• ETRI Journal
• /
• v.39 no.5
• /
• pp.729-736
• /
• 2017

This work investigates secure cluster-aided multi-hop randomize-and-forward networks. We present a hop-by-hop multi-hop transmission scheme with relay selection, which evaluates for each cluster the relays that can securely receive the message. We propose an analytical model to derive the secure connectivity probability (SCP) of the hop-by-hop transmission scheme. For comparison, we also analyze SCPs of traditional end-to-end transmission schemes with two relay-selection policies. We perform simulations, and our analytical results verify that the proposed hop-by-hop scheme is superior to end-to-end schemes, especially with a large number of hops or high eavesdropper channel quality. Numerical results also show that the proposed hop-by-hop scheme achieves near-optimal performance in terms of the SCP.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.11 no.1
• /
• pp.215-236
• /
• 2017

Obtaining accurate location information is important in practical applications of wireless sensor networks (WSNs). The distance vector hop (DV-Hop) is a frequently-used range-free localization algorithm in WSNs, but it has low localization accuracy. Moreover, despite various improvements to DV-Hop-based localization algorithms, maintaining a balance between high localization accuracy and good stability and convergence is still a challenge. To overcome these shortcomings, we proposed an improved DV-Hop localization algorithm based on the bat algorithm (IBDV-Hop) for WSNs. The IBDV-Hop algorithm incorporates optimization methods that enhance the accuracy of the average hop distance and fitness function. We also introduce a nonlinear dynamic inertial weight strategy to extend the global search scope and increase the local search accuracy. Moreover, we develop an updated solutions strategy that avoids premature convergence by the IBDV-Hop algorithm. Both theoretical analysis and simulation results show that the IBDV-Hop algorithm achieves higher localization accuracy than the original DV-Hop algorithm and other improved algorithms. The IBDV-Hop algorithm also exhibits good stability, search capability and convergence, and it requires little additional time complexity and energy consumption.

• Journal of the Korean Society of Costume
• /
• v.60 no.6
• /
• pp.62-73
• /
• 2010

The purpose of this thesis is to make an effective Korean Hip Hop culture and suggest a new style direction in classifying the types of fashion styles of the Hip Hop musicians and studying their features. They are surveyed in stage costumes, hair styles, make-ups, accessaries, and total fashion styles, and then classified into Normal Hip Hop Style, Casual Hip Hop Style, Sporty Hip Hop Style, Mix & Match Hip Hop Style, and Classical Hip Hop Style. The results of the study are as follows: First, Normal Hip Hop Style is the most general and universal Hip Hop fashion type. They wear clothes in bigger sizes and exaggeratively. And also a cornrow hair style, a tattoo, and a piercing represent marked individualities. Second, Casual Hip Hop Style is more active and practical than Normal Hip Hop Style. Their blue jeans and T-shirts express more simple and polished style. And also they make variable fashion styles and hair styles such as a cornrow hair and a buzz cut. Third, Sporty Hip Hop Style is from B-boy's clothes when they do active and violent break dancing. As NBA basketball games are popular, they wear training clothes, breeches, big T-shirts, and jumpers & caps on embroidered sport team's names. Their hair style is short or natural and also they have caps or hoods to present active mood. Fourth, Mix & Match Hip Hop Style is existed variable elements in one style. The typical type of this style is jacket & blue jean. It is characterized by dress shirts, neck ties, blue jeans, sneakers, beards, and moustaches. Fifth, Classical Hip Hop Style is from African Americans. They try to express assimilated appearance of Anglo-Saxons. They wear black suits, shoes, hats, and sunglasses to represent formality and elegance. In the above results, there are variable fashion styles in one Hip Hop music genre and also fashion style is changed with musical inclination. This thesis is an important guide to produce variable and creative Hip Hop fashion styles in Korean Hip Hop culture.

• Journal of the Korean Society of Costume
• /
• v.65 no.4
• /
• pp.61-75
• /
• 2015

This research aims to analyze the prep-hop fashion, which is an original look created through the convergence of the hip-hop and preppy look, and identify the design characteristics of the prep-hop fashion. The style mixes the fashion of what was traditionally a lower-class look with the upper class. The design characteristics are as follows: First, the prep-hop fashion expresses slim, casual and sophisticated look with items and silhouettes. The items are categorized into jackets, shirts and pants. The prep-hop jackets provides a casual look to its wearer unlike the jackets of preppy or conservative looks. Slim suits show different meanings and features depending on the changes in the time and culture despite the continued use of the items. Second, the colors of the prep-hop fashion include overall basic colors used in the preppy look and hip-hop fashion. The aesthetic values of the colors express pleasant color images different from the conservative and resistant images expressed in the preppy and hip-hop style before the convergence, respectively. Third, the materials and patterns are expressed in a unique way to fulfill the emotional needs that are considered vital to contemporary fashion. The materials in the prep-hop fashion extend the ranges of usage by using the materials with unexpectedness broken out of general range of usage. While the use of the patterns is one of the methods to demonstrate that the prep-hop fashion is created by the convergence between hip-hop fashion and preppy look, the meaning concludes pleasantness and casualness different from the past. Fourth, the prep-hop fashion is mainly composed of hip-hop fashion accessories, which express the authenticity of the hip-hop fashion to protect the non-mainstream characteristics. The design characteristics of the prep-hop fashion pursue the individuality of the contemporary fashion, which lacks originality due to commercialization. The development of the prep-hop fashion, as a new form that combined contrasting genres and trends, is expected to develop more publicly.

• Korean Journal of Applied Biomechanics
• /
• v.24 no.4
• /
• pp.367-373
• /
• 2014

Most athletes execute rhythmic hop as a preparatory motion in Taekwondo sparring. The purpose of this study was to investigate the effect of rhythmic hop on the response times and kicking velocities of Taekwondo kicks. Twelve male elite Taekwondo athletes performed a roundhouse kick and a back kick as fast as possible immediately after seeing an external stimulus in rhythmic hop and in no hop, respectively. The three-dimensional marker data of the whole body were measured at sampling rate of 200 Hz. Paired t-tests were used to compare dependent measures between hop and no hop conditions. Results indicated that the rhythmic hop did not affect response time statistically but improved the kicking velocity significantly than no hop did. Different instants of detecting an external stimulus in rhythmic hop for the back kick showed significantly different response times. Conclusively, rhythmic hop is recommendable for the purpose of kicking velocity, but not for the purpose of response time. Athletes should be careful in executing rhythmic hop as their preparatory motions for the back kick, since the response time could be shortened or lengthened according to the instant of detecting an external stimulus.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.18 no.3
• /
• pp.129-144
• /
• 2016

The purpose of this study is to identify current trends in hip-hop fashion in korea and how they are influenced by musical characteristics of female hip-hop. This study considers the relationship between female hip-hop music and their fashion through the history of hip-hop. Data has been collected and analyzed from broadcastings, performances, music videos, and album jackets of female musicians who appeared in the cable television program 'Unpretty Rapstar' by MNET during two seasons in 2015. "Unpretty Rapstar" is the first program to focus on the music and fashion of female Korean hip-hop musicians. For the theoretical review, this article examines books and journal articles, which provide insight into the history and formation of hip-hop. It also analyzes the hip-hop styles of female musicians in Korea through Hiphopplaya.com, an Internet site specializing in hip-hop. the results of the analysis of the fashion of female Korean hip hop musicians is as follows: The characteristics of the styles of female hip-hop artists come out of Glam Style, which emphasizes femininity, but is also composed of a practical and dynamic street casual style. Most of the clothes are skinny jeans and sweat suits with vertical and slim-fit silhouettes or stadium jackets and jersey jackets with oversized silhouettes. The main colors of these outfits are prominently yellow and red with darker grayish tones, but also include natural achromatic colors.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.8 no.1
• /
• pp.127-136
• /
• 2006

These researches discussed promotions and effectiveness in the area of star marketing production, copying, advertising, and expenditure on clothes. The thesis is refreshing in the way it deals with analysis of strategical changes in the fashion of entertainers asia cultural industry developed. I specially focused on comparing and analyzing the changes in style of Hip Hop fashion from the period of inferior culture to the period in which their fashion is highly respected. Also, I'd like to study the influence of the fashion to Korean Hip Hop artists. The Hip Hop musicians developed their styles from underdog images of Hip Hop to glamourous and luxurious styles along with modeling in various magazines appealing sexually. In Korea, Seven and Hyori Lee are showing new and changed styles that are different from the past to their fans. The Hip Hop style now is showing with unimaginably luxurious styles as opposed to its original image. With their pursuance of ostentatious and luxurious styles Hip Hop was reborn as new Glam style. Old Hip Hop styles such as ripped jeans, safety pins, graffiti, and loose and exaggerated silhouette give inspirations to many worldly known designers and their collection. Hip Hop that used to be a branch of a low culture was able to grow to the culture of luxuries via the development the media and improvement of lives and the level of consciousness of the middleclass. Music stars with luxurious Hip Hop fashion influenced coming of a new musical genre and Korean musicians largely. I hope this research can help developing the unique low-culture and creating new trend in the field of entertainers' fashion.

• The Korean Journal of Physiology and Pharmacology
• /
• v.16 no.3
• /
• pp.187-192
• /
• 2012

In the present study, the antinociceptive profiles of hop extract were characterized in ICR mice. Hop extract administered orally (from 25 to 100 mg/kg) showed an antinociceptive effect in a dose-dependent manner as measured in the acetic acid-induced writhing test. Antinociceptive action of hop extract was maintained at least for 60 min. Moreover, cumulative response time of nociceptive behaviors induced with intraplantar formalin injection was reduced by hop extract treatment during the 2nd phases. Furthermore, the cumulative nociceptive response time for intrathecal injection of substance P ($0.7{\mu}g$) or glutamate ($20{\mu}g$) was diminished by hop extract. Intraperitoneal pretreatment with naloxone (an opioid receptor antagonist) attenuated antinociceptive effect induced by hop extract in the writhing test. However, methysergide (a 5-HT serotonergic receptor antagonist) or yohimbine (an ${\alpha}_2$-adrenergic receptor antagonist) did not affect antinociception induced by hop extract in the writhing test. Our results suggest that hop extract shows an antinociceptive property in various pain models. Furthermore, the antinociceptive effect of hop extract may be mediated by opioidergic receptors, but not serotonergic and ${\alpha}_2$-adrenergic receptors.

• Korean Journal of Food Science and Technology
• /
• v.52 no.3
• /
• pp.296-303
• /
• 2020

Hop-resistant lactic acid bacteria (LAB) are well-known, major beer-spoilage bacteria. The hop-gradient agar containing ethanol (c-HGA+E) method has been used to examine hop-resistance of beer-spoilage LAB. However, the selection of beer-spoilage bacteria by the c-HGA+E method is either too selective or too inclusive. Furthermore, it is accompanied by a complicated experimental procedure, high-cost and time. To overcome these disadvantages, the modified hop-gradient agar with ethanol (m-HGA+E) method was developed. The most remarkable modifications were the shape of the petri dish and the inoculation method for bacteria. The efficiency and validation of the m-HGA+E approach were proven by the formation of colonies at different hop concentrations in the bottom layer, co-culture with the bacteriocin producer and by PCR detection of hop-resistant genes. This study demonstrated that m-HGA+E is a rapid, economical, and easy method to monitor potential hop-resistant beer-spoilage LAB during the beer brewing process.

• The Research Journal of the Costume Culture
• /
• v.19 no.2
• /
• pp.416-429
• /
• 2011

Most of precedent studies related to hip hop culture and fashion, which have been conducted till now were progressed under only theoretical background of hiphop, not the changed status of hiphop currently. Practical studies explaining the status of hip hop in popular culture, especially, the area of popular fashion are insufficient. Therefore, this study was conducted by focusing on cultural characteristics and musical characteristics by the stream of period, for which concept hip hop is accepted to people currently and which effect it makes on the area of fashion. Especially, the study was progressed by dividing periodical background into before and after the 2000s because there was the most noticeable change for the genre of hip hop in that period. Because of the appearance of 'Alternative hip hop' which is a sub-genre of hip hop music, hip hop music was changed to be more popular. Also, hip hop fashion also showed big changes. Hip hop fashion before 2000s had showed poor conditions, resistance, complex and alienation of them by their fashion. On the other hand, hip hop fashion after 2000s also showed popular characteristics because of high-level environment and social status. This study intended to understand and grasp hip hop as a kind of cultural situation coexisted by many-sided characteristics as well as redefine the changed concept and contents of new hip hop currently.