• 한국정보통신학회논문지
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• 제19권3호
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• pp.741-746
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• 2015

최근 모바일 운영체제 시장이 확대됨과 동시에 반도체 및 무선통신의 발달로 안드로이드 운영체제가 탑재된 각종 스마트폰 및 에어컨, 스마트TV, 청소로봇, 카메라 등 그 수가 빠른 속도로 보급되고 있다. 이로 인해, 일상생활에서 사용하는 다양한 제품들을 네트워크로 연결하여 정보수집이 가능하게 되었다. 그러나 여러 기기들을 한 번에 제어하는 방법이 아닌, 한 기기의 제어를 한 애플리케이션이 담당하는 형태가 대부분이고, 하나의 디바이스에서 모든 기기들을 관리할 수 있는 애플리케이션이 부족한 실정이다. 이에 따라, 본 논문에서는 유무선 공유기(AP)에 안드로이드 운영체제를 기반으로 하는 기기들을 등록시키고, 서버에 등록되어있는 기기를 웹으로 관리, 제어할 수 있는 시스템을 설계 및 구현하였다. 이는 현재 연구가 활발히 진행 중인 IoT(Internet of Things)분야에 널리 활용될 것으로 사료된다.

• 한국정보통신학회논문지
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• 제22권9호
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• pp.1243-1249
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• 2018

본 논문에서는 IEEE 802.15.4 슬롯 기반 CSMA/CA(Slotted Carrier Sense Multiple Access with Collision Avoidance) 네트워크에서 시스템 처리율 향상을 위해 동작 중인 단말 수 추정을 통한 백오프 기간 튜닝 기법을 제안한다. IEEE 802.15.4 슬롯 기반 CSMA/CA 네트워크에서는 각 단말이 채널을 항상 센싱하지는 않으므로, 제안하는 기법에서는 채널을 항상 센싱할 수 있는 PAN(Personal Area Network) 코디네이터를 사용하여 동작 중인 단말 수를 추정한다. 이 때, 실시간 단말 수 추정을 위해 단순 이동 평균 필터를 사용한다. PAN 코디네이터는 추정한 단말 수에 따라 튜닝한 최적의 백오프 기간을 비콘 프레임에 담아 PAN 코디네이터에 연결된 단말들에게 전달한다. 시뮬레이션을 통해 제안하는 기법의 단말 수 추정에 대한 성능과 시스템 처리율에 대한 성능을 평가한다. 시뮬레이션 결과를 통해 제안하는 기법이 IEEE 802.15.4 표준보다 더 높은 시스템 처리율을 얻을 수 있음을 보인다.

• 한국콘텐츠학회논문지
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• 제10권4호
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• pp.91-97
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• 2010

Web 2.0 시대를 맞아 최근 웹상에는 소셜 미디어 서비스(Social Media Service)가 각광받고 있다. 환경적 변화에 맞춰 사용자의 요구를 충족시키는 소셜 미디어 서비스로써 합주서비스를 제공하고자 한다. 합주서비스는 MMMD(Multi Media Multi Device) 개념으로 음원을 제공하고자 한다. 즉, 합주곡을 하나의 재생장치를 통해 듣는 것이 아니라, 악기 별로 재생장치를 선택해 연주함으로써 오케스트라에서 음악을 감상하는 것 같은 실감을 부여할 수 있다. 목표를 충족시키기 위해서 합주곡을 구성하는 악기 별 음원을 분리하고 연주를 위해 필요한 음원을 추출하고 음원을 각 재생장치로 전달하는 작업을 AET Process로 정의하였다. 음원 간의 동기화를 제어하기 위해서 쉼표를 이용한 동기화 알고리즘을 제안하였다. AET Process와 쉼표를 이용한 동기화 처리 방법을 이용하여 사용자에게 실감 있는 합주 서비스를 제공할 수 있다.

• 대한인간공학회지
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• 제31권1호
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• pp.41-48
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• 2012

Objective: Companies want to expand their business by providing their services at other devices and new services based upon existing services. Therefore, they look for building brand identity by providing same experience throughout devices and services. Background: Many services are available to use at multiple devices including mobile phones, tablet, personal computers, and televisions, thanks to proliferation of n-screen and cloud technology. Method: It was discussed that consistency, which emphasizes the regularity and has been one of essential aspects of user interface design, seems not effective to be applied to n-screen services, owing to different screen size, input and output peripherals, usage environment and users' attitude. Results: A new definition of same experience among different devices and services, called coherence, was introduced and abstraction levels of user interfaces were proposed as the denominator of defining coherence. Then types of users' task knowledge at each abstraction level were discussed with examples. Conclusion: This paper concluded by discussing design requirements for designing coherent user interfaces among devices and services.

• ETRI Journal
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• 제39권4호
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• pp.546-557
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• 2017

In a long term evolution-advanced (LTE-A) system, the traffic overload of machine type communication devices is a challenge because too many devices attempt to access a base station (BS) simultaneously in a short period of time. We discuss the challenge of the gap between the theoretical maximum throughput and the actual throughput. A gap occurs when the BS cannot change the number of preambles for a random access channel (RACH) until multiple numbers of RACHs are completed. In addition, a preamble partition approach is proposed in this paper that uses two groups of preambles to reduce this gap. A performance evaluation shows that the proposed approach increases the average throughput. For 100,000 devices in a cell, the throughput is increased by 29.7% to 114.4% and 23.0% to 91.3% with uniform and Beta-distributed arrivals of devices, respectively.

• Asian Journal for Public Opinion Research
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• 제7권3호
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• pp.143-168
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• 2019

With much attention being paid to the rapid growth of wrist-worn smart devices, this study aimed to examine the micro-processes that determine an individual's adoption of smart bands and smartwatches. Primarily relying on the theoretical background of the extended technology acceptance model (TAM II), this study explored relationships between three groups of predictors-social, personal, and device-oriented-and the three main components of the original TAM: perceived usefulness (PU), perceived ease of use (PEOU), and behavioral intention (BI). Results from the path analysis indicated multiple factors played significant roles in increasing the PU, PEOU, and BI of wristworn smart devices: subjective norms, social image, self-efficacy, perceived service diversity, and perceived reasonable cost. The main findings from this research contribute to significantly improving the understanding of the main factors leading people to adopt wrist-worn smart devices.

• International Journal of Knowledge Content Development & Technology
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• 제12권1호
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• pp.7-16
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• 2022

With the proliferation of activity-tracking devices and other smart tools, more users leverage these personal informatics technologies to track their physical and fitness-related activities. The research on the benefits (and limitations) of these devices tends to focus on the use of a single tool, leaving out the interactions among multiple technologies, and how these interactions influence the way users perceive their affordances. Building from an ecological perspective, I extend this research by providing insight into the competitive and complementary relationships among activity tracking devices and other fitness-related and personal informatics technologies within the device ecology of technologies around the user. The affordances of these devices are therefore not enacted in isolation but are relational to understanding of other technological options and differing personal preferences and goals of the user.

• Educational Technology International
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• 제24권2호
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• pp.331-358
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• 2023

This paper explores the impact of mobile device usage frequency in the classroom on students' perceptions of their use. To assess this, we created a survey that measured students' perceived frequency, usefulness, and convenience of using mobile devices, using a reversed Technology Acceptance Model. Through the analysis of responses from 781 Korean students, utilizing confirmatory item factor analyses and a structural equation mixture model, we found that the effect of frequent mobile device use on students' positive perceptions is non-linear. As the frequency reaches to a certain level, the effect sizes of the frequency in the positive perceptions diminishes. Additionally, students who used mobile devices less frequently in class reported higher levels of difficulties in using the devices. This study introduces a tool for evaluating multiple aspects of students' perceptions regarding mobile device use and offers a framework for understanding the relationship between usage frequency, usefulness, and convenience.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 추계학술발표대회
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• pp.4.1-4.1
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• 2009

The dream of futurists andtechnologists is to build complex, multifunctional machines so small that theycan only be seen with the aid of a microscope. The unprecedented technologyadvancements in miniaturizing integrated circuits on semiconductors, and theresulting plethora of sophisticated, low cost electronic devices demonstratethe impact that micro/nano scale engineering can have when applied only to thearea of electrical and computer engineering. Emerging research efforts indeveloping organic and inorganic nano materials together with using micro/nanofabrication techniques for implementing integrated multifunctional devices hopeto yield similar revolutions in other engineering fields. By cross linking theindividual engineering fields through micro/nano technology, various organicand inorganic materials and miniaturized system devices can be developed thatwill have future impacts in the IT and life science applications. Yet to buildthe complex micromachines and nanomachine of the future, engineering will needto develop the technology capable of seamlessly integrating these materials andsubsystems together at the micro and nano scales. The micromachines of thefuture will be “integrated nanosystems,” complex devices requiring the integration of multiple materials,phenomena, technologies, and functions at the same platform. To develop thistechnology will require great efforts in materials science and engineering, infundamental and applied sciences. In this talk, we will first discuss thenature of micro and nanotechnology research for IT and life sciences, and thenintroduce selected current activities in micro and nanotechnology research fororganic and inorganic materials and devices. The newly developed micro/nanofabrication processes and devices, combined with in-depth scientificunderstandings of materials, can lead to rapid development of next generationsystems for applications in IT and life sciences.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.332-338
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• 2008

This paper handles, implementation of multiple access bidirectional serial communications protocol using two common DC power lines, whict are power supply and ground, connecting multiple devices. Communication between the host and the multiple clients are performed using unique packet data with device ID unique to each devices connected on the common power lines. Host initiates data communications by transmitting command packet to the designated client with the client's ID and the client responds by transmitting response packet to the host and in this way, multiple clients and host exchange the packet through the common power lines. The normal voltage of the power communication line maintains 24V corresponding to level 1 and the host drops the voltage to 12V on sending level 0 signal, also the clients normally keeps the line voltage to 24V use pull-down circuit to drop the voltage to 12V on sending level 1 signal. Power supply originates from the host, the host senses the voltage level of the power communication lines and when the clients activates pull down circuit to send level 0 signal and the voltage drops to 12V, the hosts switches power source from 24V to 12V. Also, when clients deactivate pull down circuit to send level 1 signal, the host senses the voltage increase and switches the power source from 12V to 24V. Experimental circuit is designed with one hosts and four clients and verified the power line voltage switching operation depending on the data signal levels on the power line. The proposed research result can be applied to two wire power communications system with one host and multiple low current consumption clients.