• International journal of advanced smart convergence
• /
• v.8 no.2
• /
• pp.109-115
• /
• 2019

Currently, LPWA(Low Power Wide Area) communication technology is widely used due to the development of IoT(Internet of Things) technology. Among the LPWA technologies, LoRaWAN(Long Range Wide Area Network) is widely used in many fields due to its wide coverage, stable communication speed, and low-cost modem module prices. In particular, LoRa(Long Range) can easily construct LoRaWAN with a dedicated gateway. So many organizations are building their own LoRaWAN-based networks. The LoRaWAN Gateway receives the LoRa packet transmitted from an End-device installed in the adjacent location, converts it into the Internet protocol, and sends the packet to the final destination server. Current LoRa Gateway uses a single-hop method, and each gateway must include a communication network capable of the Internet. If it is the mobile communication(i.e., WCDMA, LTE, etc.) network, it is required to pay the internet usage fee which is installed in each gateway. If the LoRa communication is frequent, the user has to spend a lot of money. We propose an idea on how to design a multi-hop protocol which enables packet routing between gateways by analyzing the LoRaWAN communication method implemented in its existing single-hop way in this paper. For this purpose, this paper provides an analysis of the standard specification of LoRaWAN and explains what was considered when such protocol was designed. In this paper, two gateways have been placed based on the functional role so as to make the multi-hop protocol realized: (i) hopping gateway which receives packets from the end-device and forwards them to another gateway; and (ii) main gateway which finally transmits packets forwarded from the hopping gateway to the server via internet. Moreover, taking into account that LoRaWAN is wireless mobile communication, a level-based routing method is also included. If the protocol proposed by this paper is applied to the LoRaWAN network, the monthly internet fee incurred for the gateway will be reduced and the reliability of data transmission will be increased.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.13 no.1
• /
• pp.27-38
• /
• 2003

Most password-authenticated key exchange schemes in the literature provide an authenticated key exchange between a client and a server based on a pre-shared password. With a rapid change in modem communication environments, it is necessary to construct a secure end-to-end channel between clients, which is a quite different paradigm from the existing ones. In this paper we propose a new framework which provides a password-authenticated ky exchange between clients based only on their two different Passwords without my Pre-shared secret, so called Client-to-Client Password-Authenticated Key Exchange(C2C-PAKE). Security notions and types of possible attacks are newly defined according to the new framework We prove our scheme is secure against all types of attacks considered in the paper. Two secure C2C-PAKE schemes are suggested, one in a cross-realm setting and the other in a single-sorrel setting.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.14 no.4
• /
• pp.97-110
• /
• 2004

As modem web services become enormously complex, web attacks has become frequent and serious. Existing security solutions such as firewalls or signature-based intrusion detection systems are generally inadequate in securing web services, and analysis of raw web log data is simply impractical for most organizations. Visual display of "interpreted" web logs, with emphasis on anomalous web requests, is essential for an organization to efficiently track web usage patterns and detect possible web attacks. In this paper, we discuss various issues related to effective real-time visualization of web usage patterns and anomalies. We implemented a software tool named SAD (session anomaly detection) Viewer to satisfy such need and conducted an empirical study in which anomalous web traffics such as Misuse attacks, DoS attacks, Code-Red worms and Whisker scans were injected. Our study confirms that SAD Viewer is useful in assisting web security engineers to monitor web usage patterns in general and anomalous web sessions in particular.articular.

• The Journal of the Korea Contents Association
• /
• v.6 no.12
• /
• pp.287-295
• /
• 2006

New Recently introduced to domestic market, MMA(Mixed Martial Arts) is growing very rapidly, thereby acquiring the property of sub-culture. With its proper function of providing dynamism and vitality, it also becomes the target of apprehension for its social dysfunction due to excessive violence. However, it is important to recognize MMA as a phenomenon and to understand the cultural flow inside MMA. It is required that the space where MMA is held should provide new experience in each contest. It is necessary to prepare very diverse productions for this purpose. While comprehension on this cultural and spatial phenomenon could mean one of starting point of space creation of space designer, it is necessary to study in the contextual aspect including historic and psychological approach. Thus, this study aims to understand one of the diverse meanings of modem space by investigating the space inherent in the phenomenon of MMA.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.11 no.2
• /
• pp.134-144
• /
• 2007

In this study, a smart sensor unit is developed by using the smart sensor technology that is being rapidly developed in recent years for structural health monitoring system, and its performance is evaluated through various experiments, and also, damage detection experiment is performed on a model structure. This paper as the first half of this study contains the development and performance evaluation of the smart sensor. In the latter half of this study, structure damage detection experiment is performed for the application of verified smart sensor unit into structural health monitoring, and it is compared with a wire measurement system. The smart sensor is developed by using high-power wireless modem, MEMS Sensor and AVR microcontroller, and an embedded program is also developed for the control and operation of the sensor unit. To verify the performance of the smart sensor, many experiments are performed for sensitivity and resolution analysis tests, data acquisition by using cantilever beam and shaker, and on-site application using actual bridge. As a result, the smart sensor proves to be satisfactory in its performance.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.12 no.4
• /
• pp.149-160
• /
• 2008

In this study, the research was carried out on how to identify the modal parameter by acquiring the output response of the structure only through the smart sensor system. The objective of this research is to verify the performance and the on-site adaptability of the smart sensor system that have been actively researched as the advanced measuring system so far. Smart Sensor System was developed so that the real-time dynamic measurement can be performed by means of MEMS-type accelerated sensor, 8 bit CPU, wireless MODEM. In the modal parameter identification test, random excitation was added to the cantilever beam, and then the response of the structure was obtained using the smart sensor system and the wire measurement system respectively. In analyzing the data, modal parameter was identified using NExT & ERA algorithm. Furthermore, the optimal measurement location was selected through EOT algorithm in order to obtain the qualified output response. Result of the test, it was possible to verify the on-site applicability of the smart sensor.

• Journal of Positioning, Navigation, and Timing
• /
• v.13 no.3
• /
• pp.355-363
• /
• 2024

Time synchronization is crucial for ensuring the reliable operation of modern economic and social infrastructures. Techniques such as Global Navigation Satellite System (GNSS)-based methods and Two-Way Satellite Time and Frequency Transfer (TWSTFT) play key roles in precise time comparison and synchronization. TWSTFT, in particular, is recognized for its ability to achieve sub-nanosecond accuracy in time transfer, making it indispensable in fields such as satellite navigation. This paper proposes a comprehensive performance evaluation method for TWSTFT modems, emphasizing pre-validation in controlled environments to mitigate operational challenges. Using the proposed evaluation method, the study presents the standard deviation of RTT according to C/N₀ and compares it with the datasheet of a commercial TWSTFT modem. Through this approach, the aim of this study is to enhance the reliability and accuracy of TWSTFT-based time synchronization across diverse applications.

• Journal of Science of Art and Design
• /
• v.11
• /
• pp.5-35
• /
• 2007

When it comes to art, the two conflicting themes of 'scientific progress' and the 'nature' have often motivated the advent of the new mode of arts. By the late 20th century, uniform and simplified mode of arts, inspired by scientific and technological progress of that time, was gradually disillusioned by the contemporaries due to the adverse effect of science on human life. In this context, naturalism pursuing for harmony of human and the nature came up as an alternative to those living in the 21st century. The pendulum has swung from minimalism to naturalism. Though the quantitative improvement of human life cannot be denied, the uprise of such problems as environmental pollution and exhaustion of natural resources degraded the quality of human life, which, eventually, shifted the attention to the theme - 'revival of naturality.' Therefore, this thesis intends to represent the modem interpretation of the 'revival of naturality' by applying the major expressions of Art Nouveau that also emphasized naturalism. Art Nouveau found its motifs from organic figures of natural beings and put them to designs of decorative arts. This carries a historical significance in that Art Nouveau boldly revolutionized historicism, which only repeated adoption and modification of the existing modes of arts, and opened it to the modem design with new attempts to practical applications of the arts. Art Nouveau, which means 'new art', prospered from the late 19th century to the early 20th century, and even after one century, it is highly appreciated, reviving as novel and vivid forms in this contemporary art. Art Nouveau based on naturalism has revisited our contemporary period when naturalism and feminized romanticism came into fashion and its common motifs revive in different jenre of arts such as fashion, furniture, glass works, and jewelry works. This study illustrates and analyzes the works of four major artists who gave a specific attention to botanical motifs of Art Nouveau and applies decorative beauty of highly sophisticated and organic curved lines and the expressional forms of botanical figures to design. Art Nouveau proved this; the nature herself is as beautiful as she can be. Within Art Nouveau, the true humanism can be revitalized with the 'revival of naturality'. This study rediscovered the boundless potential of modern interpretation and application of Art Nouveau in decorative art and design.

• Journal of the East Asian Society of Dietary Life
• /
• v.13 no.5
• /
• pp.343-352
• /
• 2003

This study was conducted to investigate the actual state of use and necessity of Korean traditional Pyebaeck foods using questionnaire. The subjects of this study consisted of 621 housewives in Daegu area. The results were summarized as follows: The most often used foods of Pyebaeck refreshments included alcoholic drinks(80.0%), Bamgoim(73.8%), Daechugoim(73.4%). The refreshments were most often purchased from caterers(39.6%), and mainly used for marriages of their brothers and sisters(33.3%). The standard number of foods prepared was 7 to 10(42.2%). The most used container for Pyebaeck refreshments is bamboo basket(30.6%). 62.0% of the respondents needed Pyebaeck refreshments and the reason for refreshment preparation was mainly “because it is a Korean tradition”(82.3%) and the reason why most respondents do not think the Pyebaeck refreshments are necessary was “it's troublesome and complicated”(41.1%). The refreshments most frequently included were alcoholic drinks(63.7%) and Daechugoim(47.0%). Most of the respondents(84.9%) said that the Pyebaeck refreshments should be improved and 48.0% said the improvement method should consider the traditional tastes, flavors and arrangements fit to modem sense. Although following the traditions of Pyebaeck refreshments itself is difficult, the concept of Pyebaeck refreshments can develop into a modern concept with new meaning if we improve and adjust it in a way fit to modem lifestyles.

• Journal of Korean Home Economics Education Association
• /
• v.17 no.2
• /
• pp.239-255
• /
• 2005

The purpose of this study was to understand middle school Home Economics teachers' family value and needs on learning objectives of family life area, and to identify the relationship between the two. Data was collected from the survey mailed to the teachers responsible for family life area in $\lceil$Technology/Home Economics$\rfloor$ in middle schools in Korea. The collected 312 questionnaires were used for final analysis. SPSS/WIN program was used for calculating average, standard deviation, percentage, t-test, ANOVA with post-verification scheffe., and correlation analysis. Followings are the summary of the results of this study. Firstly, the family value of middle school Home Economics teachers was relatively modern. They had very modem sense of value in all of the sub-areas such as sense of value on marriage. on gender role. on children, on filial love, and familism. Secondly, regarding needs on family life area of learning objects of Home Economics teachers, the requirement on emancipatory system of action was the highest. technical system of action was the next, and Communicative System of Action was the lowest. Thirdly, in the relationship between the needs of teaming objects of family life area and the family value, the needs of technical and interpretive behavioral system had few things to do with the family value. However. the needs on teaming object needs of emancipatory system of action was higher as the family value was modern. The trend in the relationship with needs was same in all the sub-areas such as sense of value on marriage, on gender role, on children. on filial love, and familism. However, the family value and the achievement level of family life area goals did not show significant correlation. Fourthly, regarding the family value and the needs on teaming objectives of family life area of middle school Home Economics teachers, those who were female, who had certificates for Home Economics Teaching, who were young and who had less experiences in teaching had more modem family value and required more teaming objectives in emancipatory system of action. Considering the results of the study, it is needed to emphasize the learning objects of emancipatory system of action in family life education by inducing consensus on the proposition that Home Economics subject is a critical and practical subject. To do this. it is needed to provide Home Economics teachers with emancipatory interest and mature family value through educating and refreshing them. It is desirable to separate Technology and Home Economics so that certificated Home Economics teachers could teach family life area. In that case they can teach the subject in the point of practical criticism. If the area is to be taught by other subject teachers there should be enough understanding on the philosophy and nature of Home Economics subject beforehand.