Earticle

본 연구는 공급네트워크에서 기업의 성장과 수익성을 좌우하는 요인을 탐색하는 것을 주된 목적으로 한다. 기존 연구들은 자료의 부족으로 전체 공급네트워크 분석이 아닌 사례연구나 에고 네트워크 분석에 그쳤다는 한계가 있었다. 본 연구는 공급네트워크에서 각 기업들이 차지하는 위치가 원청기업과 하청기업 간의 경쟁력과 생존가능성 격차에 어떤 영향을 미치는지, 그리고 공급기업들은 어떤 전략으로 장기적인 생존과 성장을 꾀할 수 있는지를 네트워크 관점에서 살펴보았다. 삼성전자를 대상으로 한 전자산업 거래 기업 952개의 매입 및 매출 거래 데이터를 4년 간격의 두 시점에서 수집하여 분석하였다. 삼성전자의 공급네트워크 관리 특성에 대한 정성적 분석, 네트워크 이탈 기업과 1차 공급기업 지위 유지 기업 간 비교분석, 그리고 2·3차 공급기업까지 포함한 에고 네트워크 분석을 통해 네트워크 위치 변동의 특성을 규명하였다. 탐색적 사례 분석 결과, 첫째, 공급기업과 수요기업 간 거래 관계가 장기화될수록 성과 연동성이 높아져 장기 거래 관계를 유지하는 기업이 수요기업의 성과 변화에 더욱 민감하게 반응하는 것으로 나타났다. 둘째, 삼성전자와 장기간에 걸쳐 강한 배태성을 유지하는 기업들은 높은 품질과 신뢰를 기반으로 안정적인 매출과 혁신 성과를 확보하였으며, 환경 변화 시 수요기업의 위험까지 공유하는 경향을 보였다. 셋째, 삼성전자는 일본 토요타식 폐쇄적 네트워크 전략과 미국 시장 기반의 개방적 네트워크 전략을 통합적으로 활용하고 있으며, 2·3차 공급기업을 직거래로 전환할 시 일정한 유예기간을 두어 기존 협력사와의 신뢰 관계 훼손을 방지하고 있다. 본 연구는 공급네트워크 내 공급기업들을 수동적 존재가 아닌, 구조와 내부 역량을 전략적으로 활용하여 적극적으로 네트워크 구조를 변화시키는 능동적 행위자로 재개념화함으로써 조직 전략 이론에 기여한다. 나아가, 공급네트워크 구조 조정을 위한 전략적 행동과 원청-하 청 간 관계에서 기업 경쟁력 증진을 위한 정책적 시사점을 제공한다.

This study seeks to explore the key factors that determine corporate growth and profitability within supply networks. Previous research has been limited to case studies or ego network analyses due to data constraints, lacking comprehensive supply network analysis. This study examines how firms' positions in supply networks affect the competitiveness and survival prospects gaps between buyers and suppliers, and explores what strategies suppliers can employ to achieve long-term survival and growth from a network perspective. Samsung Electronics, a representative firm in Korea's electronics industry, was selected as the research subject. Transaction data from 952 firms in the electronics industry were collected at two time points four years apart, focusing on Samsung Electronics. The study conducted qualitative analysis of Samsung Electronics' supply network management characteristics, comparative analysis between firms that exited the network and those that maintained their first-tier supplier status, and ego network analysis including second and third-tier suppliers to identify the characteristics of network position dynamics. The exploratory case analysis yields three key findings. First, the longer the trading relationship between suppliers and buyers, the higher the performance synchronization, with firms maintaining long-term relationships responding more sensitively to buyers' performance changes. Second, firms maintaining strong embeddedness with Samsung Electronics over extended periods secured stable sales and innovation outcomes based on high quality and trust, and notably tended to share buyer risks during environmental changes. Third, Samsung Electronics integrates both Japanese Toyota-style closed network strategies and American market-based open network approaches, and when transitioning second and third-tier suppliers to direct transactions, implements grace periods to prevent damage to existing trust relationships. This research contributes to organizational strategy theory by reconceptualizing suppliers within supply networks not as passive entities but as active agents who strategically utilize network structure and internal capabilities to actively transform their network positions. Furthermore, this study provides policy implications for strategic actions in supply network restructuring and for enhancing corporate competitiveness in buyer-supplier relationships.

The objectives of experiments were to compare directly the effects of synchrony of slowly fermented(corn and corn gluten meal; C-CGM) and of rapidly fermented ingredients(barley and soybean meal; B-SBM) in the rumen on starch disappearances in gastrointestinal tracts(Experiment 1) and growth performance(Experiment 2) of Hanwoo steers in the feedlot barn. In experiment 1, four Hanwoo steers(288±21kg) fitted with ruminal and “T” shaped duodenal cannula were placed in one pen with Calan gate and assigned randomly to a duplicate 2×2 Latin square design. In experiment 2, eight intact Hanwoo steers(311 ±8kg) were assigned randomly to one of two pens with Calan gate to evaluate the effect of the same diets as like in experiment 1 on growth performance. There were no differences in ruminal pH, ammonia and total VFA concentrations between treatments. Percentage of apparent ruminal starch disappearance was 33.3% unit lower(p<0.05) for steers fed C-CGM than for steers fed B-SBM diets and this difference resulted in 268% higher(p<0.05) in duodenal starch flows for steers fed C-CGM diet than for steers fed B-SMB diet. There was significant increase(p<0.05) in quantity(927 vs. 400 g/d) of corn starch digested post-ruminally compared to barley starch. However, percentage of starch apparently digested post-ruminally was 8% higher(p=0.1) in steers fed fast synchrony diet with B-SBM than in steers fed slow synchrony diets with C-CGM. The differences of percentage and amount of starch apparently digested post-ruminally between C-CGM and B-SBM diets did not affect rice straw DM intake, average daily gain(ADG) and feed efficiency. In conclusion, there is some uncertainty in regards to the relationship between site of starch digestion and DM intake, ADG, and feed efficiency in this study.

This paper analyzes underwater OFDM system's timing synchronization performance by simulating the channel impulse response of three Korean Peninsula coastal sea based on HFM and Zadoff-chu sequences (ZCS). Simulation results show that the timing synchronization performance varies depending on the characteristics of the three seas, and the ZCSbased fine synchronization algorithm improves the synchronization performance in all three sea areas compared to coarse synchronization.

본 논문에서는 의사위성과 GPS 위성 사이의 시각동기를 위한 세가지 동기 방안을 제안하고 시각동기 기법의 성능 분석에 필요한 의사위성 시각동기 오차요소에 대해 분석한다. 제시한 세가지 시각동기 방안으로는 의사위성 시각동기 스테이션 구축 방안, UTC(KRIS)의 시각정보원을 활용한 의사위성 시각동기 방안, GPS 시각용 수신기를 활용한 시각동기 방안이 있다. 또한 제안한 의사위성 시각동기 방안의 성능평가를 위한 시뮬레이션 구성을 위해 의사위성 시각동기 방안의 오차요소를 의사위성 및 기준 클럭의 오차, 전송선로에 의해 발생하는 오차, TIC에 의해 발생하는 오차, 클럭 동기 알고리즘에 의해 발생하는 오차로 구분하고 각 오차 요소를 분석하였다.

This paper proposes three methods of the time synchronization for Pseudolite and GPS and analyzes pseudolite time synchronization error factors for software based performance evaluation on proposed time synchronization methods. Proposed three time synchronization methods are pseudolite time synchronization station construction method, method by using UTC(KRIS) clock source and GPS timing receiver based time synchronization method. Also, we analyze pseudolite time synchronization error factors such as errors of pseudolite clock and reference clock, time delay as clock transmission line, measurement error of time interval counter and error as clock synchronization algorithm to design simulation platform for performance evaluation of pseudolite time synchronization.

다중 빔을 사용하는 위성통신시스템의 효율을 비약적으로 증대시키기 위하여 사용하는 빔 호핑 기술의 경우, 트래픽 요구량에 따라 적응적으로 통신을 위한 자원이 할당되어야 하므로 비연속적 불규칙 길이를 갖는 데 이터 전송이 이루어져야 한다. 따라서, 비주기적 운용을 위한 시분할 싸이클로 인하여 빔 호핑 프레임 동기가 중 요하다. 본 논문은 DVB-S2X 표준의 빔 호핑 수퍼프레임에 기반한 빔 호핑 프레임 동기 기법에 대해 비교하고, 이에 기반한 수퍼프레임 종류에 상관없이 블라인드 프레임 동기가 가능한 고성능 동기 기법을 제안한다. 제안된 다중 빔을 사용하는 빔 호핑 위성통신시스템을 위한 프레임 동기 기법의 우수성을 실제 빔 호핑 시나리오에 대하 여 모의실험을 실시하여 제안된 프레임 동기 기법의 성능을 기존 방법들과 비교 분석하였다.

In the case of beam hopping technology used to increase the efficiency of multi-beam based satellite communication systems dramatically, data transmission with discontinuous irregular burst lengths must be made because resources for communication must be assigned adaptively according to traffic requirements. Therefore, frame synchronization for beam hopping system is important due to the aperiodic time cycle for beam illumination. In this paper, frame synchronization schemes based on the DVB-S2X standard's beam hopping superframe were compared, and a high-performance synchronization method that enables blind frame synchronization regardless of the type of superframe was proposed. The performance of the proposed frame synchronization method was compared and analyzed with existing ones through simulations.

This paper proposes a method to improve the position control synchronization performance by synchronizing the controller operation between servo drives based on the synchronization signal of the EtherCAT(Ethernet for Control Automation Technology)distributed clock. In order to synchronize the operation of the controller between the servo drives, the phase of the operating frequency of the PWM(Pulse Width Modulation) module for motor control was synchronized based on the synchronization signal. At this time, the operation sequence of the current, speed, and position controller of the servo drive operating based on the PWM operating frequency was rearranged. Therefore, the servo drives on the network run the same controller at the same time. And the time at which the master's command is reflected to the drive's controller and the time at which the drive's status information is acquired coincided among the drives. After establishing an experimental environment in which servo drives are arranged in the EthercCAT network system, we verified that the position synchronization performance between servo drives applying the proposed method is improved.

In this paper, we propose a simple OFDM (orthogonal frequency division multiplexing) frame synchronization scheme for high-speed LED communication systems. Frame synchronization is an essential procedure for normal operation of the OFDM systems on account of sensitivity to synchronization errors. In order to enhance the OFDM frame synchronization performance, we add a repeated orthogonal Gold sequence (ROGS) directly to OFDM signals in the time domain. The power level of a ROGS needs to be low enough in order not to affect a normal operation of the LED communication systems. Frame synchronization can be achieved successfully over optical channels interfered by impulsive noise owing to good auto-correlation properties of the ROGS.

본 논문에서는 이동통신, 무인기 통신, 차량 간 통신 등에 이용될 수 있는 효율적인 단말 간 직접통신 (D2D: device-to-device)을 위한 동기 프리앰블 (preamble) 구조를 제안하고 성능을 비교한다. 단말 간 직접 통신을 위해서는 향상된 주파수 및 시간 동기 요구 성능을 만족 시킬 수 있어야 하며, 본 논문에서는 이를 위한 프리앰블 구조를 제안한다. 주파수 영역에서 하나 걸러 하나씩의 부 반송파에는 신호를 전송하지 않는 대신, 나머지 부반송파에서는 심볼 당 에너지를 2배로 전송하는 제안하는 구조가 기존 LTE D2D 프리앰블 구조에 비해 주파수 옵셋 추정 성능은 유지하면서도 시간 옵셋 추정 성능을 크게 향상시킴을 확인하였다.

In this paper, an efficient structure of device-to-device (D2D) synchronization preamble is proposed to meet the enhanced time and frequency synchronization requirements for D2D communication. D2D communication can be applied not only for the cellular communications, but also unmaned aerial vehicle communications and vehicle-to vehicle communication. The proposed preamble structure is transmitting signals at every odd subcarriers, and empty the other subcarriers to minimize the effect of inter-carrier interference. According to the simulation results, the proposed preamble structure provides improved time offset estimation performance, without degrading frequency offset estimation performance compared to the current LTE D2D preamble.

This paper considers the problem of sampling frequency offset (SFO) estimation for orthogonal frequency division multiplexing (OFDM) based digital radio mondiale (DRM) systems. In this study, the mean square error (MSE) expression for conventional SFO estimators is derived and their low-complexity variants are reported. The theoretical MSE analysis for different algorithms are validated by Monte-Carlo simulations and proven accurate.

Many synchronization algorithms for orthogonal frequency division multiplexing (OFDM) systems have been proposed. Among them, the time synchronization algorithm by correlating the training sequence with the local known sequence can obtain good performance with a sharp synchronization peak. Detection threshold is an important and necessary parameter in time synchronization. In this paper, based on this algorithm, we evaluate three different methods of setting threshold and point out one method which performs well when SNR is in large dynamic range. The simulation results are consonant with our theoretic analyses and show that this method is suitable for OFDM systems in multi-path fading channel.

전술데이터링크는 전장 환경에서 모든 플랫폼들을 네트워크를 통해 하나로 묶어 전쟁 효과를 극대화할 수 있는 기반이 되는 통신 기술이다. 이러한 전술데이터링크의 원활한 운영을 위해 플랫폼간 시간 동기가 필수적이며, 대부분 GPS(Global Positioning System)를 사용하고 있다. 전세계적으로 가장 널리 사용되고 있는 전술데이터링크인 Link-16 에서는 네트워크에 가입하면서 NTR(Network Time Reference) 과의 시간을 동기화하는 절차를 제공한다. 이러한 시간 동기 절차는 대략적인 동기와 정밀한 동기의 두 단계로 구분된다. 대략적인 동기는 프레임이 시작하는 첫 타임 슬롯에서 주변 노드로부터 IEM(Initial Entry Message)을 수신하여 전송 시간만큼의 오류를 포함하는 시간 동기 방식이다. 본 논문에서는 모의 실험을 통해 IEM 을 전송하는 노드의 거리에 따른 메시지의 충돌 확률을 구하고, 그 충돌 확률에 따라 시간 동기에 소요되는 시간으로 Link-16 의 시간 동기 성능을 분석하였다.

A pseudolite is used as a GPS backup system, and is also used for the purpose of indoor navigation and correction information transmission. It is installed on the ground, and transmits signals that are similar to those of a GPS satellite. In addition, in recent years, studies on the improvement of positioning accuracy using the pseudorange measurement of a pseudolite have been performed. As for the effect of the time synchronization error between a pseudolite and a GPS satellite, a time synchronization error of 1 us generally induces a pseudorange error of 300 m; and to achieve meter-level positioning, ns-level time synchronization between a pseudolite and a GPS satellite is required. Therefore, for the operation of a pseudolite, a time synchronization algorithm between a GPS satellite and a pseudolite is essential. In this study, for the time synchronization of a pseudolite, "a pseudolite time synchronization method using the time source of UTC (KRIS)" and "a time synchronization method using a GPS timing receiver" were introduced; and the time synchronization performance depending on the pseudolite time source and reference time source was evaluated by designing a software-based pseudolite time synchronization performance evaluation simulation platform.

This paper analyzed how the country’s institutional and political environment affect ESG performance of the companies in the country. An empirical analysis of this study results are as follows. First, the clear difference in financial variables such as the growth rate of foreign direct investment, pension fund assets to GDP ratio, and stock market return rate was found to the significance between advanced economies and emerging markets. Second, in two groups, the institutional indexes, which refer to government policy and the country’s institutional environment such as the rule of law, the government effectiveness, corruption control, and citizens’ voice and accountability showed a positive relationship with ESG performance of the companies. They had a particularly large positive effect on the companies in emerging markets. And third, companies’ synchronization with other companies’ high ESG performance had a positive effect on their ESG performance, and such a tendency was much stronger in the companies of emerging markets. Additionally, institutional dimension had a positive effect on the companies’ synchronization, and such a tendency was much stronger in emerging markets.

The objectives of experiments were to compare directly the effects of synchrony of slowly fermented (corn and corn gluten meal; C-CGM) and of rapidly fermented ingredients (barley and soybean meal; B-SBM) in the rumen on starch disappearances in gastrointestinal tracts (Experiment 1) and growth performance (Experiment 2) of Hanwoo steers in the feedlot barn. In experiment 1, four Hanwoo steers ($288{\pm}21$ kg) fitted with ruminal and "T" shaped duodenal cannula were placed in one pen with Calan gate and assigned randomly to a duplicate $2{\times}2$ Latin square design. In experiment 2, eight intact Hanwoo steers ($311{\pm}8$ kg) were assigned randomly to one of two pens with Calan gate to evaluate the effect of the same diets as like in experiment 1 on growth performance. There were no differences in ruminal pH, ammonia and total VFA concentrations between treatments. Percentage of apparent ruminal starch disappearance was 33.3% unit lower (p<0.05) for steers fed C-CGM than for steers fed B-SBM diets and this difference resulted in 268% higher (p<0.05) in duodenal starch flows for steers fed C-CGM diet than for steers fed B-SMB diet. There was significant increase (p<0.05) in quantity (927 vs. 400 g/d) of corn starch digested post-ruminally compared to barley starch. However, percentage of starch apparently digested post-ruminally was 8% higher (p=0.1) in steers fed fast synchrony diet with B-SBM than in steers fed slow synchrony diets with C-CGM. The differences of percentage and amount of starch apparently digested post-ruminally between C-CGM and B-SBM diets did not affect rice straw DM intake, average daily gain (ADG) and feed efficiency. In conclusion, there is some uncertainty in regards to the relationship between site of starch digestion and DM intake, ADG, and feed efficiency in this study.

We have developed 140Mb/s and 565Mb/s muldexes as parts of a 565Mb/s Optical Fiber Transmission System. Bunched frame structures are used for these muldexes. In this paper we describe their frame synchronization performance.

연구목적: 본 연구의 목적은 짝 드럼 연주에서 측정된 대인간 동기화 과제 수행력을 통해 자폐스펙트럼장애(ASD) 아동의 사회운동기술을 평가하는 데 있다. 연구방법: 평균 연령 9.9세의 ASD 아동 11명은 연구자와 짝을 이루어 연구자의 탭핑에 맞추어 드럼을 탭핑하는 과제에 참여하였고, 동기화 지시, 음악적 큐, 탭핑 속도 등 다양한 조건에서 그 수행력이 평가되었다. 대인간 동기화 수행력은 정확도(동기화 오류값), 일관성(동기화 오류의 변동계수), 즉각성(동기화 시점)의 측면에서 분석되었다. 연구결과: 분석 결과, 동기화 지시나 음악적 큐가 제공될 때 동기화 정확도와 즉각성이 유의하게 높아지는 것으로 나타났다. 또한 각 대인간 동기화 지표는 전반적인 자폐의 특질, 보다 구체적인 사회기술, 운동 조절을 측정하는 지표와의 상관관계에 있어 서로 다른 양상을 보였다. 결론: 본 연구 결과는 ASD 아동의 사회운동기술을 평가하는 다양한 접근법을 제시하며, 개별적인 필요에 따라 과제를 조정하는 전략을 제안한다.

Purpose: This study aimed to assess the social motor skills of children with autism spectrum disorder (ASD) through interpersonal synchronization during dyadic drumming. Method: Eleven children with ASD, with a mean age of 9.9 years, engaged in drum tapping in sync with an investigator, adapting to varying conditions involving synchronization directions, musical cueing, and tempo changes. Their performance was evaluated for accuracy (synchronization errors), precision (coefficient of variation), and immediacy (synchronization timing). Results: Explicit directions and musical cueing significantly improved accuracy and immediacy in synchronization. Tempo adjustments also had significant effects on performance. Furthermore, each measure, representing distinct aspects of synchronization, correlated differently with overall autistic traits, specific social skills, and motor control. Conclusion: This study suggests alternative approaches to understand social motor skills, proposing task adjustments tailored to this population.

해양 4차 산업의 신기술 도입과 해상 물류 증가로 통항로가 복잡해지고 배후광의 증가로 항로표지의 시인성 개선이 요구되고 있다. 국제항로표지기구에서는 동기/순차점멸을 활용하여 광파표지의 시인성 개선을 제안하고 있으며, 국내·외 일부 항로에서는 측방표지에 동기 및 순차점멸를 적용하여 항로표지의 인식률을 높이고 있다. 국내 항로표지 장비용품 등 기능 및 규격 기준에서는 GPS 수신기의 시각 및 1PPS를 활용하여 등명기의 점멸 동기를 맞추도록 고시하고 있지만, 업체마다 사용하는 GPS 모듈 및 구현 방법이 달라 검사를 통하여 일원화된 성능을 구현할 필요가 있다. 본 논문에서는 일원화된 성능을 구현할 수 있는 검사 방법을 제안한다.

With the introduction of new technologies and the growth of maritime logistics, there is an increasing demand for improved visibility of aids to navigation due to the complexity of fairways and the rise in backlighting. The International Organization for Marine Aids to Navigation recommends enhancing lantern visibility by employing synchronous or sequential flashing. Some fairways are already implementing this technique on lateral marks to improve the visibility of aids to navigation. In Korea, it has been noted that the GPS receiver's time and 1PPS signal should be used to synchronize the flashing of lanterns. However, since lanterns from different manufacturers exhibit varying performances, it is essential to establish a unified standard through inspection. This paper proposes a method for inspecting the performance of lanterns to ensure consistency.