has significant impacts on SCM performance. This study makes a meaningful contribution to further appreciation on how supplier development maturity formation affects SCM performance. This study shows implications. First, there would not have been dealt with introducing the concept of supplier development maturity. Second, through empirical analysis and provider factors, the providers will develop the maturity that affect interactive factors between purchaser and supplier.

• Journal of Korea Multimedia Society
• /
• v.22 no.6
• /
• pp.684-694
• /
• 2019

Information spread in networks is universal in many real-world phenomena such as propagation of infectious diseases, diffusion of a new technology, computer virus/spam infection in the internet, and tweeting and retweeting of popular topics. The problem of finding the information source is to pick out the true source if information spread. It is of practical importance because harmful diffusion can be mitigated or even blocked e.g., by vaccinating human or installing security updates. This problem has been much studied, where it has been shown that the detection probability cannot be beyond 31% even for regular trees if the number of infected nodes is sufficiently large. In this paper, we study the impact of an anti-information spreading on the original information source detection. We consider an active defender in the network who spreads the anti-information against to the original information simultaneously and propose an inverse Voronoi partition based inference approach, called Voronoi Inference to find the source. We perform various simulations for the proposed method and obtain the detection probability that outperforms to the existing prior work.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.38 no.3
• /
• pp.51-70
• /
• 2013

This paper develops a model to predict the adoption and level of usage of network technology in a two-level supply chain with buyer-supplier relationships. A firm's adoption of a new technology depends not only on its own beliefs of the new technology's costs and benefits, but also on the adoption decisions of other firms in the supply chain. A model first analyzes an individual supplier's decision about a new technology adoption considering with multiple suppliers and buyers. Individual suppliers' decisions are aggregated with a population model to project how new technology diffuses across the supply chain and examine the pattern of diffusion process. This study found that as more firms adopt in initial periods, the total amount of information to the potential adopters in the population increases, and then the number of firms persuaded by the information increases as the process moves up the distribution of adoption process. We consider three factors influencing the diffusion speed of the new technology in a supply chain network : mean benefits, cost sharing, and information provision. This study examines how such factors affect the reduction of threshold levels, which implies that reductions in threshold levels have an aggregate effect by accelerating the rate of adoption. In particular, we explore relationship factors available in practice in a buyer-supplier relationship and numerically examines how these relationship factors contribute to increase the diffusion speed of the technology in a two-level supply chain.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.30B no.1
• /
• pp.90-98
• /
• 1993

A Gaussian is formed by diffusing a spot excitation. In this paper, a diffusion neural network model is derived from the diffusion equation. And it is shown that a difference of two Gaussians(DOG) may have the same shape as a Laplacian of Gaussian(LOG), A neural network model executing a DOG convolution by diffusing an external excitation is proposed. By this model intensity changes of image may be detected. This model may be implemented economically because each neuron has only four fixed-valued synapes.