• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.35S no.12
• /
• pp.93-102
• /
• 1998

In noisy environments, human speech productions are influenced by noises(Lombard effect), and speech signals are contaminated. These distortions dramatically reduce the performance of speech recognition systems. This paper proposes a method of the Lombard effect compensation and noise suppression in order to improve speech recognition performance in noise environments. To estimate the intensity of the Lombard effect which is a nonlinear distortion depending on the ambient noise levels, speakers, and phonetic units, we formulate the measure of the Lombard effect level based on the acoustic speech signal, and the measure is used to compensate the Lombard effect. The distortions of speech under noisy environments are cancelled out as follows. First, spectral subtraction and band-pass filtering are used to cancel out noise. Second, energy nomalization is proposed to cancel out the variation of vocal intensity by the Lombard effect. Finally, the Lombard effect level controls the transform which converts Lombard speech cepstrum to clean speech cepstrum. The proposed method was validated on 50 korean word recognition. Average recognition rates were 82.6%, 95.7%, 97.6% with the proposed method, while 46.3%, 75.5%, 87.4% without any compensation at SNR 0, 10, 20 dB, respectively.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.3
• /
• pp.3-9
• /
• 2014

Two-way full-duplex relay network provides improved spectral efficiency by using either superposition coding or physical layer network coding at relays compared to conventional two-way half-duplex relay network. In this paper, we investigate the impact of residual loop interference on the performance of the two-way full-duplex relay network. Users and relays in the two-way full-duplex relay network estimate the residual loop interference in order to cancel it. However, it is difficult to perfectly cancel the residual loop interference from the received signal due to the estimation error. Numerical results show the impact of the estimation error on the outage probability of the two-way full-duplex relay network.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.48 no.3
• /
• pp.233-242
• /
• 2020

The history of mankind's lunar exploration began in 1958 with the United States of America "Pioneer 0" mission. In 1950s~1970s, the United States of America and Union of Soviet Socialist Republics carried out missions and experienced numerous failures to explore the moon. Since the 1990s, Japan, Europe, China and other Advanced country in Space technology have started to explore the moon and in 2016, Korea began to develop the lunar orbiter for lunar exploration. This paper analyzed the failure cases and causes of the lunar exploration in the USA and the USSR in the 1950s~1970s according to the mission purpose. Examples of mission delays, cancel, and failures that occurred during lunar exploration in post-1990s were presented. Through the investigation and analysis, this paper is intended to serve as a reference of the lunar exploration mission that Korea is working on or will be performing in the future.

• Journal of Arbitration Studies
• /
• v.15 no.3
• /
• pp.113-137
• /
• 2005

In the provisions of 'the Arbitration Law of China, there are special provisions for international arbitration. When a court refuses the recognition and enforcement of foreign arbitral awards or cancel the domestic awards relating to international arbitration, they have to adopt the provisions of 'Chinese Civil Procedure Law'. These provisions are the same as the provisions of Korean Civil Procedure Law concerning the reasons of renewal. In the Korean Arbitration Act, those provisions disappeared when it was revised on December 31, 1999. Among the characteristics of the Chinese arbitration system, a serious question is that it provides only institutional arbitration and there is no ad-hoc arbitration in the Chinese Arbitration Law. On the other hand, when the parties appoint three arbitrators according to their agreement, the parties appoint the third arbitrator by mutual agreement and when they fail to agree, the Arbitration Committee appoints the third arbitrator. In practice, as the parties hardly agree on the third arbitrator or sole arbitrator, the Committee usually appoints them. And appointing an arbitrator from out of their panel of arbitrators is permitted these days only under examination by the Arbitration Committee in accordance with the arbitration rules of the China International Economic and Trade Arbitration Commission, Other arbitration committees except the China International Economic and Trade Arbitration Commission are still prohibited from making appointments from out of their panel of arbitrators. Accordingly, arbitration in China cannot be predicted and poses a question about legal stability as party autonomy is restricted in the appointment of arbitrators and arbitral procedure. Such being the case it is strongly recommended to select Korea as the place of arbitration in transactions with China. However it is better to arbitrate than to file a law suit in China.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.8B
• /
• pp.797-804
• /
• 2009

Recently, SIP(Session Initiation Protocol) is used to set up and manage sessions for multimedia applications such as VoIP(Voice over IP) and IMS(IP Multimedia Subsystem). However, because SIP operates over the Internet, it is exposed to pre-existed internet security threats such as service degradation or service disruptions. Multimedia applications which are delay sensitive even suffers more from the threats mentioned above. The proposed methods so far to detect SIP INVITE flooding are CUSUM(Cumulative Sum), Hellinger distance and adaptive threshold, but among methods only take normal state into consideration. So, it is not capable of adapting the condition of the network congestion which are dynamically changing. In this paper, SIP INVITE flooding detection algorithm considering network congestion which enables efficient detections of such attacks is proposed. The proposed algorithm is expected to detect other types of attacks such as BYE and CANCEL more precisely compared to other methods.

• Journal of the Ergonomics Society of Korea
• /
• v.31 no.4
• /
• pp.515-523
• /
• 2012

Objective: The aim of this study is to investigate users' intuitive stereotypes on non-touch gestures and establish the gesture dictionary that can be applied to gesture-based interaction designs. Background: Recently, the interaction based on non-touch gestures is emerging as an alternative for natural interactions between human and systems. However, in order for non-touch gestures to become a universe interaction method, the studies on what kinds of gestures are intuitive and effective should be prerequisite. Method: In this study, as applicable domains of non-touch gestures, four devices(i.e. TV, Audio, Computer, Car Navigation) and sixteen basic operations(i.e. power on/off, previous/next page, volume up/down, list up/down, zoom in/out, play, cancel, delete, search, mute, save) were drawn from both focus group interview and survey. Then, a user participatory design was performed. The participants were requested to design three gestures suitable to each operation in the devices, and they evaluated intuitiveness, memorability, convenience, and satisfaction of their derived gestures. Through the participatory design, agreement scores, frequencies and planning times of each distinguished gesture were measured. Results: The derived gestures were not different in terms of four devices. However, diverse but common gestures were derived in terms of kinds of operations. In special, manipulative gestures were suitable for all kinds of operations. On the contrary, semantic or descriptive gestures were proper to one-shot operations like power on/off, play, cancel or search. Conclusion: The touchless gesture dictionary was established by mapping intuitive and valuable gestures onto each operation. Application: The dictionary can be applied to interaction designs based on non-touch gestures. Moreover, it will be used as a basic reference for standardizing non-touch gestures.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.3
• /
• pp.132-139
• /
• 2016

In the bandpass sampling(BPS), the sampling frequency for the analog-to-digital converter is lower than that of the signal to be sampled. Since the BPS operation results in the signal spectrum to be copied on the baseband, it is possible for the frequency down-converter to be conveniently omitted. The second-order BPS system is introduced in order to cancel the aliased interference components from the BPS output that may be generated by the BPS processing. In this paper, we introduce a design method for the optimal phase of the interpolant filter in the second-order BPS system which enables to maximally cancel the aliased components. Being mathematically derived, this method can always be applied independently to the spectral characteristics of the BPS input signal. The performance improvements by the suggested method has been measured statistically with various power spectra of the received signal, and it has been shown that the maximal amount of the improvements reaches up to 5~20 [dB] in comparison with the previous suboptimal algorithm.

• The Korean Journal of Emergency Medical Services
• /
• v.27 no.3
• /
• pp.47-58
• /
• 2023

Purpose: The purpose of this study was to analyze the characteristics of patients who canceled their ED visits and to determine the factors that influence ED cancellation. Methods: Retrospective study that analyzed data from the electronic medical records(EMR) and Prehospital Care Reports(PCRs) of 305 patients who cancelled their appointments at a single emergency medical center over a six-month period from October 12, 2022, to April 12, 2023. Results: ED cancellations were 2.287 times higher if the patient presented to the ambulance after outpatient hours(09:00~17:00) (p=.007), and ED cancellations were 3.712 times higher if the patient presented to the ambulance under the influence of alcohol(p=.011). For patients' symptoms, medical diseases were associated with a 1.965 times increase in cancelled ED visits compared to other modes of transport (p=.005), while mental and chronic diseases were associated with a 67.3% decrease in cancelled ED visits compared to other modes of transport (OR=0.327, CI=[0.130-0.822], p=.018). symptomatic improvement was associated with a 2.482 times increase in presentations to a 119 ambulance compared to delayed waiting time(p=.022). Conclusion: Emergency medical centers should consider improving the legal system, such as increasing emergency medical care fees, to reduce the number of patients who cancel their appointments.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.11 no.2
• /
• pp.125-135
• /
• 2008

Backlash in the actuator is one of the most important nonlinearities that limit the performance of speed and position control of mechanical systems. In this paper, we propose disturbance observers in order to estimate the effect of nonlinearities and cancel them subsequently. As a result the disturbance observers make the nonlinear system behave linearly. And finally we show that the disturbance observers guarantee the system robustness and the performance to reject the effect of backlash in the face of parameter uncertainties.

• Journal of Arbitration Studies
• /
• v.12 no.1
• /
• pp.3-54
• /
• 2002

When the ruling of Foreign Arbitral Awards contradicts the public policy of the enforcement state, it can be a ground for a refusal to enforce the ruling. New York Convention V section 2, UNCITRAL section 36, and Korean arbitration law section 36 confirm this principle. The final ruling of international arbitral awards should be respected according to the international convention or the principle of reciprocity, which cancel out the above principle: when the ruling contradicts the country's public policy, it can be refused to enforcement. Since the Helsinki General Convention, ILA have studied upon it and presented the final report and recommendation during the 2002 New Delhi General Convention. In it, firstly, the finality of awards rendered in the context of international commercial arbitration should be respected save in exceptional circumstances. Secondly, every state is recommended the “international public policy”, on which it can refuse to follow the ruling of international arbitral awards, and advised to respect it as far as possible.