• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.368-368
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• 2008

Ion implantation has been widely developed during the past decades to become a standard industrial tool. To comply with the growing needs in ion implantation, innovative technology for the control of ion beam parameters is required. Beam current, beam profile, ion fractions are of great interest when uniformity of the implant is an issue. Especially, it is important to measure the spatial distribution of beam power and also the energy distribution of accelerated ions. This energy distribution is influenced by the proportion of mass for ion in the plasma generator(ion source) and by charge exchange and dissociation within the accelerator structure and also by possible collective effects in the neutralizer which may affect the energy and divergence of ions. Hydrogen atom has been the object of a good study to investigate the energy distribution. Hydrogen ion sources typically produce multi-momentum beams consisting of atomic ion ($H^+$) and molecular ion ($H_2^+$ and $H_3^+$). In the beam injector, the molecular ions pass through a charge-exchanges gas cell and break up into atomic with one-half (from $H_2^+$) or one-third (from $H_3^+$) according to their accelerated energy. Burrell et al. have observed the Doppler shifted lines from incident $H^+$, $H_2^+$, and $H_3^+$ using a Doppler shift spectroscopy. Several authors have measured the proportion of mass for hydrogen ion and deuterium using an ion source equipped with a magnetic dipole filter. We developed an ion implanter with 50-KeV and 20-mA ion source and 100-keV accelerator tube, aiming at commercial uses. In order to measure the proportion of mass for ions, we designed a filter system which can be used to measure the ion fraction in any type of ion source. The hydrogen and helium ion species compositions are used a filter system with the two magnets configurations.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.7
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• pp.685-691
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• 2003

This paper newly analyzes the effect of the phase noise in the frequency synthesizer on the performance of SFH/M-NCFSK system by standard frequency deviation(equation omitted) when noncoherent FSK demodulation of the square-law detector is considered. We derive the SER in the SFH system and analyze the effect of phase noise on the SFH/M-NCFSK system performance according to the hopping frequency spacing (1/T$\_$h/) and the variation of the standard frequency deviation (equation omitted). The required SNR is about 13.4 dB to meet Ps=10$\^$-3/ when the standard frequency deviation is about 4.0 Hz and the hopping frequency spacing (1/T$\_$h/) in the SFH/2-NCFSK system is 30. So, there is about 2.4 dB power penalty than the phase noise-free system. If the hopping frequency spacing 1/T$\_$h/ is under 30, the error floor may happen and SER considerably grows up. We show that the analytic results closely match with the simulation results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.10
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• pp.1150-1156
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• 2007

In this paper, two novel subsurface antennas for remote management of underground facilities using PCS and cellular wireless network are proposed. The proposed subsurface antenna is a dual band circular patch which is inserted and molded for the protection of the antenna into a metal such as a manhole cover. The antenna is designed considering the resonant frequency shift of the antenna due to the insertion and molding. The measured return loss and receiving power of the fabricated antenna comparison with a dipole shows that two proposed subsurface antenna can be used for remote management of underground facilities using PCS and cellular systems.

• Journal of the Economic Geographical Society of Korea
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• v.16 no.1
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• pp.50-70
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• 2013

The creation of new economic paradigm shift in creative economy age have influence on the characteristics of social networks and space, it leads to the formation of new relationship in space depending on social network service development. In this paper, it gives a name to 'social network resource' the power affecting these features and to find the meaning of spatial changes in the economic geography perspectives. 'Social network resource' shows the characteristics of openness, sharing, participation and cooperation, with features of encompassing all the features of local and global characteristics in space. This features are related the meaning of 'trans-locality' and can be found in the case of 'WikiSeoul.com (http:/www.wikiseoul.com)', Seoul's social knowledge sharing web platform. In particular, physical resources, human resources, information resources, and the characteristics of the relationship as a resource features was found and these features appear in space is projected to the space of social relations, it reflects the characteristics of qualitative space regarding social network resource.

• The Journal of the Korea Contents Association
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• v.8 no.4
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• pp.108-116
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• 2008

Recently the advent of web 2.0 era is an important trend in the business environmental change. Web 2.0 era means users' active participation, share, and openness, develop 'Internet penetration into everyday life,' and change many aspects of our society. web 2.0 has been making these following changes in the socioeconomic aspects: 1) acceleration of system shift to a small quantity of multi-species production system 2) growing influence of on-line channel/information to consumers 3) various minorities' power increase in the socioeconomic sector. web 2.0 has been making these following changes in the enterprise management: 1) the pursuit of open innovation from outside 2) active employment of viral marketing through Internet 3) the pursuit of present business transformation 4) strengthening of customer communication through open dialogue. Firms must squarely look at socioeconomic changes owing to web 2.0, and utilize them as business opportunities.

• Journal of Energy Engineering
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• v.2 no.2
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• pp.200-207
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• 1993

A methanol reformer was designed and fabricated using a CuO-ZnO low temperature shift catalyst, and its operation characteristics have been studied for the phosphoric acid fuel cell (PAFC) power generation system. The type of reactor was annular Methanol was consumed both for heating and for reforming fuel. Contents of carbon monoxide produced from the reformer increased as the reaction temperatures increased, but decreased as the mole ratios of water to methanol(H$_2$O/CH$_3$OH) increased. At steady state operating conditional, temperature profile of the catalytic reactor of the reformer was well coincide with the model equation, and it took 50 minutes from start to the rated condition of the reformer. When the system was operated at 4/4 and 1/4 of load, thermal efficiencies of the system were 72.3% and 77%, respectively. When the PAFC system was operated with reformed gas in the range of 62 V-37.6 V and 0-147 A, the trend of I-V curve showed a typical fuel tell characteristic. At steady state condition, the flow rates of reforming and combustion methanol were 88.1 mol/h and 50.1 mol/h, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.7
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• pp.627-635
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• 2015

We propose a dual-layer differential equal-gain codebook design methodology for LTE-Advanced(LTE-A), IEEE802.ac, and radar system having multiple transmit and receive antennas, and make computer simulations to evaluate its link-level performaces. M-ary phase shift keying constellation is used as its codeword elements to utilize low-cost power amplifiers at mobile stations. Especially, the proposed codebook can meet radar systems requirement for the high-powered equal-gain transmission property. Due to the temporal correlation of the adjacent channel, the proposed differential codebook can quantize only the differential information of the channel instead of the whole channel subspace, which virtually increase the codebook size to realize more accurate quantization of the channel. The proposed codebook has the same properties of LTE codebook that is, constant modulus, complexity reduction, and nested property. Computer simulations show that the proposed codebook performs better than the conventional 8-ary codebooks with the same amount of feedback information.

• Journal of Radiation Protection and Research
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• v.36 no.1
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• pp.44-51
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• 2011

Activation foil-based Bonner sphere spheres are used to obtain neutron energy spectra of nuclear power plants or accelerator-produced neutrons. The position and the foil mass dependence of response functions should be studied carefully before measurement of Bonner spheres. This study showed that the normal incidence to the foil surface made a large shift of responses while parallel and isotropic incidence made no position dependence. The correlation between foil mass and response was not linear. Therefore, the response functions of activation-foil based Bonner spheres should be calculated for every different foil mass and the direction of Bonner spheres for parallel incidence will be preferred for radioactive neutron source or accelerator target produced neutrons.

• Transactions of the KSME C: Technology and Education
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• v.1 no.2
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• pp.147-152
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• 2013

In this paper, we surveyed the opinion of MOTIE(Ministry of Trade, Industry and Energy) R&D PDs about what are the future promising industries and their mainly associated Ppuri-technologies. According to the survey result, the future technology trends are to shift the technologies beyond their own critical performance and dominate human-centered technologies through converging technologies. In particular, the 4 industries, personalized medical technology, intelligent and emotional-based system, solar power technology and flexible technology, are expected to be good perspective industries in the near future. In order to grow these industries, we need to develop the core Ppuri-technologies that are very closely related to the future main industries. More than all, Ppuri-technology acts as a leverage for the future promising industry and is expected to be the strong supporter in manufacturing infra.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9C
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• pp.729-734
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• 2010

In the initial stage of the communications between a base station and a satellite transponder, the base station transmits the frequency-sweeping un-modulated up-link carrier within a certain frequency range to acquire the doppler frequency shift and signal power between the base station and the satellite in orbital flight. The satellite transponder acquires and tracks the carrier in order to initialize the communication. To control such initialization process, the satellite receiver should analyze the input carrier signal in various ways. This paper presents an SNR estimation algorithm to control the initialization process. The proposed algorithm converts the input signal into the baseband polar coordinate representation and estimates the SNR via the statistics of the angular signal components as well as the status parameters to control the receiver. The Monte-Carlo simulations shows the validity of the estimation proposed.