• 전자공학회논문지 IE
• /
• v.46 no.1
• /
• pp.31-36
• /
• 2009

This study was to simulate it that the sending receiving vehicles run on the general national roads with the one-way two-lanes at 80[km/h] speed. This study was to select 280[m] radius of curvature based on the statistical data with high rate of traffic accidents, 140[m] length of direct roads considering the stopping stadia, 90[m] length of curve, and 8 points of curved roads at 11.25[m] intervals. As a result above, when the distance between the sending and receiving vehicles became more than 111[m], the propagation path of reflected wave by the adjacent vehicles became longer than the propagation path of reflected wave by the left/right reflectors because the number of repeated reflection increased. In this study, the repeated reflection for the propagation's reach to the receiving vehicles was about $1{\sim}2$[times] as it supposed it less than 111[m]. Accordingly, it found out that the propagation path of reflected wave received through the left/right reflectors was about $1{\sim}1.5[m]$ larger than the reflected wave produced by the adjacent vehicles regardless of lanes on which the sending and receiving vehicles were located.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.40 no.7
• /
• pp.507-517
• /
• 2003

A single fiber failure in mesh-based WDM networks may result in the loss of a large number of data. To remedy this problem, an efficient restoration algorithm for a single fiber failure in the mesh- based WDM network is necessary. We propose a new algorithm for restoration scheme in WDM networks and compare it with previous schemes. Path restoration and link restoration are two representative restoration schemes which deal with only a single link failure. In this paper, we propose two kinds of efficient restoration scheme. In the proposed schemes the restoration path for each link failure is not secured. The mesh network is decomposed into a number of small loops. In one algorithm, any link failure in a certain loop is regarded as the failure of the loop and the restoration lightpath is selected by detouring the failed loop. In another scheme any link failure in a certain loop is restored within the loop. We compare performance of the proposed schemes with conventional path restoration scheme and link restoration scheme. Simulation results show that CPU time in the proposed schemes decreases compared with that in path restoration scheme and link restoration scheme, although total wavelength mileage usage increases by 10% to 50%.

• The KIPS Transactions:PartC
• /
• v.18C no.3
• /
• pp.179-186
• /
• 2011

Wireless Mesh Network technology refers to the technology which establishes wireless network whose transmission speed is similar to that of the wire system, and provides more enhanced flexibility in the building of network, compared to the existing wired network. In addition, it has the feature of less mobility and less restriction from the energy effect. However, there follow many considerations such as system overhead in the case of setting or the selection of multi-path. Accordingly, the focus is on the design and optimization of network which can reflect this network feature and the technology to establish path. This paper suggests the methods on the programming of path in Wireless Mesh Network routing by applying the evaluation value of node service, making use of the loss rate of data, the hop count of bandwidth and link and the traffic status of node, considering the performance of link and load in the fitness evaluation function, in order to respond to the programming of multi-path effectively.

• The Journal of the Korea Contents Association
• /
• v.9 no.9
• /
• pp.1-8
• /
• 2009

H.264/AVC video coding standard uses the rate distortion optimization method which determines the best coding mode for macroblock(MB) to improve coding efficiency. Whereas RDO selects the best coding mode, it causes the heavy computational burden comparing with previous standards. To reduce the complexity, in this paper, a fast intra prediction mode decision algorithm using directional gradients is proposed. The proposed algorithm is composed of 2-path structure. In the first path, $16{\times}16$ intra prediction mode is determined using directional gradients. In the second path, 3 modes instead of 9 modes are chosen for RDO to decide the best mode for $4{\times}4$ block. Finally, the two modes determined in the two-path decision process are compared to decide the final block mode. Experimental results show that the computation time of the proposed method is decreased to about 77% of the exhaustive mode decision method with negligible quality loss.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.5
• /
• pp.985-990
• /
• 2007

The method of enhancing visibility in optical fiber sensor was investigated by improving coherence length of light source. The optical feedback technique is used to enhance coherence length in fiber laser which generates laser in near infrared wavelength region and utilizes low loss characteristics of optical communication grade fiber. In this paper, the effect to coherence length by short and long optical feedback paths are investigated by using Mach-Zehnder interferometer technique. The effect to coherence length by changing optical feedback power and optical modulation are investigated. The spectral drift was calculated by measuring the degree of phase perturbation in unbalanced Mach-Zehnder interferometer having loom path difference. The short optical feedback path was effective to reduce spectral drift to 450kHz/sec and the long optical feedback path in combination with short optical feedback path was found to further reduce spectral drift to 50kHz/sec.

• The Journal of the Acoustical Society of Korea
• /
• v.42 no.4
• /
• pp.357-363
• /
• 2023

In underwater signal processing, separating individual signals from mixed signals has long been a challenge due to low signal quality. The common method using Short-time Fourier transform for spectrogram analysis has faced criticism for its complex parameter optimization and loss of phase data. We propose a Triple-path Recurrent Neural Network, based on the Dual-path Recurrent Neural Network's success in long time series signal processing, to handle three-dimensional tensors from multi-channel sensor input signals. By dividing input signals into short chunks and creating a 3D tensor, the method accounts for relationships within and between chunks and channels, enabling local and global feature learning. The proposed technique demonstrates improved Root Mean Square Error and Scale Invariant Signal to Noise Ratio compared to the existing method.

• Journal of Korean Clinical Nursing Research
• /
• v.29 no.3
• /
• pp.249-260
• /
• 2023

Purpose: The study aimed to examine the effects of nurse staffing levels on patient outcomes in long-term care hospitals in South Korea using path analysis. Methods: We conducted a secondary analysis of national data, which included the 2021 hospital assessment results of long-term care hospitals from the Health Insurance Review and Assessment Service. Data collection was performed between June 19 and June 27, 2023. The study sample consisted of 1,215 hospitals, and we analyzed the data using SAS 9.4 and Mplus 8 software. Results: The average numbers of patients per registered nurse, certified nursing assistant, and nursing staff, including both registered nurses and certified nursing assistant, was 10.00, 7.43, and 4.00, respectively. Path analysis revealed that the number of patients per registered nurse had direct effects on improvements in activities of daily living and indirect effects on indwelling catheterization, pressure ulcer improvement, and weight loss. The number of patients per certified nursing assistant had direct effects on new pressure ulcer development and pressure ulcer improvement, with no indirect effects. The number of patients per nursing staff had direct effects on pressure ulcer improvement and no indirect effects on other patient outcomes. Conclusion: The findings suggest that establishing policies to evaluate staffing levels of registered nurse and certified nursing assistants separately is necessary in order to improve registered nurse staffing levels and patient outcomes in long-term care hospitals.

• Archives of design research
• /
• v.20 no.1 s.69
• /
• pp.65-78
• /
• 2007

The mobile phone and wireless network, location based technology and other newly introduced technologies and communication media gave birth to the new terminology "ubiquitous" and are changing our daily life. Influence of such technologies and communication media is not an exception in the arts. New media art pieces using these technologies are increasing, and taking on the characteristics of public art within a wider scope of a city as a backdrop, beyond the traditional boundaries of art galleries. Of such art, locative media art using locative media has a closer relationship with city space than any other form of an, and makes various attempts to allow the spectator to reinterpret and experience city space and induce communication. These characteristics of locative media art can be considered as a method that can solve quality problems of the city space, especially the loss of the sense of place and the absence of communication. is one such locative media project with a purpose of solving quality problems of city space, especially the recovery of commercial sites and inducing communication. This project uses the paths of the city as its canvas, movement of people as its brush, the color of the roads as its pallet, and by allowing the partakers to draw paths of their own and to share their paths with others. People are encouraged to share stories about their paths. The project proceeds using barcodes that are frequently used commercially. When users wish to create their own place, they can enter their place and colors of their choice using input devices installed in the city space. Paths that are created through such a process will be displayed in public areas throughout the city, shared with others, and can create and share a stories about the city using on/off-line media.

• Progress in Superconductivity and Cryogenics
• /
• v.5 no.1
• /
• pp.76-80
• /
• 2003

A contractible heat pipe is designed and tested to improve cooling performance of conduction cooled superconducting magnet. When the heat pipe temperature drops below the triple point temperature, heat pipe working fluid freezes to create low pressure. From this moment the heat pipe does net work any more (OFF state) and it just works as a heat leak path when the temperature of the first stage is higher than that of the second stage. Considering small cooling capacity of the second stage around 4.2 K, the conduction loss is not negligible. Therefore, the contractible heat pipe, made of a metal bellows and copper tubes, was considered to eliminate the conduction loss. Nitrogen and argon are as working fluid of heat pipe. The copper block is cooled down with these heat pipe and the cooling performance for each heat pipe is compared. At off state, the bellows is contracted due to the low pressure of heat pipe and the evaporator section of the heat pipe is detached about 3 mm from the second stage cold head of the cryocooler. In this way, we tan eliminate the conduction loss through the heat pipe wall.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2014.04a
• /
• pp.581-587
• /
• 2014

Intake silencers of high performance and with less pressure drop are developed for a household oxygen generator. First, the acoustic power of the target oxygen generator are experimentally evaluated according to ISO code. Then, the transmission loss of and the flow characteristics inside the existing intake silencer are predicted and analyzed. On a basis of these results, two intake silencers are proposed, which are designed to induce the swirling flow inside the intake silencer and thus to reduce the flow loss. The predicted TL and the pressure drop for these two new silencers are compared to the existing one, which shows that the proposed ones have higher TLs as well as less pressure drop. The reason for these improvements are explained by investigating the flow characteristics of the new silencers in detail.