• Communications of the Korean Mathematical Society
• /
• v.32 no.2
• /
• pp.233-260
• /
• 2017

Let R be a factorial domain. In this work we investigate the connections between the arithmetic of Int(R) (i.e., the ring of integer-valued polynomials over R) and its monadic submonoids (i.e., monoids of the form {$g{\in}Int(R){\mid}g{\mid}_{Int(R)}f^k$ for some $k{\in}{\mathbb{N}}_0$} for some nonzero $f{\in}Int(R)$). Since every monadic submonoid of Int(R) is a Krull monoid it is possible to describe the arithmetic of these monoids in terms of their divisor-class group. We give an explicit description of these divisor-class groups in several situations and provide a few techniques that can be used to determine them. As an application we show that there are strong connections between Int(R) and its monadic submonoids. If $R={\mathbb{Z}}$ or more generally if R has sufficiently many "nice" atoms, then we prove that the infinitude of the elasticity and the tame degree of Int(R) can be explained by using the structure of monadic submonoids of Int(R).

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.10 no.3
• /
• pp.367-375
• /
• 2018

The present paper considers the contact between energy-saving device of ice-class vessel and ice block. The main objective of this study is to clarify the tendency of the ice impact force and the structural response as well as interaction effects of them. The contact analysis is performed by using LS-DYNA finite element code. The main collision scenario is based on Finnish-Swedish ice class rules and a stern duct model is used as an energy-saving device. For the contact force, two modelling approaches are adopted. One is dynamic indentation model of ice block based on the pressure-area curve. The other is numerical material modelling by LS-DYNA. The authors investigated the sensitivity of the structural response against the ice contact pressure, the interaction effect between structure and ice block, and the influence of eccentric collision. The results of these simulations are presented and discussed with respect to structural safety.

• Journal of KSNVE
• /
• v.9 no.6
• /
• pp.1227-1233
• /
• 1999

Modern technology depends on the reliability of extremely high technology equipments. In the production of semiconductor wafer, optical and electron microscopes, ion-beam, laser device must maintain their alignments within a nanometer. This equipment requires a vibration free environment to provide its proper function. Especially, lithography and inspection devices, which have sub-nanometer class high accuracy and resolution, have come to necessity for producing more improved giga and tera class semiconductor wafers. This high technology equipments require very strict environmental vibration standard, vibration criteria, in proportion to the accuracy of the manufacturing, inspecting devices. This paper deals with the structural dynamic design in high class semiconductor factory in order to be satisfied more strict vibration criteria for high sensitive equipment.

• Proceedings of the Korean Society for Language and Information Conference
• /
• 2007.11a
• /
• pp.67-75
• /
• 2007

This paper presents the architectural aspects of the phrase analyzer that attempts to recognize phrases and identify the functional roles in the sentences in formal Japanese documents. Since the object of interest is a phrase, the current system, designed in an object-oriented architecture, contains the Phrase class, and makes use of the linguistic generalization about languages with Case markers that a phrase, whether a noun phrase, a verb phrase, a postposition (or preposition) phrase or a clause phrase, can be separated into the content and the function components. Without a dictionary, and drawing on the orthographic information on the words to parse, it also contains a class that identifies the types of characters, a class representing grammar, and a class playing the role of a controller. The system has a simple and intuitive structure, externally and internally, and therefore is easy to modify and extend.

• Journal of electromagnetic engineering and science
• /
• v.11 no.3
• /
• pp.161-165
• /
• 2011

In this paper, a high-efficiency DC-AC converter is used for wireless energy transmission. The DC-AC convertter is implemented by combining the oscillator and power amplifier. Given that the conversion efficiency of a DC-AC converter is strongly affected by the efficiency of the power amplifier, a high-efficiency power amplifier is implemented using a class-E amplifier structure. Also, because of the low output power of the oscillator connected to the input stage of the power amplifier, a high-gain two-stage power amplifier using a drive amplifier is used to realize a high-output power DC-AC converter. The high-efficiency DC-AC converter is realized by connecting the oscillator to the input stage of the high-gain high-efficiency two-stage class-E power amplifier. The output power and the conversion efficiency of the DC-AC converter are 40.83 dBm and 87.32 %, respectively, at an operation frequency of 13.56 MHz.

• 한국정보통신설비학회:학술대회논문집
• /
• 2008.08a
• /
• pp.403-408
• /
• 2008

In this paper, the high efficiency and linearity Doherty power amplifier using DGS and adaptive bias technique has been designed and realized for 2.3GHz WiBro applications. The Doherty amplifier has been implemented us-ing silicon MRF 281 LDMOS FET. The RF performances of the Doherty power amplifier (a combination of a class AB carrier amplifier and a bias-tuned class C peaking amplifier) have been compared with those of a class AB amplifier alone, and conventional Doherty amplifier. The Maximum PAE of designed Doherty power amplifier with DGS and adaptive bias technique has been 36.6% at 34.01dBm output power. The proposed Doherty power amplifier showed an improvement 1dB at output power and 7.6% PAE than a class AB amplifier alone.

• Korean Journal of Remote Sensing
• /
• v.21 no.5
• /
• pp.417-423
• /
• 2005

A fuzzy approach using an EM algorithm for image classification is presented. In this study, a double compound stochastic image process is assumed to combine a discrete-valued field for region-class processes and a continuous random field for observed intensity processes. The Markov random field is employed to characterize the geophysical connectedness of a digital image structure. The fuzzy classification is an EM iterative approach based on mixture probability distribution. Under the assumption of the double compound process, given an initial class map, this approach iteratively computes the fuzzy membership vectors in the E-step and the estimates of class-related parameters in the M-step. In the experiments with remotely sensed data, the MRF-based method yielded a spatially smooth class-map with more distinctive configuration of the classes than the non-MRF approach.

• Korean Institute of Interior Design Journal
• /
• v.16 no.2 s.61
• /
• pp.217-224
• /
• 2007

The ratio of the aged population over 65 in Korea comprises 5.7% of the total population in 1995, and 7.1% in 2001, and it is expected that it will be 14% in year 2023. Also, owing to the appearance of various layers of the aged, it is necessary to prepare various programs and facilities for the aged who are healthy and economically capable in order for them to spend their life in an abundant and rewarded way. Andthere is a rising necessity not only to recognize the value of existence for the existing elderly welfare facilities but to prepare new elderly welfare facilities considering comprehensive elderly welfare as well. Especially, even though elderly welfare centers continue to provide for the aged both in a low-income class and a common class various service programs and activity programs, there still is a poor structure in terms of spatial dimension in detail to comply the service. Accordingly, we believe that it is necessary to have a comparative study on elderly welfare centers in Japan as elderly welfare facility that advances about 30 years ahead. For this purpose, this study compared the spatial structures of application programs according to facility regulations and their gross spatial classification focusing on elderly welfare centers in Japan and those of Korea. Based on this, this study intends to present basic materials for interior space planning when establishing elderly welfare centers founded on space dimension and structure along with the gross space in elderly welfare centers in Korea in the future.

• Journal of Korean Society of Forest Science
• /
• v.94 no.5 s.162
• /
• pp.321-329
• /
• 2005

Based on the data representing four typical Korean pine forest types, the age structure, DBH distribution, species composition, and forking rule were systemically analyzed for old-growth Korean pine forest in Liangshui Nature Reserve, northeast China. The age structure of Korean pine trees was strongly uneven-aged with one dominated peak following normal distribution, and age of trees varied from 100 to 180 years within a stand. The DBH and height differences in same age class (20 years) varied from 28 cm~64 cm and 5 to 20 m, respectively. Many conifer and hard wood species, such as spruce, fir, costata birch, basswood, oak, and elm, were mixed with dominated trees of Korean pine. The canopy of the old-growth Korean pine forest can be divided into two layers, and differences of mean age and height between Layer I and Layer II were ranged 80~150 years and 7~13 m, respectively. The Weibull function was used to model the diameter distribution and performed well to describe size-class distribution either with a single peak in over-story canopy and inverse J-shape in under-story canopy for old-growth Korean pine stands. The forking height of Korean pine trees ranged from 16m to 24 m (mean 19.4 m) and tree age about 120 to 160 years old. The results will provide a scientific basis to protect and recover the ecosystem of natural old-growth Korean pine and also provide the model in management of Korean pine plantation.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.15 no.4
• /
• pp.479-485
• /
• 2005

Recently, computing technology requires intelligent system structures for context-awareness in ubiquitous computing environment. An intelligent system for context-awareness is based on agents, and need sensor information to recognize users and frames to support service. Therefore, this paper proposes the structure of 3-tier context-awareness processing server/client that can connect dynamically with each sensor and service, and support various context stably The structure of a proposal system is composed of a client class that recognizes uses' context information, a server class that processes realized context information by an application processing agent, and a management server that manages these two classes. Also, in this structure users information is composed of dynamic profile to support exquisite service.