• Journal of Information Technology Applications and Management
• /
• v.12 no.2
• /
• pp.145-161
• /
• 2005

In this paper, we present an experiment conducted to examine how the web site's architecture, content quantity and the user task complexity affect its usability. The experiment was performed in two phases on college students to visit existing web sites which are readily accessible via the Internet. The results of experiment show that the web site's architecture significantly affects the efficiency and the effectiveness interactively with its content quantity and the user task's complexity. On the other hand, none of the above three factors show significant effects on the satisfaction and the learnability. In particular, the web site's content quantity does not have any statistically significant effects on the satisfaction and the learnability. It implies that the factors affecting the satisfaction and the learnability are different from those affecting the efficiency and the effectiveness. The analysis reassures that it is essential to consider the context of use in designing a web site.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 1999.06a
• /
• pp.171-176
• /
• 1999

Template matching is one of the most often used techniques for machine vision applications to find a template of size M$\times$M or subimage in a scene image of size N$\times$N. Most template matching methods, however, require pixel operations between the template and the image under analysis resulting in high computational cost of O(M2N2). So in this thesis, we present a two stage template matching method. In the first stage, we use a novel low cost feature whose complexity is approaching O(N2) to select matching candidates. In the second stage, we use conventional template matching method to find out the exact matching point. We compare the result with other methods in terms of complexity, efficiency and performance. Proposed method was proved to have constant time complexity and to be quite invariant to noise.

• Journal of the Korea Society of Computer and Information
• /
• v.23 no.1
• /
• pp.57-66
• /
• 2018

It is known that a single-key and a related-key attacks on AES-128 are possible for at most 7 and 8 rounds, respectively. The security of CMAC, a typical block-cipher-based MAC algorithm, has very high possibility of inheriting the security of the underlying block cipher. Since the attacks on the underlying block cipher can be applied directly to the first block of CMAC, the current security margin is not sufficient compared to what the designers of AES claimed. In this paper, we consider HMAC-DM-AES-128 as an alternative to CMAC-AES-128 and analyze its security for reduced rounds of AES-128. For 2-round AES-128, HMAC-DM-AES-128 requires the precomputation phase time complexity of $2^{97}$ AES, the online phase time complexity of $2^{98.68}$ AES and the data complexity of $2^{98}$ blocks. Our work is meaningful in the point that it is the first security analysis of MAC based on hash modes of AES.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2009.04a
• /
• pp.523-526
• /
• 2009

시계열 데이터에서 패턴을 분석하는 기법은 많은 발전이 이루어져 오고 있으나 주식시장의 경우 패턴 분석 및 예측에 관련되어 많은 연구가 이루어져 있지 않고 있다. 이는 주가의 등락 자체가 본질적으로 무작위하다고 생각되어지고 있기 때문이다. 본 연구에서는 주가의 등락이 보여주는 무작위성의 정도를 Kolmogorov Complexity로 측정, 그 무작위성의 정도와 본 논문에서 제시한 반전역정렬로 예측하는 주가의 예측 간의 상관관계를 보인다. 이를 위하여 KOSPI 주식 데이터 28년 690개의 데이터를 수집하여 이들 주식 데이터의 등락을 양자화된 문자열로 변환하여 본 논문에서 제시한 방법의 의미를 평가하였다. 그 결과 Kolmogorov Complexity가 높은 경우에는 주가 변동 예측이 어려우며, Kolmogorov Complexity가 낮은 경우에는 주식 변동 예측은 가능하나 등락 예측 율은 단기 예측은 12%이상의 예측율을 보일 수 없으며, 장기 예측의 경우 54%의 예측율로 수렴함을 확인하였다.

• East Asian mathematical journal
• /
• v.25 no.1
• /
• pp.55-68
• /
• 2009

In this paper we propose new large-update primal-dual inte-rior point algorithms for $P_*(\kappa)$ linear complementarity problems(LCPs). New search directions and proximity measures are proposed based on the kernel function$\psi(t)=\frac{t^{p+1}-1}{p+1}+\frac{e^{\frac{1}{t}}-e}{e}$,$p{\in}$[0,1]. We showed that if a strictly feasible starting point is available, then the algorithm has $O((1+2\kappa)(logn)^{2}n^{\frac{1}{p+1}}log\frac{n}{\varepsilon}$ complexity bound.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.14 no.4
• /
• pp.1579-1602
• /
• 2020

In the design of production system, buffer capacity allocation is a major step. Through polymorphism analysis of production capacity and production capability, this paper investigates a buffer allocation optimization problem aiming at the multi-stage production line including unreliable machines, which is concerned with maximizing the system theoretical production rate and minimizing the system state entropy for a certain amount of buffers simultaneously. Stochastic process analysis is employed to establish Markov models for repairable modular machines. Considering the complex structure, an improved vector UGF (Universal Generating Function) technique and composition operators are introduced to construct the system model. Then the measures to assess the system's multi-state reliability and structural complexity are given. Based on system theoretical production rate and system state entropy, mathematical model for buffer capacity optimization is built and optimized by a specific genetic algorithm. The feasibility and effectiveness of the proposed method is verified by an application of an engine head production line.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.35 no.3
• /
• pp.50-61
• /
• 2007

The purpose of this study is to establish design guidelines for waterscape facilities of healing gardens in psychiatric hospitals. Data were collected through simulation and interview. The subjects included schizophrenic (n=42) and alcoholic (n=41) inpatients as well as medical staff personnel (n=40) at Maeumsarang Hospital. The results of this study are as follows: It was revealed that for all three groups the first preference was a natural flowing waterscape, and the second preference was a natural descending waterscape. The schizophrenic subjects had a greater preference for a static artificial waterscape and a descending artificial multistory waterscape than the other two groups. The alcoholic subjects preferred an ascending natural multistory waterscape. The analysis on the preference towards an ascending type and a descending type from the perspective of naturalness and complexity. Complexity had a greater influence than naturalness in the ascending waterscapes, and naturalness had more influence than complexity in the descending style waterscapes. Therefore, these factors need to be taken into consideration when designing either ascending or descending waterscape facilities. In general, the subjects preferred natural, dynamic and descending waterscapes to the artificial, static and ascending variety.

• Journal of Korea Trade
• /
• v.25 no.7
• /
• pp.41-55
• /
• 2021

Purpose - This paper empirically investigates the relationship between the Economic Complexity Index (ECI) and the level of development. Moreover, this research attempts to discover the determinants of ECI in the globalization wave. Design/methodology - Our empirical model considers the relationship between ECI and the level of development in middle- and high-income economies from 1995 to 2010 by using systemic qualitative analysis, including OLS, fixed-effects, and system GMM. Next, this research used OLS regression to find the determinants of ECI. In particular, we compared the effects of different factors on ECI in the different development stages. Findings - Our main findings can be summarized as follows: 1. If the ECI increases by 1, it could lead to an increase of about 30% in the level of development in middle- and high-income economies. 2. Human capital plays an important role in the development of and increase in ECI. 3. GVC participation and outflow FDI enhance an increase in ECI, in particular in middle-income economies. 4. The development of manufacturing industries is helpful to increase ECI; however, middle-income economies should pay more attention to their comparative advantage industries. 5. R&D has positive effects on the ECI. Originality/value - To the best of our knowledge, this is the first paper that uses systemic qualitative analysis to investigate the relationship between ECI and the level of development. The paper provides suggestions for policy makers to increase ECI under the current wave of globalization, in particular in middle-income economies.

• IE interfaces
• /
• v.8 no.1
• /
• pp.61-78
• /
• 1995

Warehouse planning or design is not a static, one-time activity. To survive in the constantly changing market warehouse design should be a continuous process in which the anticipated requirment are reflected on the current warehouse status. Thus, the goal of warehouse management is to effectively utilize the various warehouse resources to meet the varying customer requirment. This paper presents an engineering framework for warehousing system analysis and design from the perspective of a total system approach. The complexity pertinent to warehousing system analysis and design is first discussed, which mainly come from the interplay among product data, order data, equipment types, operating strategies, and functional specification of the overall system. The understanding of the complexity leads to a general structure and a conceptual design procedure for a warehousing system. The general structure is comprehensive enough to represent most warehousing and flexible enough to accommodate the more sophisticated ones. The conceptual design procedure portrays the high-level interelationships the design issues.

• Journal of the Korean Society for Railway
• /
• v.12 no.5
• /
• pp.744-750
• /
• 2009

According to the result of related studies, the degradation of human performance has been revealed as one of the most significant causes resulting in the safety of any human-involved system. This means that preventing the occurrence of accidents/incidents through avoiding the degradation of human performance is prerequisite for their successive operation. To this end, it is necessary to develop a plausible tool to evaluate the complexity of a task, which has been known as one of the decisive factors affecting the human performance. For this reason, in this paper, the complexity of tasks to be conducted by KTX drivers was quantified by TACOM measure that is enable to quantify the complexity of proceduralized tasks being used in nuclear power plants. After that, TACOM scores about the tasks of KTX drivers were compared with NASA-TLX scores that are responsible for the level of a subjective workload to be felt by KTX drivers.