• Journal of Digital Contents Society
• /
• v.15 no.1
• /
• pp.129-136
• /
• 2014

Wi-Fi fingerprinting system is a very popular positioning method used in indoor spaces. The system depends on Wi-Fi Received Signal Strength (RSS) from Access Points (APs). However, the Wi-Fi RSS is changeable by multipath fading effect and interference due to walls, obstacles and people. Therefore, the Wi-Fi fingerprinting system produces low position accuracy. Also, Wi-Fi signals pass through walls. For this reason, the existing system cannot distinguish users' floor. To solve these problems, this paper proposes a LED fingerprinting system for accurate indoor positioning. The proposed system uses a received optical power from LEDs and LED-Identification (LED-ID) instead of the Wi-Fi RSS. In training phase, we record LED fingerprints in database at each place. In serving phase, we adopt a K-Nearest Neighbor (K-NN) algorithm for comparing existing data and new received data of users. We show that our technique performs in terms of CDF by computer simulation results. From simulation results, the proposed system shows that a positioning accuracy is improved by 8.6 % on average.

• Journal of Korea Society of Industrial Information Systems
• /
• v.25 no.2
• /
• pp.39-47
• /
• 2020

This paper introduces a novel system-level framework that derives energy efficient electric vehicle (EV) driving speed profile to extend EV driving range without additional cost. This paper first implements an EV power train model considering forces acting on a driving vehicle and motor efficiency. Then, it derivate the minimum-energy driving speed profile for a given driving mission defined by the route. This framework first formulates an optimization problem and uses the dynamic programming algorithm with a weighting factor to derive a speed profile minimizing both of energy consumption and driving time. This paper introduces various weighting factor tracking methods to satisfy the driving time constraint. Simulation results show that runtime of the proposed scaling algorithm is 34% and 50% smaller than those of the binary search algorithm and greedy algorithm, respectively.

• Journal of Korea Society of Industrial Information Systems
• /
• v.24 no.5
• /
• pp.77-93
• /
• 2019

The purpose of this study is to investigate the effect of organizational brand internalization on organizational brand permanence. Specifically, organizational brand internalization influences customer orientation, brand attachment, and organizational brand permanence. Also, we examined the effect of brand attachment on the relationship between customer orientation and organizational brand permanence. As a result of empirical research, organizational brand internalization plays an important role in enhancing employee's attachment to brand and positively forming relationship with customers. In other words, as brand attachment increases, employees in the organization know and share customer's needs and provide core competencies for the organization's long-term development. Therefore, companies need to strengthen their internal brand power by organizing their brands into a single concept, and to realize organizational integration of employees based on them. Finally, this study suggested practical implications and future research directions from this perspective.

• Korean journal of communication and information
• /
• v.32
• /
• pp.295-332
• /
• 2006

This study inquires at behavior and attitude of gatekeepers at major Korean media in the process of selecting and covering newsmakers, with focusing on factors, paths and practices in making news on the people. The study assumes that gatekeepers' social networking process with social elites, based on birth places, alma mater and kinship, plays great role in making people in the news. The study applies methods of in-depth interviews with people-page gatekeepers and content analysis of news on newsmakers. The in-depth interviews and content analysis unveil that people-page gatekeepers tend to support high society and social elite group. Furthermore, through the process of news-making, the gatekeeper group shares social capital such as economic exchanges and socio-political influences with social elite group. The result of interviews and analysis confirm that social networking based on personal affiliation plays as an important factor in selecting and covering newsmakers. With in-depth analysis of news contents, the study finds out that social elite groups of top government officials, corporate CEOs, medical doctors, lawyers, judges, prosecutors, college professors, cultural celebrities and journalists, who are predominantly male, appear on people pages much frequently out of proportion. The content analysis also reveal that 'personal news,' which cover personal and private life or unilaterally promote newsmakers predominate in terms of frequency and amount over socially-important or pubic-interested 'public news.' In terms of news values, fragmentary news composed of sensational, personal and gossiping elements appear more frequently than socially-meaningful news with strong social issues and public messages.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.14 no.8
• /
• pp.845-854
• /
• 2003

In this paper, the characteristics of compensation for WDM channel signal distortion due to both chromatic dispersion and Ken effect in 1,000 km 200 Gbps(5${\times}$40 Gbps) WDM systems was investigated. The WDM system has a path-averaged intensity approximation(PAIA) mid-span spectral inversion(MSSI) as a compensation method. This system has a highly nonlinear dispersion shifted fiber(HNL-DSF) optical phase conjugator(OPC) in the mid-way of transmission line. In order to evaluate the degree of compensation, 1 dB eye opening penalty(EOP), bit error rate(BER) characteristics and power penalty of 10$\^$-9/ BER are used. It is confirmed that HNL-DSF is an useful nonlinear medium in OPC fur wideband WDM system with PAIA MSSI and that the optimal compensation for WDM channel distortion is achieved by the selection of pump light power of OPC, which equalize the conjugated light power into the second half fiber section with the input WDM signal light power depending on total transmission length, dispersion coefficient of fiber, OPC pump light wavelength, conversion efficiency of WDM channel in OPC.

• Korean Journal of Optics and Photonics
• /
• v.16 no.6
• /
• pp.535-541
• /
• 2005

We report on the development of a passively mode-locked near-infrared femtosecond laser with Cr:YAG crystal that operates near room temperature. The laser wavelength could easily be tuned by using only the internal prism pair over 110 nm from 1400 nm to 1510 nm in cw and over about 30 nm in mode-locked operation, respectively Maximum cw output powers of 810 mW were obtained with $1.5 \%$ output coupler for absorbed pump powers of 7.6 W. For compensation of the internal group velocity dispersion, an IR graded prism pair was used. The Cr:YAG laser delivered nearly Fourier-transform limited pulses with a pulse duration as short as 64 fs at 100 MHz repetition rate. In the mode-locked regime, the laser was operating at 1510 nm with a spectral bandwidth of 44 nm. In order to avoid unstable mode-locking and power instabilities, self-built tubes were inserted into the beam path in the resonator and purged with N2 gas. Finally, output powers of the Cr:YAG laser were optimized to 250 mW fer long time stable mode-locked operation.