• Journal of Ubiquitous Convergence Technology
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• 제2권1호
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• pp.51-55
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• 2008

A digital home is a ubiquitous environment that is expected to be realized in the near future. All information appliances in a house are connected to each other through wired and/or wireless home networks. Authenticated user can access the various services provided by the digital home, and the access is not restricted by equipment, time, or location. The technologies that form the digital home can be grouped into two categories: wired networking technologies and wireless networking technologies. For the purpose of ubiquitous environments, wireless-networks offer suitable and seamless high-quality services. A wireless LAN can be created simply by equipping a single access point. For that reason, the cost of establishing such a network is low and using it is easy. Of course, there is an exciting new wireless technology. It is the Ultra Wide Band (UWB). However, it is not enough to bring wireless convenience, although offering a broad range of high-speed data transfer capabilities, Because of unstable. Thus, of the wireless-networking systems, we focus on the wireless LAN. We quantitatively analyze its capabilities. The dynamic and adaptive wireless LAN provides a foundation for the evolution toward the next generation of wireless and adaptive networks. The difference between wired LAN and wireless LAN in upload and download rates is small. Although the wireless LAN experiences a greater loss rate than the wired LAN, the difference is minimal. We conclude that a wireless LAN is suitable for use in an apartment environment.

• 대한가정학회지
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• 제46권10호
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• pp.97-106
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• 2008

We examined the effects of family and home literacy environments on the vocabulary and reading abilities of 3 to 5-year-olds. In particular, SES was considered against home literacy environment. The sample consisted of 366 Korean children and their mothers. We found that the level of mother's education was related to the child's vocabulary test score. After controlling for family factors, home literacy environment score positively predicted children's performance both in vocabulary and reading tests. Magnitudes of differences between the two literacy groups (high and low home literacy environment) became larger in the children from relative lower income families. Magnitudes of differences for vocabulary and reading tests was strikingly large in the low-income group both in vocabulary and reading tests. These findings shed lights on the importance of parent education and family services for low-income families with preschool children.

• 대한조선학회논문집
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• 제45권3호
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• pp.329-336
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• 2008

Basic performances of wireless sensor network (WSN) and power line communication (PLC) confirmed in the test bed ashore are investigated in the 3000-ton class training ship of Korea Maritime University. The ubiquitous technologies can be considered for the provision of safety and convenience in a ship. We employed WSN and PLC, as the ubiquitous technologies, at the two areas within the training ship to estimate the realization of the ubiquitous environments in a ship. The experiments show rather good results in terms of data transfer rate. However, more detailed studies concerning the connection between WSN and PLC, noises induced to power line and fading effects are required to improve the quality and the stability of the communication for the ubiquitous environments.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권9호
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• pp.1684-1697
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• 2011

We show that two protocols for RFID mutual authentication in pervasive computing environments, recently proposed by Kang et al, are vulnerable to several attacks. First, we show these protocols do not preserve the privacy of users' location. Once a tag is authenticated successfully, we show several scenarios where legitimate or illegitimate readers can trace the location of that tag without any further information about the tag's identifier or initial private key. Second, since the communication between readers and the database takes place over an insecure communication channel and in the plaintext form, we show scenarios where a compromised tag can gain access to confidential information that the tag is not supposed get access to. Finally, we show that these protocols are also vulnerable to the replay and denial-of-service attacks. While some of these attacks are due to simple flaws and can be easily fixed, others are more fundamental and are due to relaxing widely accepted assumptions in the literature. We examine this issue, apply countermeasures, and re-evaluate the protocols overhead after taking these countermeasures into account and compare them to other work in the literature.

• 한국지능시스템학회논문지
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• 제20권4호
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• pp.489-496
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• 2010

본 논문은 3D 환경에서의 스웜시스템을 위한 자기조직화 방법을 제시한다. 스웜 시스템의 자기조직화를 위하여 인력과 척력을 이용하는 인공 포텐셜 함수(Artificial Potential Function, 이하 APF)를 사용하였다. 제안된 연구에서는 2D 환경에서 자기조직화를 위해 사용되어왔던 다양한 포텐셜들을 3D 환경에 맞게 확장 설계한다. 지면이나 수면 등의 경계면을 가지는 3D 환경의 특성을 고려하여 지면 포텐셜(Ground Potential)을 제안한다. 지면 포텐셜을 고려하지 않았을 때와 고려할 때의 비교 결과를 통해 지면 포텐셜의 필요성과 효과를 보여준다. 마지막으로, 다양한 시뮬레이션 결과를 통해 3D 환경에서 확장된 인공포텐셜과 그 성질의 효율성을 보여준다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권5호
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• pp.2299-2318
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• 2019

Location-aware networks are of great importance for both civil lives and military applications. Methods based on line-of-sight (LOS) measurements suffer sever performance loss in harsh environments such as indoor scenarios, where sensors can receive both LOS and non-line-of-sight (NLOS) measurements. In this paper, we propose a data association (DA) process based on the expectation maximization (EM) algorithm, which enables us to exploit multipath components (MPCs). By setting the mapping relationship between the measurements and scatters as a latent variable, coefficients of the Gaussian mixture model are estimated. Moreover, considering the misalignment of sensor position, we propose a space-alternating generalized expectation maximization (SAGE)-based algorithms to jointly update the target localization and sensor position information. A two dimensional (2-D) circularly symmetric Gaussian distribution is employed to approximate the probability density function of the sensor's position uncertainty via the minimization of the Kullback-Leibler divergence (KLD), which enables us to calculate the expectation step with low computational complexity. Moreover, a distributed implementation is derived based on the average consensus method to improve the scalability of the proposed algorithm. Simulation results demonstrate that the proposed centralized and distributed algorithms can perform close to the Monte Carlo-based method with much lower communication overhead and computational complexity.

• 말소리와 음성과학
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• 제15권3호
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• pp.83-88
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• 2023

This study investigates the fine-tuning of large-scale Automatic Speech Recognition (ASR) models, specifically OpenAI's Whisper model, for domain-specific applications using the KsponSpeech dataset. The primary research questions address the effectiveness of targeted lexical item emphasis during fine-tuning, its impact on domain-specific performance, and whether the fine-tuned model can maintain generalization capabilities across different languages and environments. Experiments were conducted using two fine-tuning datasets: Set A, a small subset emphasizing specific lexical items, and Set B, consisting of the entire KsponSpeech dataset. Results showed that fine-tuning with targeted lexical items increased recognition accuracy and improved domain-specific performance, with generalization capabilities maintained when fine-tuned with a smaller dataset. For noisier environments, a trade-off between specificity and generalization capabilities was observed. This study highlights the potential of fine-tuning using minimal domain-specific data to achieve satisfactory results, emphasizing the importance of balancing specialization and generalization for ASR models. Future research could explore different fine-tuning strategies and novel technologies such as prompting to further enhance large-scale ASR models' domain-specific performance.

• 인터넷정보학회논문지
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• 제7권3호
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• pp.61-69
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• 2006

이동통신 단말기와 중앙 서버에 각각 저장되어 있는 자료에 대한 동기화는, 효율적인 이동통신 환경에서는 반드시 필요한 작업이다. 그러나, 이동통신 단말기 제조회사들은 각기 고유의 자료 동기화 방식을 사용하고 있기 때문에, 제조회사가 다른 단말기들 간의 자료에 대한 상호 운용을 보장할 수 없다. 따라서, OMA(Open Mobile Alliance)가 공개 표준안인 SyncML 자료 동기화 방식을 제안하였다. 본 논문에서는, ActiveSync 자료 동기화 방식도 함께 처리할 수 있는 SyncML 기반의 자료 동기화 게이트웨이 시스템을 설계 구현하였다. 즉, ActiveSync 방식의 자료를 SyncML 방식의 자료로 변환하는 통합 자료 동기화 게이트웨이 시스템을 구현함으로써, 2 가지 서로 다른 자료 동기화 방식의 단말기들 간의 상호 운용을 가능하게 하였다. 또한, ActiveSync 기반 이동통신 단말기와 SyncML 기반 중앙 서버간의 이동통신 실험을 통해, 본 논문에서 구현한 자료 동기화 게이트웨이가 정상적으로 동작함을 확인하였다.

• 한국의상디자인학회지
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• 제16권3호
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• pp.191-200
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• 2014

Employees overseas have a need to prepare according to the different environments and industrial structures between countries. Therefore, to investigate qualities for fashion designers to possess when they work abroad, especially in the United States, this study compared the level of knowledge required to fulfill the work of fashion design in both South Korea and the United States. Responses from workers who are engaged to fashion design from the representative online career information systems of two countries, 'Worknet' in South Korea and '$O^*Net$' in the United States, were used as data. Looking at the result derived from the analysis of this study, first by comparing various statistical indicators, results showed the difference between knowledge level required to fashion designer in South Korea and in the United States. Even with the same type of job, because environments and industrial structures of each country are dissimilar, a different level of knowledge will be required in order to perform their tasks. Second, fashion designers in both South Korea and the United States required a high level of knowledge in the 'fine arts', 'administration and management', 'production and processing', and 'design' to perform their duties as a fashion designer. As a result, both countries have similarities that fashion designers need to possess a high level of the knowledge in areas such as 'production of products' as well as 'sales of products'. Furthermore, human relationship field of knowledge such as 'counseling', 'psychology', and 'communication' appeared to be more necessary to fashion designers in South Korea than those in the United States. On the other hand, higher degree of knowledge of 'machines and tools', ' fine arts', and 'transportation' appeared to be more necessary to fashion designers in the United States than those in South Korea.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제3권1호
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• pp.7-18
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• 2014

비행 소프트웨어는 인공위성의 탑재 컴퓨터에서 사용되는 소프트웨어로, 실시간성과 고신뢰성이 요구된다. 이와 같은 요구사항으로 인해 비행 소프트웨어는 동작 환경에 대한 종속성을 갖게 된다. 이러한 문제는 새로운 시스템을 구축할 때마다 매번 다시 개발하여야 하는 상황을 초래한다. 따라서 비행 소프트웨어와 동작 환경 사이의 종속성을 제거할 필요가 있으며, 이는 비행 소프트웨어의 이식성 향상을 통해 달성할 수 있다. 본 논문에서는 이를 위해 IMA 아키텍처 기반의 플랫폼 아키텍처를 제안한다. 이 아키텍처는 이식성을 극대화하기 위해 두 가지의 IMA 아키텍처 실현 방안을 기반으로 구축된 혼합형 아키텍처이다. 또한 혼합형 아키텍처의 검증을 위해 혼합형 아키텍처 기반의 시스템을 구현하고 동작 결과를 분석한다. 본 논문에서 제안한 아키텍처를 통해서 비행 소프트웨어와 동직 환경 사이의 종속성을 제거할 수 있다. G망을 활용하여 끊김없는 서비스를 지원할 수 있는 방안을 제안하였으며, 테스트베드 구현을 통하여 제안 방안의 우수성을 검증하였다.