• 한국자기공명학회논문지
• /
• 제3권2호
• /
• pp.140-148
• /
• 1999

Using 1H magnetic resonance spectroscopy (MRS), we quantitatively evaluated correlation representing linear relationship between the metabolite peak area ratios associated with poor shimming conditions. The inadequate shimming due to linear shim offsets directly affected overall MR spectral quality as well as peak area for each metabolite. Three major peaks such as N-acetylaspartate (NAA), creatine (Cr,) choline (Cho) were used as a reference for data analysis. Despite considerable variations of metabolite peak area, a significant correlation between the metabolite peak area ratios relative to Cr was established while the correlation between the peak area ratios relative to Cho and NAA was not. The present study suggested that metabolite peak area ratios based on the metabolite of Cr could be an acceptable quantification method even under the poor shimming in clinical MRS examination.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2008년도 학술발표회 논문집
• /
• pp.1111-1115
• /
• 2008

The relative magnitudes of the individual terms of the momentum equation are analyzed and compared by the analytical methods in open channel flow. The temporal variations of each term(local acceleration term, convective acceleration term, pressure force term, gravity force term, and friction force term) are analyzed for the influence factors to runoff expressed by the parameters of the momentum equation, stream slopes and roughness coefficients. The magnitudes of each term vary with the channel characteristics, especially when the roughness coefficients are dominant or for the mild stream slopes the pressure term can not be negligible. As a result of the characteristics of momentum equation in open channel flow, the acceleration terms are very small compared with the other terms. The magnitudes of local acceleration and convective acceleration offsets each other. The peak time of each term except the gravity term coincides with inflection point of the hydrograph rising limb each other.

• 한국국방경영분석학회지
• /
• 제31권1호
• /
• pp.14-25
• /
• 2005

Defense offset is considered to be all effective way of acquiring defense critical technologies and arms components as a counter-trade obligation ill defense acquisition contracts. Although arranging the offset contracts is wide]y perceived as necessary, there hardly exists an acceptable model of valuation of the offset technology. By undertaking the technology valuation approach and applying the option approach tn the offset program, we present an offset technology valuation model that maximizes social net benefit of the countries transferring the technology. This article applies our model to an actual case of defense technology transfer in the Republic of Korea. The contribution of this paper is in applying the option approach to the valuation of defense onset technology, providing for the additional flexibility to tile analysis. Our research suggests several policy implications that can be applied to the actual process of defense offsets. Our results elucidate managers' role and responsibilities in designing such a process by applying option approaches.

• Structural Engineering and Mechanics
• /
• 제21권5호
• /
• pp.519-537
• /
• 2005

A new generalized Bernoulli/Timoshenko beam-column element on a two-parameter elastic foundation is presented herein. This element is based on the exact solution of the differential equation which describes the deflection of the axially loaded beam resting on a two-parameter elastic foundation, and can take into account shear deformations, semi - rigid connections, and rigid offsets. The equations of equilibrium are formulated for the deformed configuration, so as to account for axial force effects. Apart from the stiffness matrix, load vectors for uniform load and non-uniform temperature variation are also formulated. The efficiency and usefulness of the new element in reinforced concrete or steel structures analysis is demonstrated by two examples.

• 한국의상디자인학회지
• /
• 제11권3호
• /
• pp.17-25
• /
• 2009

The purpose of this study is to help understanding of abstract patterns and to play a guideline's role in the development of designs and the prediction of trends for present and future fashion designers and textile designers. The summary of this study's results is like followings. Formative characteristics of abstract pattern in 2000's fashion are Impromptu, Anti-mechanism, Superimposing, Disorder. First, Impromptu is rebounce against uniformity, mechanism, man-created beauty Second, Anti-mechanism represents unfinishing, unbalance, inaccuracy and relates with each traditional of nation or ethnic group. Third, Presupposing transparency Superimposing offsets each patterns. So Their images are ambiguity, ununiformity, unequality, incompletion, uncertainty and so on. Fourth, Disorder breaks and ignores physical balance, rule, order and so on. These images represent uncertainty, freedom, naturality. From this result, I can interpret that these images are representing of humanism reacting about uniformity, mechanism, man-created beauty, completeness of modernism since the Industrial Revolution.

• 천문학회보
• /
• 제41권2호
• /
• pp.56.3-57
• /
• 2016

We present a recent progress on calibration of stellar isochrones based on a set of high-resolution spectra for 170 G- and K-type dwarfs in the solar neighborhood. We compare observed magnitudes of these stars in a number of broad passbands [UB(B_T)V(V_T)RIJHK] with model magnitudes generated using ATLAS9 synthetic library at the previously derived set of spectroscopic parameters. We find systematic offsets in colors from these passbands, which are mainly revealed as a function of effective temperature of stars. In order to remove these systematic color mismatches, we derive correction functions and apply them to the model spectra.

• Journal of Communications and Networks
• /
• 제7권3호
• /
• pp.284-293
• /
• 2005

A critical issue in applications involving networks of wireless sensors is their ability to synchronize, and mitigate the fading propagation channel effects. Especially when distributed 'slave' sensors (nodes) reach-back to communicate with the 'master' sensor (gateway), low power cooperative schemes are well motivated. Viewing each node as an antenna element in a multi-input multi-output (MIMO) multi-antenna system, we design pilot patterns to estimate the multiple carrier frequency offsets (CFO), and the multiple channels corresponding to each node-gateway link. Our novel pilot scheme consists of non-zero pilot symbols along with zeros, which separate nodes in a time division multiple access (TDMA) fashion, and lead to low complexity schemes because CFO and channel estimators per node are decoupled. The resulting training algorithm is not only suitable for wireless sensor networks, but also for synchronization and channel estimation of single- and multi-carrier MIMO systems. We investigate the performance of our estimators analytically, and with simulations.

• ETRI Journal
• /
• 제20권1호
• /
• pp.16-27
• /
• 1998

In this paper, we consider the acquisition performance of an IS-95 reverse link access channel slot as a function of system design parameters such as postdetection integration length and the number of access channel message block repetitons. The uncertainty region of the reverse link spreading codes compared to that of forward link is very small, since the uncertainty region of the reverse link is determined by a cell radius. Thus, the parallel acquisiton technique in the reverse link is more efficient than a serial acquisition technique in terms of implementation and of acquisition time. The parallel acquisition is achieved by a bank of N parallel I/Q noncoherent correlator are analyzed for band-limited noise and the Rayleigh fast fading channel. The detection probability is derived for multiple correct code-phase offsets and multipath fading. The probability of no message error is derived when rake combining, access channel message block combining, and Viterbi decoding are applied. Numerical results provide the acquisition performance for system design parameters such as postdetection integration length and number of access channel message block repetitions in case of a random access on a mobile station.

• ETRI Journal
• /
• 제31권4호
• /
• pp.466-468
• /
• 2009

In this letter, we propose a one-way ranging algorithm that is based on wireless synchronization with measured timestamps and clock frequency offsets. In our proposed algorithm, an active mobile node initiates a ranging procedure by transmitting a ranging frame, and the anchor nodes report their timestamps for the received ranging frame to a reference anchor node. The synchronization of a pair of nodes is provided with instantaneous time information, and the corresponding difference of distances can be calculated.

• 천문학회보
• /
• 제42권2호
• /
• pp.41.1-41.1
• /
• 2017

We present weak-lensing analysis of the merging galaxy cluster Abell 115 at z=0.197 based on Subaru i and V band images. As merging clusters often show, Abell 115's merging signatures include radio relics, double X-ray peaks, and large offsets between the cluster member galaxies and the X-ray distributions. A weak-lensing study provides underlying dark matter distribution, the key information to determine the complex merging scenario of the cluster. In this work, we present 2D mass reconstruction of the cluster, which reveals two distinct mass peaks consistent with galaxy distributions. We measure the first weak-lensing mass of each subcluster. Our weak-lensing total mass estimate is a few factors lower than the published dynamical mass obtained from velocity dispersion. This large mass discrepancy may be attributed to a significant departure from dynamical equilibrium. We also re-analyze the archival chandra data and find that the result is consistent with weak-lensing mass.