• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.18 no.9
• /
• pp.2079-2086
• /
• 2014

Shipbuilding production management is one of the most significant activities in productivity improvement. Shop-floor managers and production planners still do not have enough production information for shop-floor scheduling due to shortage of information sharing among them. In this research, main issues were derived from requirement analysis between production planning and shop-floor control to establish a software system architecture for ship production monitoring system(SPMS), which is developed with component based design(CBD). The proposed system's key functions cover from block shop assembly to quay outfitting stage to visualize production progress as well as to maximize production information sharing. The system will allow more reliable and accurate production information to permeate down to members of the workforce just in time.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.21 no.8
• /
• pp.1508-1516
• /
• 2017

Multipath TCP (MPTCP) is a transport layer protocol that supports multipath transmission. If a bufferbloat occurs in one of the subflows of MPTCP, HoL blocking occurs at the receiver due to the difference in packet arrival time among paths. In MPTCP, HoL blocking degrades not only the performance of the path where bufferbloat occurs, but also the performance of other paths. In this paper, we propose a bandwidth measurement based scheduler to solve this problem. Bandwidth measurement based scheduler is designed to measure the bandwidth of each subflow and to perform packet scheduling based on it. In order to verify the proposed scheduler, we implemented the proposed scheduler in the Linux kernel and constructed a testbed in which bufferbloat occurs. Experimental results show that the proposed scheduler has better performance than the legacy MPTCP in bufferbloat environment.

• The KIPS Transactions:PartA
• /
• v.9A no.4
• /
• pp.603-614
• /
• 2002

Delivery efficiency of e-learning media can be influenced by authoring processes. Generally, a moving picture recorded by video camera can be delivered to student by multimedia streaming service, using media server technology. A e-learning media authored by lecture authoring tool is played in a student application by download-based delivery system. Recently, some animation know-how are applied to author e-learning media by hand-operation. In this paper, we suggest a client-based streaming service for the e-leaning media consists of media files and integration data The lecture of e-learning media nay be divided into some time-based small blocks. Each blocks can be located distributed site. The student system gather those blocks by download-scheduling. This is a valid method for QoS guarantee streaming services. In addition to our study, lecturers can author composite e-learning media includes media files and dynamic web pages simply, The distributed e-learning media files of our study is managed by multi-author and updated rapidly.

• Journal of the Korea Society of Computer and Information
• /
• v.24 no.10
• /
• pp.57-64
• /
• 2019

In this paper, we study a polynomially solvable case of the inverse interval graph coloring problem. Given an interval graph associated with a specific interval system, the inverse interval graph coloring problem is defined with the assumption that there is no proper K-coloring for the given interval graph, where K is a fixed integer. The problem is to modify the system of intervals associated with the given interval graph by shifting some of the intervals in such a way that the resulting interval graph becomes K-colorable and the total modification is minimum with respect to a certain norm. In this paper, we focus on the case K = 1 where all intervals associated with the interval graph have length 1 or 2, and interval displacement is only allowed to the righthand side with respect to its original position. To solve this problem in polynomial time, we propose a two-phase algorithm which consists of the sorting and First Fit procedure.

• The Journal of Korean Obstetrics and Gynecology
• /
• v.33 no.1
• /
• pp.116-127
• /
• 2020

Objectives: The purpose of this study is to analyze csatisfaction with clinica1 training in the department of Korean Medicine Obstetrics and Gynecology and the related factors. Methods: All the students on the graduating class of school of Korean Medicine, Dong-Shin University must be trained for 1 year in the department of Korean Medicine Obstetrics and Gynecology according to clinical training guideline including Objective Structured Clinical Examination (OSCE). After completing clinical training, we distributed questionaries to them about a reflex of the object of study, usefulness, difficulty, satisfaction and preference. And then, we analyzed the related factors including descriptive statistics, frequency analysis and correlation analysis by SPSS 12.0. Results: In general, a reflex of the aim of study (7.31±1.59), satisfaction with contents (7.44±1.58), and difficulty (6.13±1.34) were evaluated restectively. There is no statistically significant difference with sex. There is a statistically significant positive correlation between a reflex of the aim of study and satisfaction with contents. The primary preferences of clinical practice were Clinic Training, Ward Training, PBL (Problem Based Learning), OSCE. In OSCE, a reflex of the aim of study (7.04±1.83) and usefulness (7.02±1.97) were highly evaluated. There is no statistically significant difference with sex. The primary preferences for clinical OSCE practice were breast examination, genital examination, ultrasound scan, and pap smear. Facilities and equipment (6.84±2.01), contents of clinical training (7.29±1.83), the handout (7.20±1.98) and time scheduling (7.29±1.90) were evaluated respectively in general composition of clinical training. Conclusions: Clinical training program in the department of Korean Medicine Obstetrics and Gynecology can be highly estimated from the viewpoint of satisfaction with clinical training and the related factors.

• Nuclear Engineering and Technology
• /
• v.40 no.1
• /
• pp.49-68
• /
• 2008

The purpose of this paper is to extensively review the condition monitoring (CM) techniques using empirical models in an effort to reduce or eliminate unexpected downtimes in general industry, and to illustrate the feasibility of applying them to the nuclear industry. CM provides on-time warnings of system states to enable the optimal scheduling of maintenance and, ultimately, plant uptime is maximized. Currently, most maintenance processes tend to be either reactive, or part of scheduled, or preventive maintenance. Such maintenance is being increasingly reported as a poor practice for two reasons: first, the component does not necessarily require maintenance, thus the maintenance cost is wasted, and secondly, failure catalysts are introduced into properly working components, which is worse. This paper first summarizes the technical aspects of CM including state estimation and state monitoring. The mathematical background of CM is mature enough even for commercial use in the nuclear industry. Considering the current computational capabilities of CM, its application is not limited by technical difficulties, but by a lack of desire on the part of industry to implement it. For practical applications in the nuclear industry, it may be more important to clarify and quantify the negative impact of unexpected outcomes or failures in CM than it is to investigate its advantages. In other words, while issues regarding accuracy have been targeted to date, the concerns regarding robustness should now be concentrated on. Standardizing the anticipated failures and the possibly harsh operating conditions, and then evaluating the impact of the proposed CM under those conditions may be necessary. In order to make the CM techniques practical for the nuclear industry in the future, it is recommended that a prototype CM system be applied to a secondary system in which most of the components are non-safety grade. Recently, many activities to enhance the safety and efficiency of the secondary system have been encouraged. With the application of CM to nuclear power plants, it is expected to increase profit while addressing safety and economic issues.

• Korean Journal of Optics and Photonics
• /
• v.14 no.6
• /
• pp.663-668
• /
• 2003

We studied a localized hologram recording method that can be used in a disk-shaped medium. In this method, the reference beam is focused by use of a cylindrical lens to get a thin spot in the medium, and then a hologram is recorded in that spot by illuminating the signal beam. Many localized holograms are multiplexed by shifting the medium by a distance more than the thin spot size of the reference beam. This method does not need recording-time scheduling for uniform diffraction efficiencies. We show that a minimal required thickness of the recording medium exists for a given spot size of the signal beam. We performed experiments for data storage and retrieval, and obtained a storage density of 20 bits/${\mu}{\textrm}{m}$$^2$ and a raw-bit error rate (RBER) of 2.5${\times}$10$^{-3}$ , when a 2 mm-thick Fe-doped LiNbO$_3$ crystal was used.

• Korean Journal of Soil Science and Fertilizer
• /
• v.48 no.5
• /
• pp.499-504
• /
• 2015

Decision making by farmers regarding irrigation is critical for crop production. Therefore, the precision irrigation technique is very important to improve crop quality and yield. Recently, much attention has been given to remote sensing of crop canopy temperature as a crop water-stress indicator, because it is a scientifically based and easily applicable method even at field scales. This study monitored a series of time-variant canopy temperature of cucumber under three different irrigation treatments: under-irrigation (control), optimal-irrigation, and over-irrigation. The difference between canopy temperature ($T_c$) and air temperature ($T_a$), $T_c-T_a$, was calculated as an indicator of cucumber water stress. Vapor pressure deficit (VPD) was evaluated to define water stress on the basis of the temperature difference between leaf and air. The values of $T_c-T_a$ was negatively related to VPD; further, cucumber growth in the under- and over-irrigated fields showed water stress, in contrast to that grown in the optimally irrigated field. Thus, thermal infrared measurements could be useful for evaluating crop water status and play an important role in irrigation scheduling of agricultural crops.

• The Journal of the Korea Contents Association
• /
• v.20 no.12
• /
• pp.230-240
• /
• 2020

To develop a virtual world-based immersive tutoring system, we would like to develop a simulation in the spatial aspect to maximize the diversity and realism of the situation. This implementation requires the modeling of virtual space as well as the knowledge and intelligent thinking functions of virtual humans. First, information structures are needed to simulate the hierarchical and multifaceted composition of space and the corresponding knowledge of virtual humans. Specifically, four structures for 2.5D spatial distribution expression, complex spatial relationship expression, object expression, and temporal and spatial representation of events are developed respectively. It then uses these expressed knowledge to develop the spatial thinking function of virtual humans needed to make spatial movement. In general, events have a chain effect on adjacent or connected objects through force, resulting in a variety of situations and reflected in the planning of the next action by the virtual humans involved. For this purpose, the development of events according to historical trends is recorded on the representation structure of time and space. It embodies typical events to demonstrate the feasibility of independent behavior in complex spaces among virtual people.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.23 no.12
• /
• pp.1638-1643
• /
• 2019

In this paper, we propose an adaptive-perturbation-aided opportunistic precoding (APOP) scheme for multiple-input multiple-output (MIMO) systems. To update a precoding matrix in MIMO systems, the proposed algorithm produces a random perturbation in each time slot. Then the additional adaptive perturbation is also applied, which depends on the reports of achievable data-rates from users. If the prior random perturbation increased the data rate, the adaptive perturbation is set to be the same as the prior random perturbation, otherwise the negative value of the prior random perturbation is applied for adaptive perturbation. Furthermore, to enhance the achievable data rates, the information on the stored precoding matrices in the memory as well as the currently generated precoding matrix is used for scheduling. Simulation results show that compared to conventional opportunistic precoding schemes, higher data rates are achieved by the proposed APOP scheme, especially when there are a relatively small number of users.