• International Journal of Internet, Broadcasting and Communication
• /
• 제15권4호
• /
• pp.44-50
• /
• 2023

For Wi-Fi and IoT wireless systems, high-capacity wireless communication technology is being applied using MIMO OFDM. Because of virtu0al subcarriers in the practical MIMO OFDM system, the pilot subcarriers cannot be spaced equally. Thus, it is difficult to obtain a good mean square error (MSE) performance of the channel estimate. This paper proposes applicable methods and the newly discovered locations of pilot subcarriers in four transmitted antennas resulting in a good MSE performance with proposed optimization algorithms.

• International Journal of Contents
• /
• 제12권1호
• /
• pp.65-69
• /
• 2016

Wireless communication chipsets have fixed transmission rate and communication distance. Although there are many kinds of chipsets with throughput and distance purpose, they cannot support various types of wireless applications. This paper provides theoretic research results in order to support various wireless applications requiring different throughput, delayed quality-of-service (QoS), and different communication distances by using a wireless communication chipset with fixed rate and transmission power. As a performance metric, the probability for a data frame that successfully receives at a desired receiver is adopted. Based on this probability, the average number of transmission in order to make a successful frame transmission is derived. Equations are utilized to analyze the performance of a single-hop with channel coding and a dual-hop without error correction matter transmission system. Our results revealed that single-hop transmission assisted by channel coding could extend its communication distance. However, communication range extending effect of the single-hop system was limited. Accordingly, dual-hop transmission is needed to overcome the communication distance limit of a chipset.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2018년도 춘계학술대회
• /
• pp.549-552
• /
• 2018

LTE(Long Term Evolution)를 기반으로 한 LTE-R(LTE-Railway)은 철도통신기술의 하나로 열차운행에 필요한 각종 제어 신호 공급 및 다양한 통신 서비스 제공을 위해 활발하게 도입되고 있다. 본 논문에서는 LTE-R을 기반으로 하는 철도통신기술 및 서비스에 대하여 살펴보고, 철도통신과 관련한 국내 외 LTE-R 표준화 동향에 대해서 고찰한다. 본 연구 결과는 LTE-R 기반 철도통신의 연구 및 시스템 개발을 위한 기본 자료로 활용될 수 있다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 추계학술대회 논문집 전력기술부문
• /
• pp.111-113
• /
• 2006

Substation automation is one of the key issues for the enhancement of the power industrial foundation. IEC 60850 is an international standard specifying communication network and systems in substation. It supports interchangeability and interoperability of equipments from different vendors. ACSI(Abstract communication service interface) specifies basic communication structure for substation and IEDs. It supports communication as well as various services without proper protocols. For actual communication, MMS(Manufacturing Message Specification : ISO 9506) is used to map ACSI services. Solutions for the development of communication driver based don IEC 61850 are proposed in this paper.

• 인문언어
• /
• 제8집
• /
• pp.59-78
• /
• 2006

The paper brings to question how image as a medium is becoming a replacement for traditional letters in the modern culture. Reflection the importance of image in the context of modern society with the changes in the values of communication. The importance of letters in its traditional format as a book that signified not only the method of communication but also power for those who governed during the days of illiteracy in the past has changed, in the beginning with the development of printing and today with movies etc. that supply endless images instead of words as a means of communication. The images are the next generation in the method of communication and can be noted from the earliest civilizations such as Egypt where the method of communication was not words but drawings that depicted specific significations. The use of images for communication purposes in light of this fact suggests that images was being used before words in societies and its communicative values greater than that of words.

• International Journal of Internet, Broadcasting and Communication
• /
• 제5권1호
• /
• pp.18-22
• /
• 2013

We introduce, in this paper, a novel approach of protection mechanism for data which are transmitted not only between the networked devices but also between the digital media devices. As the devices are getting more powerful and more storage capacity, they can process the encoded/encrypted data autonomously. However, all devices must know the secret key that used to encrypt data, and also use secure method to distribute that key. Moreover, there are no protection mechanisms supporting end-to-end copy protection which result in the fact that the data passed through various devices can be manipulated or captured. Therefore, we propose a RFID-based key distribution and protection mechanism to resolve these problems.

• International Journal of Internet, Broadcasting and Communication
• /
• 제15권3호
• /
• pp.14-23
• /
• 2023

The cooperative communication systems using MIMO(multiple input multiple-output) relay are known as one of the most promising techniques to improve the performance and coverage of wireless communication systems. In this paper, we propose the cooperative communication systems using the relay with multi-antennas and DSTC(distributed space time coding) for decode-and-forward protocol. As using DSTC for DF(decode-and-forward), we can minimize the risk of error propagation at the wireless system using relay system. Also, the MIMO channel cab be formed by multi-antenna and DSTC at the MS(mobile station)-RS(relay station) and at the RS-BS(base station).Therefore, obtaining truly constructive the MIMO diversity and cooperative diversity gain from the proposed approach, the performance of system can be more improved than one of conventional system (relay with single antenna, no relay). The improvement in bit error rate is investigated through numerical analysis of the cooperative communication system with the proposed approach.

• 국제학술발표논문집
• /
• The 1th International Conference on Construction Engineering and Project Management
• /
• pp.974-979
• /
• 2005

Effective communication flow is a fundamental for the success of any construction projects. The key role of communications among project parties is even more critical in the case of Design-Build (DB) projects. Previous research has shown that these projects have an environment where integration between different project team members and schedule constraints increase channels of communication, and require faster communication flows. This paper summarizes the findings from research analyzing organizational structures and communication flow of the Texas State Highway 130 (SH130) project. Awarded in 2002, the SH130 project, totaling $1.3 billion USD, constitutes the "pilot" application for the DB approach in the state of Texas. A set of observations pertaining to team organization and communication issues in the design-build environment is included.

• 4차산업연구
• /
• 제1권2호
• /
• pp.21-32
• /
• 2021

Purpose - International diversification, a critical issue in research and practice, undoubtedly represents a growth strategy with great potential impact on firm performance. Although the literature has widely examined the relationship between international diversification and firm performance in international business and strategic management research, it remains unconfirmed. This study, therefore, aims to clarify the relationship as it relates to information service firms. Research design, data and methodology - To examine the international diversification-performance relationship, this study uses a sample of major Korean service firms spread over four industries spanning a period of five years between 2005 and 2009. In this study. generalized least square was used to analyze the relationship between international diversification and performance of service firms. Result - The result showed the U-shaped curvilinear form between international diversification and performance in service firms. Especially, IT service firms may differ from other service firms that the negative effect of internationality may have weaker than other types of service firm. Conclusion - Based on the empirical results, the U-shape relationship between international diversification and performance is confirmed in Korea service firms. Furthermore, information service firm may reduce the initial internationalization cost by transferring codified and digitized information using information and communication technology, so that gain benefit from early international expansion.

• 대한간호학회지
• /
• 제47권5호
• /
• pp.600-612
• /
• 2017

Purpose: This study aimed to identify and compare hospice care research topics between Korean and international nursing studies using text network analysis. Methods: The study was conducted in four steps: 1) collecting abstracts of relevant journal articles, 2) extracting and cleaning keywords (semantic morphemes) from the abstracts, 3) developing co-occurrence matrices and text-networks of keywords, and 4) analyzing network-related measures including degree centrality, closeness centrality, betweenness centrality, and clustering using the NetMiner program. Abstracts from 347 Korean and 1,926 international studies for the period of 1998-2016 were analyzed. Results: Between Korean and international studies, six of the most important core keywords-"hospice," "patient," "death," "RNs," "care," and "family"-were common, whereas "cancer" from Korean studies and "palliative care" from international studies ranked more highly. Keywords such as "attitude," "spirituality," "life," "effect," and "meaning" for Korean studies and "communication," "treatment," "USA," and "doctor" for international studies uniquely emerged as core keywords in recent studies (2011~2016). Five subtopic groups each were identified from Korean and international studies. Two common subtopics were "hospice palliative care and volunteers" and "cancer patients." Conclusion: For a better quality of hospice care in Korea, it is recommended that nursing researchers focus on study topics of patients with non-cancer disease, children and family, communication, and pain and symptom management.