• KSBB Journal
• /
• v.15 no.5
• /
• pp.438-443
• /
• 2000

Continuous processes using immobilized yeast were investigated in order to shorten beer maturation time. Three silica-based ceramic media and one cellulose-based medium were used. Diacetyl (DA) was one of the most distinctive compounds causing immature flavors. Heat treatment of green beer (GB) to convert a-acetolactate to DA was essential to shorten the time for beer maturation. The longer heat treatment time was needed at the lower temperature. Oxygen concentration in GB had a large influence on the conversion of a-acetolactate to DA. The lower the oxygen concentration in GB, the lower conversion ratio to DA. Heat treated GB was fed continuously to four kinds of immobilized yeast columns. DA concentration after immobilization columns was reduced to less than 0.1ppm at $3∼5^{\circ}C$ 180∼150 minutes retention time in all columns tested. This concentration is enough to fit the quality speification of commercialized product. Formation of a-acetolactate from residual sugars was higher in ceramic media column than cellulose media cloumn. The taste of beers from test processes were not the same as that of traditionally produced beer, but no off-flavors were detected in test samples, which shows that immobilized yeast columns have potentials as rapid processes for beer maturation.

• Journal of the Korea Concrete Institute
• /
• v.17 no.4 s.88
• /
• pp.551-558
• /
• 2005

The setting and hardening of concrete is accompanied with nonlinear temperature distribution caused by development of hydration heat of cement. Especially at early ages, this nonlinear distribution has a large influence on the crack evolution. As a result, in order to predict the exact temperature history in concrete structures it is required to examine thermal properties of concrete. In this study, the convection heat transfer coefficient which presents thermal transfer between surface of concrete and air, was experimentally investigated with variables such as velocity of wind, curing condition and ambient temperature. At initial stage, the convection heat transfer coefficient is overestimated by the evaporation quantity. So it is essential to modify the thermal equilibrium considered with the boiling effect. From experimental results, the convection heat transfer coefficient was calculated using equations of thermal equilibrium. Finally, the prediction model for equivalent convection heat transfer coefficient including effects of velocity of wind, curing condition, ambient temperature and boiling effects was theoretically proposed. The convection heat transfer coefficient in the proposed model increases with velocity of wind, and its dependance on wind velocity is varied with curing condition. This tendency is due to a combined heat transfer system of conduction through form and convection to air. From comparison with experimental results, the convection heat transfer coefficient by this model was well agreed with those by experimental results.

• Journal of the Korea Convergence Society
• /
• v.8 no.4
• /
• pp.231-237
• /
• 2017

This study investigated differences in perception by 240 males in their teens, 20s, 30s, and 40s residing in Seoul, Incheon, and Gwangju about seven items for male makeup, and analyzed makeup items preferred by men, perception about male makeup users, and relationship between success and appearance, thereby providing basic materials to activate the beauty market for males and developing goods for male users. The result was that most males thought the influence of their appearance on their social success was great and in particular, 23.3% of respondents thought that their appearance affected their success by 50% or higher percentage. The items most preferred by the respondents were concealers, color lotions, and BB creams; 60.8% considered them positive. This showed that basic color cosmetics had already been established as one of the essential goods for men. In contrast, the respondents had slightly negative perception about items like mascaras, eyeliners, and eyeshadows. Overall, those who were young, unmarried, and city dwellers had positive perception about such cosmetics by and large. The above data will be able to be used to develop various makeup goods for male consumers oriented toward success and implement diverse marketing strategies, thereby activating the beauty market for males.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.2B
• /
• pp.100-107
• /
• 2007

Recently, a study of BcN(Broadband convergence Network) is progressing continuously, and it is important to improve the quality of the service according to subscribers because a scale of network is about to be larger. It is more important to manage QoS(Quality of Service) of all subscribers in layer 2 than layer 3 network since managing it in layer 3 network cost both additional processes and large hardware. Moreover, QoS based on Best-Effort service has been developed because tots of subscribers should use limited resource in BcN. However, they want to be supplied with different service even though they pay more charge. Therefore, it is essential to assign the different bandwidth to subscribers depending on their level of charge. The method of current Rate Limiter limits the bandwidth of each port that does not offer fair service to subscribers. The Rate Limiter proposed in this paper limits bandwidth according to each subscriber. Therefore, subscribers can get fair service regardless of switch structure. This new Rate Limiter controls the bandwidth of subscribers according to the information of learning subscriber and manages maximum performance of Ethernet switch and QoS.

• Journal of Korean Society of Forest Science
• /
• v.106 no.1
• /
• pp.1-9
• /
• 2017

Forest harvest as large scale artificial disturbance makes edge environment in both clear-cutted and forested habitat. To clarify the development and recovery process of forest edge after disturbances is essential to understand vegetation responses and landscape level consequences such as edge-distance. In Korea, after clear-cutting, edge-related changes of environment and vegetation was not clarified yet. In Korean red pine (Pinus densiflora) forest, by applying space-for-time approach (sites with undisturbed and 1, 3, 10, 16 yr after cutting), the edge-related change of plant abundance and abiotic factors were determined for 20 line-transect (60 m) and 340 ($1m{\times}5m$) quadrats, and clarified depth and duration of the disturbance. Immediately after edge formation, within 15m form the edge, biotic and abiotic factors such as cover, richness, canopy openness, temperature and moisture content exhibited larger changes compared to forest interior. Plant abundance and abiotic variables were stabilized at the level of forest inside within 16 yr and 10 yr after edge creation, respectively. Woody (tree and shrub) species generally was showed larger increment with proximity to edge than did herb or graminoid species. In addition, negative interactions between woody and herbaceous species were detected during the period of forest edge closure. Our results suggested that depth of forest edge formed by clear-cutting of Korean red pine forest was at least from 15 m to 20 m and edge effect were likely sustained more than 16 years. As the first empirical study on edge-distance between two contrast habitats of clear-cutted and adjacent forest in South Korea, the analytical reality on landscape structure and habitat patches can be improved.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.41 no.4
• /
• pp.307-312
• /
• 2017

Laser cladding has some advantages compared to conventional cladding technologies such as arc welding and thermal spraying. Laser cladding produces a metallurgically well-bonded clad layer with a lower dilution ratio and few defects. Based on the characteristics of a 1-pass clad layer with many parameters, which were investigated in a previous report, it was found that it was essential to overlap a 1-pass clad layer when cladding a large area. In this study, the shape differences of multi-pass clad layers with various overlapping ratios were compared. Then, the alloying element distribution of cladding with a certain overlapping ratio was investigated using EDS and EPMA. As the overlapping ratio increased, the length of the clad decreased and its height increased. In addition, the height of the multi-pass cladding was higher than that of the 1-pass cladding under the same condition. The Fe content of the highly diluted first clad was found to be approximately 20 % in an element analysis. However in the area outside of the first clad, the Fe content was decreased to 10 % as a result of minimum dilution, and a uniform distribution of elements was found.

• Journal of KIISE:Databases
• /
• v.30 no.5
• /
• pp.507-520
• /
• 2003

In this paper, an automatic construction method of theme melody index for large music database and an associative content-based music retrieval mechanism in which the constructed theme melody index is mainly used to improve the users' response time are proposed. First, the system automatically extracted the theme melody from a music file by the graphical clustering algorithm based on the similarities between motifs of the music. To place an extracted theme melody into the metric space of M-tree, we chose the average length variation and the average pitch variation of the theme melody as the major features. Moreover, we added the pitch signature and length signature which summarize the pitch variation pattern and the length variation pattern of a theme melody, respectively, to increase the precision of retrieval results. We also proposed the associative content-based music retrieval mechanism in which the k-nearest neighborhood searching and the range searching algorithms of M-tree are used to select the similar melodies to user's query melody from the theme melody index. To improve the users' satisfaction, the proposed retrieval mechanism includes ranking and user's relevance feedback functions. Also, we implemented the proposed mechanisms as the essential components of content-based music retrieval systems to verify the usefulness.

• Journal of Intelligence and Information Systems
• /
• v.20 no.1
• /
• pp.1-14
• /
• 2014

Both researchers and practitioners are showing an increased interested in interactive exhibition services. Interactive exhibition services are designed to directly respond to visitor responses in real time, so as to fully engage visitors' interest and enhance their satisfaction. In order to install an effective interactive exhibition service, it is essential to adopt intelligent technologies that enable accurate estimation of a visitor's emotional state from responses to exhibited stimulus. Studies undertaken so far have attempted to estimate the human emotional state, most of them doing so by gauging either facial expressions or audio responses. However, the most recent research suggests that, a multimodal approach that uses people's multiple responses simultaneously may lead to better estimation. Given this context, we propose a new multimodal emotional state estimation model that uses various responses including facial expressions, gestures, and movements measured by the Microsoft Kinect Sensor. In order to effectively handle a large amount of sensory data, we propose to use stratified sampling-based MRA (multiple regression analysis) as our estimation method. To validate the usefulness of the proposed model, we collected 602,599 responses and emotional state data with 274 variables from 15 people. When we applied our model to the data set, we found that our model estimated the levels of valence and arousal in the 10~15% error range. Since our proposed model is simple and stable, we expect that it will be applied not only in intelligent exhibition services, but also in other areas such as e-learning and personalized advertising.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.12 no.3
• /
• pp.210-218
• /
• 2002

This paper proposes an efficient separation method of the composite images by using independent component analysis(ICA) based on neural networks of the approximate learning algorithm. The Proposed learning algorithm is the fixed point(FP) algorithm based on Secant method which can be approximately computed by only the values of function for estimating the root of objective function for optimizing entropy. The secant method is an alternative of the Newton method which is essential to differentiate the function for estimating the root. It can achieve a superior property of the FP algorithm for ICA due to simplify the composite computation of differential process. The proposed algorithm has been applied to the composite signals and image generated by random mixing matrix in the 4 signal of 500-sample and the 10 images of $512{\times}512-pixel$, respectively The simulation results show that the proposed algorithm has better performance of the learning speed and the separation than those using the conventional algorithm based method. It also solved the training performances depending on initial points setting and the nonrealistic learning time for separating the large size image by using the conventional algorithm.

• The Journal of Engineering Geology
• /
• v.27 no.2
• /
• pp.153-164
• /
• 2017

The geological factors for causing ground subsidence are very diverse. It can be affected by any geological or extrinsic influences, and even within the same geological factor, the soil depression impact factor can be determined by different physical properties. As a result of reviewing a large number of papers and case histories, it can be seen that there are seven categories of ground subsidence factors. The depth and thickness of the overburden can affect the subsidence depending on the existence of the cavity, whereas the depth and orientation of the boundary between soil and rock are dominant factors in the ground composed of soil and rock. In case of soil layers, more various influencing factors exist such as type of soil, shear strength, relative density and degree of compaction, dry unit weight, water content, and liquid limit. The type of rock, distance from the main fracture and RQD can be influential factors in the bedrock. When approaching from the hydrogeological point of view, the rainfall intensity, the distance and the depth from the main channel, the coefficient of permeability and fluctuation of ground water level can influence to ground subsidence. It is also possible that the ground subsidence can be affected by external factors such as the depth of excavation and distance from the earth retaining wall, groundwater treatment methods at excavation work, and existence of artificial facilities such as sewer pipes. It is estimated that to evaluate the ground subsidence factor during the construction of underground structures in urban areas will be essential. It is expected that ground subsidence factors examined in this study will contribute for the reliable evaluation of the ground subsidence risk.